ANODE PIECE FOR LITHIUM BATTERY HAVING BOTH HIGH SAFETY AND HIGH CAPACITY, AND PREPARATION METHOD AND USE THEREFOR
20230216023 · 2023-07-06
Assignee
Inventors
- Wenjun LI (Beijing, CN)
- Qiufeng DING (Beijing, CN)
- Hao YANG (Beijing, CN)
- Hangyu XU (Beijing, CN)
- Haiyun MA (Beijing, CN)
- Zepeng DING (Beijing, CN)
- Yadan WANG (Beijing, CN)
- Yongwei LI (Beijing, CN)
- Huigen YU (Beijing, CN)
Cpc classification
H01M4/62
ELECTRICITY
H01M4/485
ELECTRICITY
H01M4/525
ELECTRICITY
H01M50/451
ELECTRICITY
H01M4/505
ELECTRICITY
H01M4/131
ELECTRICITY
Y02E60/10
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01M2004/021
ELECTRICITY
H01M10/0525
ELECTRICITY
International classification
H01M4/36
ELECTRICITY
H01M4/505
ELECTRICITY
H01M4/131
ELECTRICITY
Abstract
An anode piece for a lithium battery having both high safety and high capacity, and a preparation method and a use therefor, the anode piece being mixed with a lithium-rich compound, the lithium-rich compound being at least one selected from lithium-rich manganese-based solid solution, a lithium-rich solid electrolyte or a lithium-separated silicon oxide. Li ions can be pulled away from the lithium-rich compound in extreme conditions such as overcharging, internal short circuiting, external short circuiting, thermal abuse, piercing, compressing or overheating, thereby filling in lithium vacancies in the anode material, stabilizing the crystal lattice structure of the anode material, improving safety performance in a battery manufactured by using the material, and allowing the anode piece to maintain excellent cycle performance at higher area capacities.
Claims
1. An positive piece for a lithium battery, wherein the positive piece for a lithium battery is doped and mixed with a lithium-rich compound, and the lithium-rich compound is at least one selected from the group consisting of a lithium-rich manganese-based solid solution, a lithium-rich solid electrolyte and a lithium-separated silicon oxide.
2. The positive piece for a lithium battery of claim 1, wherein the lithium-rich compound is capable of pulling away Lithium-ions under extreme conditions of battery; preferably, the extreme conditions of battery include at least one of overcharging, high temperature, piercing, compressing, internal short circuiting, external short circuiting, thermal abuse or overheating; preferably, the lithium-rich manganese-based solid solution is represented by the molecular formula xLi.sub.2MnO.sub.3•(1-x) LiMO.sub.2, wherein 0 < x ≤ 1, and M is at least one selected from Ni, Co or Mn.
3. The positive piece for a lithium battery of claim 1 or 2, wherein the lithium-rich solid electrolyte is selected from Li.sub.7La.sub.3Zr.sub.2O.sub.12 and materials obtained after subjecting Li.sub.7La.sub.3Zr.sub.2O.sub.12 to doping with other element, wherein the doping element is at least one selected from the group consisting of La, Nb, Sb, Ga, Te, W, Al, Sn, Ca, Ti, Hf and Ta.
4. The positive piece for a lithium battery of any one of claims 1-3, wherein the lithium-separated silicon oxide is represented by the molecular formula Li.sub.xSiO.sub.y, wherein x is selected from a range of 1.4-2.1, and y is selected from a range of 0.9-1.1.
5. The positive piece for a lithium battery of any one of claims 1-4, wherein the lithium-rich compound has a particle diameter D50 within a range of 0.1-10 .Math.m, preferably a range of 0.5-2 pm.
6. The positive piece for a lithium battery of any one of claims 1-5, wherein the percentage content by mass of the lithium-rich compound is 0.1-20%, preferably 1-5%, based on the sum 100% of the mass of the anode active material and the lithium-rich compound in the positive piece for a lithium battery.
7. The positive piece for a lithium battery of any one of claims 1-6, wherein the positive piece for a lithium battery has an area capacity larger than or equal to 4 mAh/cm.sup.2; preferably, the anode active material in the positive piece for a lithium battery is represented by the molecular formula LiNi.sub.xCo.sub.i-x-yM.sub.yO.sub.2, where x ≥ 0.8, y < 0.2, and M is any one of Mn, Al or Mg, or a combination of at least two thereof.
8. A method of preparing the positive piece for a lithium battery of any one of claims 1 to 7 compring: pre-mixing anode active material with lithium-rich compound to obtain a premixed powder; and blending the premixed powder, glue solution and conductive agent to obtain an anode sizing agent; and coating the anode sizing agent on a current collector to obtain a coated current collector, subjecting the coated current collector to drying, cold pressing and tableting process, so as to prepare the positive piece for a lithium battery; preferably, the pre-mixed powder, the glue solution and the conductive agent are blended in such a manner that the glue solution is added to the premixed powder, the conductive agent is then added to obtain the anode sizing agent.
9. A battery comprising the positive piece for a lithium battery of any one of claims 1-7; preferably, the battery further comprises a negative piece, a cathode active material in the negative piece is selected from silicon oxide and/or silicon carbon; preferably, the negative piece comprises a cathode active material, a conductive agent, a thickening agent and a binder; preferably, the battery further comprises a diaphram.
10. The battery of claim 9, wherein the diaphram is selected from diaphrams coated with a ceramic interlayer; preferably, the diaphrams have a thickness of 10-40 .Math.m and a porosity of 20-60%.
11. A ternary positive piece for a lithium battery having both high safety and high capacity comprising a current collector and an anode active material layer disposed on a surface of the current collector, wherein the anode active material layer comprises an oxide solid electrolyte capable of transporting Lithium-ions, the oxide solid electrolyte is composed of porous spherical particles.
12. The ternary positive piece of claim 11, wherein the porous spherical particles have a porosity within a range of 5-70%, preferably 40-70%.
13. The ternary positive piece of claim 11 or 12, wherein the oxide solid electrolyte has a particle diameter within a range of 0.1-10 .Math.m, preferably 0.5-3pm.
14. The ternary positive piece of any one of claims 11-13, wherein the percentage content by mass of the oxide solid electrolyte is 0.1-10%, preferably 1-5%, based on the sum 100% of the mass of the anode active material and the oxide solid electrolyte in the anode active material layer.
15. The ternary positive piece of any of claims 11-14, wherein the oxide solid electrolyte comprises at least one selected from the group consisting of a NASICON structure, a perovskite structure, an inverse perovskite structure, a LISICON structure and a garnet structure; preferably, the NASICON structure is at least one selected from the group consisting of Li.sub.1+.sub.xAl.sub.xGe.sub.2-x(PO.sub.4).sub.3, isomorphic heteroatom-doped compounds of Li.sub.i+xAl.sub.xGe.sub.2-x(PO.sub.4).sub.3, Li.sub.1+yAl.sub.yTi.sub.2-y(PO.sub.4).sub.3 and isomorphic heteroatom-doped compounds of Li.sub.i1+.sub.yAl.sub.yTi.sub.2-y(PO.sub.4).sub.3; preferably, the perovskite structure is at least one selected from the group consisting of Li.sub.3zLa.sub.⅔-zTiO.sub.3, isomorphic heteroatom-doped compounds of Li.sub.3zLa.sub.⅔-.sub.zTiO.sub.3, Li.sub.⅜Sr.sub.7/16Ta.sub.¾Hf.sub.¼O.sub.3, isomorphic heteroatom-doped compounds of Li.sub.⅜Sr.sub.7/16Ta.sub.¾Hf.sub.¼O.sub.3, Li.sub.2a-bSr.sub.1-aTa.sub.bZn.sub.1-bO.sub.3 and isomorphic heteroatom-doped compounds of Li.sub.2a-bSr.sub.1-aTa.sub.bZr.sub.1-bO.sub.3; preferably, the inverse perovskite structure is at least one selected from the group consisting of Li.sub.3-.sub.2xM.sub.xHa1O, isomorphic heteroatom-doped compounds of Li.sub.3-.sub.2xM.sub.XHa1O, Li.sub.3OC1 and isomorphic heteroatom-doped compounds of Li.sub.3OC1; wherein Hal comprises Cl and/or I, and M is any one of Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, or Ba.sup.2+, or a combination of at least two thereof; preferably, the LISICON structure is at least one selected from the group consisting of Li.sub.4-cSi.sub.1-cP.sub.cO.sub.4, isomorphic heteroatom-doped compounds of Li.sub.4-cSi.sub.1-cP.sub.cO.sub.4, Li.sub.14ZnGe.sub.4O.sub.16, and isomorphic heteroatom-doped compounds of L1.sub.14ZnGe.sub.4O.sub.16; preferably, the garnet structure is selected from Li.sub.7-dLa.sub.3Zr.sub.2-dO.sub.12 and/or isomorphic heteroatom-doped compounds of Li.sub.7-dLa.sub.3Zr.sub.2-dO.sub.12.
16. The ternary positive piece of any one of claims 11-15, wherein the ternary positive piece has an area capacity larger than or equal to 4mAh/cm.sup.2.
17. The ternary positive piece of any one of claims 11-16, wherein the anode active material in the anode active material layer is selected from a high nickel ternary material; preferably, the high nickel ternary material comprises lithium nickel cobalt manganate and/or lithium nickel cobalt aluminate. Preferably, the lithium nickel cobalt manganate is represented by the molecular formula LiNi.sub.xCoMn.sub.1-x.sub.–yO.sub.2 and the lithium nickel cobalt aluminate is represented by the molecular formula LiNi.sub.xCoA1.sub.1.sub.-x.sub.–yO.sub.2, wherein x ≥ 0.6.
18. A method of preparing the ternary positive piece of any one of claims 11-17 comprising: Pre-mixing an anode active material with an oxide solid electrolyte to obtain a pre-mixed powder; and adding a glue solution and a conductive agent into the pre-mixed powder to obtain a mixture, and blending the mixture to form an anode sizing agent; and coating the anode sizing agent on a current collector to obtain a coated current collector, subjecting the coated current collector to drying so as to prepare the ternary positive piece.
19. A lithium battery comprising the ternary positive piece of any one of claims 11-17.
20. The lithium battery of claim 19, wherein the lithium battery comprises any one of a liquid lithium battery, a semi-solid lithium battery and an all-solid lithium battery; preferably, the liquid lithium battery comprises the ternary positive piece of any one of claims 11-17, a negative piece and a liquid electrolyte; preferably, the semi-solid lithium battery comprises the ternary positive piece of any one of claims 11-17, a negative piece, and an electrolyte layer containing a liquid electrolyte material; preferably, the solid-state lithium battery comprises the ternary positive piece of any one of claims 11-17, a negative piece and a solid electrolyte layer; preferably, the solid electrolyte in the solid electrolyte layer is at least one selected from the group consisting of a polymer solid electrolyte, an oxide solid electrolyte and a sulfide solid electrolyte.
21. A ternary positive piece for a lithium battery comprising a current collector and an anode material layer disposed on a surface of the current collector, the anode material layer comprising ternary anode active material particles, a conductive agent, a binder, and oxide solid electrolyte particles capable of conducting Lithium-ions; the positive piece has an area capacity larger than or equal to 4 mAh/cm.sup.2; the oxide solid electrolyte particles has a particle diameter D50 within a range of 0.1-3 .Math.m.
22. The positive piece of claim 21, wherein the oxide solid electrolyte particles have a particle diameter D50 within a range of 0.5-2 .Math.m; preferably, the content of the ternary anode active material particles is 80-98%, based on a total mass 100% of the ternary anode active material particles, the conductive agent, the binder and the oxide solid electrolyte particles; preferably, the content of the oxide solid electrolyte is 0.1-10%, preferably 1-5%, based on the total mass 100% of the ternary anode active material particles, the conductive agent, the binder and the oxide solid electrolyte particles; preferably, the content of the conductive agent is 0.1-8%, based on the total mass 100% of the ternary anode active material particles, the conductive agent, the binder and the oxide solid electrolyte particles; preferably, the content of the binder is 0.1-10%, based on the total mass 100% of the ternary anode active material particles, the conductive agent, the binder and the oxide solid electrolyte particles.
23. The positive piece of claim 21 or 22, wherein the oxide solid electrolyte particles comprise any one of the following compounds or a combination of at least two thereof: Li.sub.1+x1Al.sub.x1Ge.sub.2-x1(PO.sub.4).sub.3 of the NASICON structure or isomorphic heteroatom-doped compounds thereof; Li.sub.1+.sub.X2Al.sub.x2Ti.sub.2-x2(PO.sub.4).sub.3 of the NASICON structure or isomorphic heteroatom-doped compounds thereof; Li.sub.3x3La.sub.⅔-x3TiO.sub.3 of the perovskite structure or isomorphic heteroatom-doped compounds thereof; Li.sub.⅜Sr.sub.71i6Ta.sub.¾Hf.sub.¼O.sub.3 of the perovskite structure or isomorphic heteroatom-doped compounds thereof; Li.sub.2x4-y1Sr.sub.1-x4Ta.sub.y1Zr.sub.1-y1O.sub.3 of the perovskite structure or isomorphic heteroatom-doped compounds thereof; Li.sub.3-2x5M.sub.x5Ha1O and Li.sub.3OC1 of an inverse perovskite structure or isomorphic heteroatom-doped compounds thereof; Li.sub.4-x6Si.sub.1-.sub.x.sub.6P.sub.x6O.sub.4 of the LISICON structure or isomorphic heteroatom-doped compounds thereof; Li.sub.14ZnGe.sub.4O.sub.16 of the LISICON structure or isomorphic heteroatom-doped compounds thereof; Li.sub.7-x7La.sub.3Zr.sub.2.sub.–x.sub.7O.sub.12 of the garnet structure or isomorphic heteroatom-doped compounds thereof; wherein 0<xl≤0.75, 0<x2≤0.5, 0.06≤x3≤0.14, 0.25≤y1≤1, x4=0.75y1, 0≤x5≤0.01, 0.5≤x6≤0.6; 0≤x7≤1; wherein M includes any one of Mg.sup.2+, Ca.sup.2+, Sr.sup.2+ or Ba.sup.2+ or a combination of at least two thereof, and Hal is element Cl or I; preferably, the oxide solid electrolyte particles comprise Li.sub.1+x2Al.sub.x2Ti.sub.2-x2(PO.sub.4).sub.3 and/or Li.sub.7.sub.–x.sub.7La.sub.3Zr.sub.2-x7O.sub.12,preferably Li.sub.1+x2Al.sub.x2Ti.sub.2-x2(PO.sub.4).sub.3.
24. The positive piece of any one of claims 21-23, wherein the ternary anode active material particles comprise lithium nickel cobalt manganate and/or lithium nickel cobalt aluminate; preferably, the ternary anode active material particles are represented by the molecular formula LiNi.sub.xCo.sub.yM.sub.1-x-yO.sub.2, M is Mn and/or Al, and x ≥ 0.6. Preferably, the conductive agent includes any one of Super-P, KS-6, carbon black, carbon nanofiber, CNT, acetylene black or grapheme, or a combination of at least two thereof, preferably a combination of carbon nanotube and Super-P; preferably, the binder comprises any one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene oxide, polytetrafluoroethylene, or a combination of at least two thereof.
25. The positive piece of any one of claims 21-24, wherein a ratio of the particle diameter D50 of the ternary anode active material particles to the particle diameter D50 of the oxide solid electrolyte particles is larger than or equal to 5.
26. A method of preparing the positive piece of any one of claims 21-25 comprising: S1: pre-mixing anode active material particles and oxide solid electrolyte particles to obtain a pre-mixed material, wherein the anode active material particles comprising ternary anode active material particles; S2: adding a glue solution as a binder to the premixed material to obtain a primary sizing agent; S3: adding a conductive agent to the primary sizing agent to obtain a mixture, and blending the mixture to obtain a secondary sizing agent; S4: coating the secondary sizing agent on a current collector to obtain a coated current collector, controlling an area capacity of the positive piece to be larger than or equal to 4mAh/cm.sup.2, subjecting the coated current collector to baking and rolling, so as to prepare the positive piece.
27. The method of claim 26, wherein the pre-mixing is a vacuum pre-mixing or a pre-mixing performed at a dew point ≤ -30° C.; Preferably, the pre-mixing and blending process is carried out in a ball mill or a blender; preferably, the pre-mixing and blending process is performed by using a self-rotating and revolving blender having a revolution speed ≥ 20 rpm, independently preferably 30-90 rpm, and an autorotation speed ≥ 200 rpm, independently preferably 500-2,000 rpm; preferably, the pre-mixing is performed for 0.5-4h, preferably 1-2h; Preferably, the dew point is ≤ -45° C., further preferably ≤ -60° C.
28. A method for improving the safety performance of a lithium battery compring: adding oxide solid electrolyte particles having a particle diameter D50 within a range of 0.1-3 .Math.m and dispersing the oxide solid electrolyte particles between anode active material particles during the preparation process, the positive piece has an area capacity larger than or equal to 4mAh/cm.sup.2.
29. A lithium battery comprising the positive piece of any one of claims 21-25.
30. The lithium battery of claim 29, wherein the lithium battery comprises a liquid lithium battery or a semi-solid lithium battery; preferably, the liquid lithium battery comprises the positive piece of any one of claims 21-25, a negative piece and a liquid electrolyte; preferably, the semi-solid lithium battery comprises the positive piece of any one of claims 21-25, a negative piece and an electrolyte layer containing a liquid electrolyte.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0136]
[0137]
[0138]
[0139]
[0140] 1-ternary positive piece; 10-aluminum foil; 11-anode active material; 12-oxide solid electrolyte; 2-negative piece; 20-copper foil; 21-cathode active material; 3-solid electrolyte, liquid electrolyte or semi-solid electrolyte, wherein the liquid lithium-ion battery further comprises a diaphram;
[0141]
[0142]
[0143]
DETAILED DESCRIPTION
[0144] The technical solutions of the present disclosure will be clearly and completely described below with reference to the examples of the present disclosure. Obviously, the described examples are only part of the embodiments of the invention, instead of covering all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by the ordinary skilled person in the art without paying a creative labor fall into the protection scope of the present disclosure.
[0145] The technical solution of the present disclosure is further described by using the specific embodiments below. It should be understood by those skilled in the art that the examples merely serve to facilitate comprehension of the present disclosure, shall not be regarded as imposing the specific limitation to the present disclosure.
Comparative Example 1
[0146] In the Comparative Example 1, a lithium-rich compound was not mixed in the positive piece; the anode active material in the positive piece was LiNi.sub.0.83Co.sub.0.12Mn.sub.0.05O.sub.2(Ni83), the binder was PVDF, and the conductive agent was CNT; a mass ratio of the anode active material, the binder and the conductive agent was 95:2:3, the preparation method of the positive piece was composed of the following steps:
[0147] A glue solution was uniformly mixed with Ni83, the conductive agent was added to form an anode sizing agent, which was then coated on an aluminum foil, and then subjected to baking, cold pressing and tabletting to prepare an positive piece, the produced positive piece had an area capacity of 5.4 mAh/cm.sup.2.
[0148] The well-designed negative piece (with an active material SiC) was assembled and welded with ceramic diaphrams each having a thickness of 15 .Math.m and a porosity of 50%, and subjected to hi-pot test and packaging, and then subjected to baking, the injected lithium salt was LiPF.sub.6, the solvent was a mixed solvent of ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate, the additive was VC electrolyte; the encapsulation, formation and capacity separation process was performed after the injection, the battery was fabricated.
Example 1
[0149] In the Example, a lithium-rich manganese-based solid solution was doped and mixed in the positive piece; the lithium-rich manganese-based solid solution was 0.5Li.sub.2MnO.sub.3 .Math. 0.5LiMn.sub.0.54Ni.sub.0.13Co.sub.0.13O.sub.2, the mass ratio of the anode active material to the lithium-rich compound was 94:6; the particle diameter of the lithium-rich compound was 500 nm; the anode active material in the positive piece was Ni83, the binder was PVDF, and the conductive agent was CNT; and the method of preparing the positive piece comprising the following steps: [0150] the anode active material was premixed with the lithium-rich compound nanoparticles for 1 h in advance at a revolution speed of 40 r/min and a dispersion rotation speed of 500 r/min to obtain a premixed powder; [0151] a glue solution was added to the premixed powder according to the mass ratio of premixed powder: binder: conductive agent of 95:2:3, the materials were uniformed mixed and then added with the conductive agent to prepare an anode sizing agent; which was then coated on an aluminum foil, and then subjected to baking, cold pressing and tabletting to prepare an positive piece, the positive piece had an area capacity of 5.4 mAh/cm.sup.2.
[0152] The well-designed negative piece (with an active material SiC) was assembled and welded with ceramic diaphrams each having a thickness of 15 .Math.m and a porosity of 50%, and subjected to hi-pot test and packaging, and then subjected to baking, the injected lithium salt was LiPF.sub.6, the solvent was a mixed solvent of ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate, the additive was VC electrolyte; the encapsulation, formation and capacity separation process was performed after the injection, the battery was fabricated.
Example 2
[0153] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich manganese-based solid solution was 90:10; the lithium-rich manganese-based solid solution was 0.37Li.sub.2MnO.sub.3.Math.0.63LiNi.sub.0.13Co.sub.0.13Mn.sub.0.54O.sub.2, the particle diameter of the lithium-rich manganese-based solid solution was 2 .Math.m, the other parameters and conditions were completely identical to those in Example 1.
Example 3
[0154] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich solid electrolyte was 99.5:0.5, the particle diameter of the particles of the lithium-rich solid electrolyte was 200 nm, and the lithium-rich solid electrolyte was Li.sub.7La.sub.3ZrO.sub.2, the other parameters and conditions were completely identical to those in Example 1.
Example 4
[0155] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich solid electrolyte was 92:8, the particle diameter of the lithium-rich solid electrolyte was 2 .Math.m, and the lithium-rich solid electrolyte was L1.sub.6.75La.sub.3Zr.sub.1.75Ta.sub.0.25O.sub.12, with other parameters and conditions were identical to those in Example 1.
Example 5
[0156] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich delithiated compound was 99.5:0.5, the particle diameter of the lithium-rich delithiated compound was 200 nm, the lithium-rich delithiated compound was Li.sub.1.4SiO.sub.0.9, the other parameters and conditions were completely identical to those in Example 1.
Example 6
[0157] This Example differed from Example 1 in that the anode active material was LiNi.sub.0.8Co.sub.0.1Al.sub.0.1O.sub.2, the lithium-rich delithiated compound was Li.sub.2.1SiO, the mass ratio of the anode active material to the lithium-rich delithiated compound was 95:5, the particle diameter of the lithium-rich delithiated compound was 1 .Math.m; the other parameters and conditions were completely identical to those in Example 1.
Example 7
[0158] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich solid electrolyte was 94:6, the particle diameter of the lithium-rich solid electrolyte was 500 nm, the lithium-rich solid electrolyte was Li.sub.7La.sub.3Zr.sub.2O.sub.12, the other parameters and conditions were completely identical to those in Example 1.
Example 8
[0159] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich delithiated compound was 94:6; the particle diameter of the lithium-rich delithiated compound was 500 nm; the lithium-rich delithiated compound was Li.sub.1.4SiO.sub.0.9; the other parameters and conditions were completely identical to those in Example 1.
Example 9
[0160] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich manganese-based solid solution was 94:6; the particle diameter of the lithium-rich lithium manganese-based solid solution was 10 .Math.m; the lithium-rich manganese-based solid solution was 0.5Li.sub.2MnO.sub.3 0.5LiMn.sub.0.54Ni.sub.0.13Co.sub.0.13O.sub.2, the other parameters and conditions were completely identical to those in Example 1.
Example 10
[0161] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich manganese-based solid solution was 94:6; the particle diameter of the lithium-rich lithium manganese-based solid solution was 100 nm; the lithium-rich manganese-based solid solution was 0.5Li.sub.2MnO.sub.3 0.5LiMn.sub.0.54Ni.sub.0.13Co.sub.0.13O.sub.2; the other parameters and conditions were completely identical to those in Example 1.
Example 11
[0162] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich manganese-based solid solution was 99:1; the particle diameter of the lithium-rich manganese-based solid solution was 500 nm; the lithium-rich manganese-based solid solution was 0.5Li.sub.2MnO.sub.3 0.5LiMn.sub.0.54Ni.sub.0.13Co.sub.0.13O.sub.2, the other parameters and conditions were completely identical to those in Example 1.
Example 12
[0163] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich manganese-based solid solution was 95:5; the particle diameter of the lithium-rich manganese-based solid solution was 500 nm; the lithium-rich manganese-based solid solution was 0.5Li.sub.2MnO.sub.3 0.5LiMn.sub.0.54Ni.sub.0..sub.13Co.sub.0.13O.sub.2; the other parameters and conditions were completely identical to those in Example 1.
Example 13
[0164] This Example differed from Example 1 in that the mass ratio of the anode active material to the lithium-rich delithiated compound was 80:20; the particle diameter of the lithium-rich delithiated compound was 500 nm; the lithium-rich delithiated compound was Li.sub.1.6SiO.sub.1.1, the other parameters and conditions were completely identical to those in Example 1.
Example 14
[0165] This Example differed from Example 5 in that the mass ratio of the anode active material to the lithium-rich delithiated compound was 99.5:0.5, the particle diameter of the lithium-rich delithiated compound is 200 nm, the lithium-rich delithiated compound was Li.sub.2.1SiO, the other parameters and conditions were completely identical to those in Example 5.
[0166] Tests were conducted on batteries assembled from positive pieces obtained from Comparative Example 1 and Examples 1-14;
[0167] 1. Cycle test: the energy density of 15 Ah batteries of Comparative Example 1 and Examples 1, 3 and 5 at high area capacity reached 300 Wh/Kg, the batteries were subjected to the cycle performance test, and the test continued when the cell discharge capacity percentage was larger than 80%, otherwise the test was stopped; the test results were shown in
[0168] 2. Piercing test: 15 Ah batteries had an energy density larger than or equal to 300 Wh/Kg, test conditions comprised: a diameter φ of the needle was within a range of 3-8 mm, piercing rate was 25-80 mm/s; the battery core was pierced vertically, the needle was retained in the battery for 1 h, the battery was denoted as passing the test if there was “no fire, no explosion”, otherwise the test result was failed.
TABLE-US-00001 Scheme Energy density Wh/Kg Result Voltage before the test /V Voltage after the test /V Maximum temperature of battery surface /°C Comparative Example 1 304 Failed 4.176 0 426.3 Example 1 303 Passing 4.180 3.955 52.8 Example 2 302 Passing 4.178 3.838 50.9 Example 3 302 Passing 4.175 4.121 38.8 Example 4 301 Passing 4.177 4.107 37.5 Example 5 302 Passing 4.175 3.556 43.1 Example 6 303 Passing 4.178 4.088 45.2 Example 7 301 Passing 4.175 4.100 44.3 Example 8 302 Passing 4.179 4.025 52.4 Example 9 302 Passing 4.173 3.876 55.5 Example 10 302 Passing 4.176 3.525 53.7 Example 11 303 Passing 4.178 4.001 62.1 Example 12 302 Passing 4.176 3.778 59.0 Example 13 296 Passing 4.175 4.038 35.9 Example 14 303 Passing 4.179 3.661 60.6
[0169] As can be seen from the above Table 1, the energy density of the battery comprising an anode added with the lithium-rich compound was larger than 300 Wh/Kg, the battery can pass the piercing test, and the change of surface temperature after the piercing test was not obvious; when the added amount of the lithium-rich compound was 20%, the energy density of the battery was reduced significantly; in contrast, the battery without adding the lithium-rich compound cannot pass the piercing test.
[0170] 3: Thermal shock test: 15 Ah batteries had an energy density larger than or equal to 300 Wh/Kg, the batteries were subjected to heating at 190° C. for 2 h; the temperature rise rate was 5° C./min, the temperature was raised to 190° C. and preserve for 2 h, and then observed for 1 h; the battery was denoted as passing the test if there was “no fire, no explosion”, otherwise the test result was failed; the test results were shown in Table 2;
TABLE-US-00002 Scheme Energy density Wh/Kg Result Voltage before the test /V Comparative Example 1 304 Failed 4.176 Example 1 302 Passing 4.180 Example 2 301 Passing 4.178 Example 3 303 Passing 4.175 Example 4 302 Passing 4.177 Example 5 302 Passing 4.175 Example 6 302 Passing 4.178 Example 7 301 Passing 4.176 Example 8 301 Passing 4.168 Example 9 302 Passing 4.171 Example 10 301 Passing 4.158 Example 11 303 Passing 4.163 Example 12 302 Passing 4.152 Example 13 294 Passing 4.177 Example 14 302 Passing 4.168
[0171] As can be seen from Table 2 above, the energy density of the battery comprising an anode added with the lithium-rich compound was larger than 300 Wh/Kg, the battery can pass the thermal shock test at 190° C. for 2 h; the energy density of the battery was reduced significantly when the added amount of the lithium-rich compound was 20%; in contrast, the battery cell without adding the lithium-rich compound cannot pass the thermal shock test at 190° C.
[0172] The present disclosure can significantly improve the safety performance of high energy density batteries by doping and mixing a lithium-rich compound into a high nickel ternary positive piece. The energy density of the batteries of Comparative Example 1 and Examples 1, 3 and 5 can reach 300 Wh/Kg; the batteries of Examples 1, 3 and 5 added with different lithium-rich compound can pass the piercing test, the change of surface temperature of the batteries was not obvious; the batteries passed the thermal shock test at 190° C. for 2 h, the reasons mainly resides in that the lithium-rich compound can pull away Lithium-ions under the extreme conditions, thereby filling in lithium vacancies in the anode material, stabilizing the crystal lattice structure of the anode material, stabilizing the content of lithium in the anode, decreasing the oxidation state of the anode under the extreme conditions, and enhancing the safety performance of the battery prepared therefrom under the extreme conditions;
[0173] Examples 9, 10 and 1 were compared to illustrate the influence of adding different particle diameters on the safety performance of the batteries, the desirable effect of improving safety performance of the battery cannot be produced if the particle diameter of the lithium-rich compound doped into the anode was too small or too large; when the particle diameter of the lithium-rich compound was too small, the interface resistance was increased, such that the ion transport was blocked; when the particle diameter was too large, its effect of separating the anode particles was not obvious, thus the safety performance of the battery was not significantly improved.
[0174] Examples 5 and 13 were compared to demonstrate an influence of the added amount of the lithium-rich compound on the safety performance of the battery; if the added amount was too small, the improvement of the safety performance was not obvious; if the added amount was too large, the safety performance of battery can be improved, but the reduced amount of active material particles in the positive piece will slightly lower the energy density of the battery, the energy density of the battery of Example 13 was lowered to 294 Wh/Kg.
[0175] As can be seen from the comparison result of Examples 1, 7 and 8, under the condition that the mixed amounts were the same, the battery prepared by doping and mixing with lithium-rich solid electrolyte showed superior safety performance, the maximum temperature of the battery surface is the lowest during a process of subjecting to the piercing test.
[0176]
[0177]
Comparative Example 2
[0178] In the Comparative Example 2, the current collector in the ternary positive piece was aluminum foil, the anode active material was Ni.sub.83CLiNi.sub.0.83Co.sub.0.11Mn.sub.0.06O.sub.2), the oxide solid electrolyte was LATP (Li.sub.1.4Al.sub.0.4Ti.sub.1.6(PO.sub.4).sub.3) with a solid spherical shape, the mass ratio of he anode active material to the oxide solid electrolyte was 97:3, the particle diameter of the oxide solid electrolyte was 0.8 pm; the area capacity of the ternary positive piece was larger than or equal to 4mAh/cm.sup.2, the method of preparing the ternary positive piece comprises the following steps: [0179] Ni83 was pre-mixed with LATP nanoparticles for 0.5 h in advance at the revolution speed of 40 r/min and a dispersion rotation speed of 1,500 r/min to obtain a premixed powder; [0180] The pre-mixed powder was added with a glue solution and uniformly mixed, then added with a conductive agent according to a mass ratio of the pre-mixed powder: the binder (PVDF): the conductive agent (CNT) being 95:2:3, so as to produce an anode sizing agent; [0181] the anode sizing agent was then coated on the aluminum foil; the coated aluminum foil was subjected to baking and cold compressing, and then tailored into a ternary positive piece.
[0182] Preparation of the negative piece: cathode powder: a cathode sizing agent was prepared by mixing a conductor (Sp), CMC and SBR according to a mass ratio of 95.8:1:1.2:, the cathode sizing agent was coated on a copper foil, the coated copper foil was subjected to baking and cold compressing, and subsequently tailored into a negative piece. The cathode powder was SL450A-SOC nanometer silicon carbon cathode material manufactured by the Liyang Tianmu Pioneer Battery Material Technology Co., Ltd.
[0183] The well-designed negative piece and ceramic diaphram (base film PP coating layer was Al.sub.2O.sub.3) were assembled and welded, and subjected to hi-pot test, sealing the top and the sides and then baking, and subjected to the complete encapsulation after an injection of electrolyte (the electrolyte was EC+DEC+FEC+LiPF.sub.6), formation and capacity separation process, and lithium battery was fabricated and then subjected to electrical performance and safety testing, and the test results were shown in Table 3;
TABLE-US-00003 Test items Results Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 300 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3C rate discharge ≥80% / / 58 Piercing Passing 4.176 3.863 56 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 192 Rate 5° C./min 50% deformation compression Passing 4.175 3.887 48 Rate 2 mm/s
[0184] As can be seen from Table 3, the present disclosure improved the safety performance of the batteries by blending the oxide solid electrolyte in the high nickel ternary positive piece, the 15 Ah batteries can meet the energy density of 300 Wh/kg at the charging and discharging currents of 0.3 C/0.3 C, and the discharge retention rate of the batteries can reach 80% or more at the discharging current rate of 3 C, the safety performance of the batteries can be comprehensively improved, and can pass the piercing test, 180° C. hot box test and 50% deformation compression test, the main reasons resided in that the oxide solid electrolyte was added into the ternary anode active material, it can effectively block the contact between the ternary active particles, and improve the thermal stability of the positive piece; secondly, the oxide solid electrolyte of the present disclosure per se had a certain thermal capacity, can absorb a portion of the heat generated by the anode, alleviate overheating of the anode, and can also improve the safety performance of the battery.
Example 15
[0185] The Example 15 merely differed from the Comparative Example 2 in that the oxide solid electrolyte had a porous spherical shape with a porosity of 50%, and the other parameters and conditions were identical to those in the Comparative Example 2.
[0186] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 4.
TABLE-US-00004 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 307 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥90% / / 55 Piercing Passing 4.175 3.942 53 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 188 Rate 5° C./min 50% deformation compression Passing 4.176 3.987 46 Rate 2 mm/s
[0187] As can be seen from Table 4, in contrast to the Comparative Example 2, the oxide solid electrolyte doped into the high nickel ternary positive piece had a porous spherical shape, the porous spherical solid electrolyte had more reaction sites, can enhance the rate capability of the battery, such that the 3 C rate discharge retention rate of the battery can reach 90% or more, and the energy density of the battery was increased to 305 Wh/kg; in addition, the porous spherical oxide solid electrolyte doped into the anode can absorb more heat generated by the positive piece, thereby favorably improving the thermal stability of the battery, and further enhancing the safety performance of the battery.
Example 16
[0188] This Example differs from Example 15 in that the mass ratio of anode active material to oxide solid electrolyte was 95:5, the other parameters and conditions were completely identical to those in Example 15.
[0189] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 5.
TABLE-US-00005 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 302 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3 C rate discharge ≥83% / / 55 Piercing Passing 4.176 3.953 56 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 187 Rate 5° C./min 50% deformation compression Passing 4.175 3.988 45 Rate 2 mm/s
[0190] As can be seen from Table 5, the content of the solid electrolyte of the Example 16 in the anode is increased to 5% in comparison with Example 15, although the safety performance can be slightly increased, the energy density of the battery was remarkably decreased, and the 3 C rate performance of the battery was also decreased from 90% to 83%, the reason resided in that the proportion of active materials in the anode material was decreased along with an increase of the solid electrolyte, thus the energy density of the battery was reduced, and the rate performance of the battery was also deteriorated.
Example 17
[0191] This Example differed from Example 15 in that the oxide solid electrolyte LATP was replaced with LAGP (Li.sub.1.5Al.sub.0.5Ge.sub.1.5(PO.sub.4).sub.3), the morphology of LAGP was porous and spherical, the other parameters and conditions were completely identical to those in Example 15.
[0192] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 6.
TABLE-US-00006 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 300 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥89% / / 59 Piercing Passing 4.175 3.982 55 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 189 Rate 5° C./min 50% deformation compression Passing 4.176 3.992 45 Rate 2 mm/s
[0193] As can be seen from Table 6, compared with Example 15, the porous spherical solid electrolyte LATP of the Example 17 was replaced with LAGP, the energy density of the battery cell was slightly reduced, and the rate-discharge performance was slightly decreased, the reason resided in that the electrical conductivity of LAGP is slightly inferior to LATP, thus the properties of the battery were slightly decreased.
Example 18
[0194] This Example merely differed from Example 15 in that the dispersion rotational speed during the pre-mixing process was 500 r/min, the other parameters and conditions were completely identical to those in Example 15.
[0195] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 7.
TABLE-US-00007 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 307 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥89% / / 56 Piercing Passing 4.173 3.933 54 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 190 Rate 5° C./min 50% deformation compression Passing 4.173 3.964 48 Rate 2 mm/s
[0196] As can be seen from Table 7, the dispersing rotational speed during the premixing process of Example 18 was reduced to 500 r/min from 1,500 r/min in Example 15, the oxide solid electrolyte can be uniformly dispersed along with the decrease of the rotational speed, but the energy density and rate performance of the battery were substantially unaffected.
Example 19
[0197] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 2 .Math.m, the other parameters and conditions were completely identical to those in Example 15.
[0198] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 8.
TABLE-US-00008 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 306 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥88% / / 56 Piercing Passing 4.173 3.934 54 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 191 Rate 5° C./min 50% deformation compression Passing 4.175 3.976 47 Rate 2 mm/s
[0199] As can be seen from Table 8, compared with Example 15, the particle diameter of the oxide solid electrolyte changed from 0.8 pm to 2 .Math.m, the particle diameter was significantly increased, the energy density and rate performance of the battery were substantially unchanged, and the piercing performance was not significantly changed.
Example 20
[0200] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 0.5 .Math.m, the other parameters and conditions were completely identical to those in Example 15.
[0201] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 9.
TABLE-US-00009 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 306 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥86% / / 58 Piercing Passing 4.173 3.930 55 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 189 Rate 5° C./min 50% deformation compression Passing 4.174 3.963 48 Rate 2 mm/s
[0202] As can be seen from Table 9, in comparison with Example 15, the particle diameter of the oxide solid electrolyte of the Example was changed from 0.8 pm to 0.5 .Math.m, the particle diameter of the solid electrolyte was decreased, the energy density and rate performance of the battery were substantially unchanged, and the safety performance of the battery was substantially consistent with that in Example 15.
Example 21
[0203] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 3 .Math.m, the other parameters and conditions were completely identical to those in Example 15.
[0204] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 10.
TABLE-US-00010 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 306 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3 C rate discharge ≥88% / / 58 Piercing Passing 4.173 3.912 56 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 189 Rate 5° C./min 50% deformation compression Passing 4.175 3.932 48 Rate 2 mm/s
[0205] As can be seen from Table 10, in comparison with Example 15, the particle diameter of the oxide solid electrolyte of the present example was changed from 0.8 pm to 3 .Math.m, the energy density and rate performance of the battery were substantially consistent with those of Example 15, and the safety performance was not significantly lowered.
Example 22
[0206] This Example differed from Example 15 in that the mass ratio of the anode active material to the oxide solid electrolyte was 99.9:0.1, the other parameters and conditions were completely identical to those in Example 15;
[0207] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 11.
TABLE-US-00011 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 310 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3 C rate discharge ≥92% / / 60 Piercing Failed 4.175 / / φ5 mm, 40 mm/s Heating at 180° C. for 2 h Failed / / / Rate 5° C./min 50% deformation compression Passing 4.176 3.876 65 Rate 2 mm/s
[0208] As can be seen from Table 11, compared with Example 15, the content of the solid electrolyte in the anode material of the Example was reduced to 0.1%, the other parameters were not changed, the energy density of the battery was significantly increased, and the rate performance was also slightly improved, but the battery safety performance including the piercing test and the hot box test of 180° C. was substantially failed, the reasons resided in that the content of the oxide solid electrolyte was reduced, the contact between the ternary active particles could not be effectively blocked, and a portion of the heat generated by the anode cannot be absorbed, resulting in the deterioration of the safety performance of the battery.
Example 23
[0209] This Example differed from Example 15 in that the mass ratio of the anode active material to the oxide solid electrolyte was 90:10, the other parameters and conditions were completely identical to those in Example 15;
[0210] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 12.
TABLE-US-00012 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 290 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,000 cycles / / / 1 C/1 C 3 C rate discharge ≥75% / / 53 Piercing Passing 4.175 3.999 50 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 185 Rate 5° C./min 50% deformation compression Passing 4.176 3.998 43 Rate 2 mm/s
[0211] As can be seen from Table 12, in comparison with Example 15, the content of the solid electrolyte in the anode material of the Example was increased to 10%, the energy density of the battery was significantly decreased, the cycle number was decreased, and the rate performance was deteriorated, the reason resided in that the percentage of the anode active material was decreased due to the high content of the solid electrolyte, such that the electrochemical performance of the battery was deteriorated.
Example 24
[0212] This Example differed from Example 15 in that the oxide solid electrolyte LATP in Example 15 was replaced with LLTO (Li.sub.0.5La.sub.0.5TiO.sub.3), the morphology of LLTO was porous and spherical, the other parameters and conditions were completely identical to those in Example 15.
[0213] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 13.
TABLE-US-00013 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 306 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥91% / / 54 Piercing Passing 4.176 3.943 53 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 189 Rate 5° C./min 50% deformation compression Passing 4.175 3.986 45 Rate 2 mm/s
[0214] As can be seen from Table 13, compared with Example 15, the solid electrolyte was changed from LATP to LLTO, the electrochemical performance and safety performance of the battery cell were not significantly changed, because the properties of the two materials were basically consistent.
Example 25
[0215] This Example differed from Example 15 in that the oxide solid electrolyte LATP was replaced with LZGO (Li.sub.14ZnGe.sub.4O.sub.16), the morphology of the LZGO was porous and spherical, the other parameters and conditions were completely identical to those in Example 15.
[0216] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 14.
TABLE-US-00014 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 295 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3 C rate discharge ≥78% / / 60 Piercing Passing 4.174 3.643 56 φ5 mm, 40 mm/s Heating at 180° C. for 2 h Passing / / 194 Rate 5° C./min 50% deformation compression Passing 4.170 3.882 47 Rate 2 mm/s
[0217] As can be seen from Table 14, compared with Example 15, the oxide solid electrolyte LATP was replaced with LZGO, the kind of solid electrolyte was altered, the energy density of the battery was remarkably lowered, 3C rate discharge performance was deteriorated, and the safety performance of the battery was also obviously deteriorated, the reasons resided in that LZTO had a large ionic conductivity, such that the impedance of the positive piece was large, resulting in poor battery performance.
Example 26
[0218] This Example differed from Example 15 in that the oxide solid electrolyte LATP was replaced with LLZO (Li.sub.7La.sub.3ZrO.sub.2), the morphology of LLZO was porous and spherical, the other parameters and conditions were completely identical to those in Example 15.
[0219] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 15.
TABLE-US-00015 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 302 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥81% / / 56 Piercing Passing 4.174 3.810 52 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing 4.171 3.710 194 Rate 5° C./min 50% deformation compression Passing 4.172 3.987 50 Rate 2 mm/s
[0220] As can be seen from Table 15, compared with Example 15, the oxide solid electrolyte LATP was changed to LLZO, the kind of solid electrolyte was changed, the energy density of the cell was reduced, the 3C rate discharge performance was deteriorated, and the ionic conductivity of LLZO was slightly reduced as compared with LATP, thereby leading to deterioration of the cell performance.
Example 27
[0221] This Example differed from Example 15 in that the porosity of the porous spherical oxide solid electrolyte was replaced by 40%, the other parameters and conditions were completely identical to those in Example 15.
[0222] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 16.
TABLE-US-00016 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 306 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥89% / / 56 Piercing Passing 4.173 3.940 54 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing 4.172 3.840 189 Rate 5° C./min 50% deformation compression Passing 4.173 3.980 48 Rate 2 mm/s
[0223] As can be seen from Table 16, compared with Example 15, the porosity of the oxide solid electrolyte LATP was changed from 50% to 40%, the energy density and rate capability of the battery cell were substantially unchanged.
Example 28
[0224] This Example differs from Example 15 in that the porosity of the porous spherical oxide solid electrolyte was replaced by 5%, the other parameters and conditions were completely identical to those in Example 15.
[0225] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 17.
TABLE-US-00017 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 301 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥82% / / 57 Piercing Passing 4.173 3.901 55 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing 4.172 3.766 191 Rate 5° C./min 50% deformation compression Passing 4.173 3.890 48 Rate 2 mm/s
[0226] As can be seen from Table 17, compared with Example 15, the porosity of the oxide solid electrolyte LATP was changed from 50% to 5%, the porosity was reduced, the active sites for reaction were decreased accordingly, the energy density and rate performance of the battery cell were slightly deteriorated, and the capacity to absorb heat generated from the anode was deteriorated due to the smaller porosity, thereby resulting in that the safety performance was also deteriorated to some extent.
Example 29
[0227] This Example differs from Example 15 in that the mass ratio of the anode active material to the oxide solid electrolyte was 99.99:0.01, the other parameters and conditions were completely identical to those in Example 15.
[0228] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 18.
TABLE-US-00018 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 311 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥93% / / 60 Piercing Failed 4.175 / / φ5 mm,40 mm/s Heating at 180° C. for 2 h Failed / / / Rate 5° C./min 50% deformation compression Failed 4.176 / / Rate 2 mm/s
[0229] As can be seen from Table 18, compared with Example 15, the content of the solid electrolyte in the anode material of the Example was reduced to 0.01%, the other parameters were unchanged, the energy density of the battery was significantly increased, and the rate performance was slightly increased, but the battery cannot pass the safety performance test, the reason resided in that the content of the oxide solid electrolyte was reduced, the contact between the ternary active particles cannot be effectively blocked, and the heat generated at the anode could not be absorbed, such that the safety performance of the battery was deteriorated.
Example 30
[0230] This Example differed from Example 15 in that the mass ratio of the anode active material to the oxide solid electrolyte was 85:15, the other parameters and conditions were completely identical to those in Example 15.
[0231] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 19.
TABLE-US-00019 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 280 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,000 cycles / / / 1C/1C 3 C rate discharge ≥60% / / 53 Piercing Passing 4.175 4.102 49 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing / / 184 Rate 5° C./min 50% deformation compression Passing 4.176 4.101 42 Rate 2 mm/s
[0232] As can be seen from Table 19, compared with Example 15, the content of the solid electrolyte in the anode material of the Example was increased to 15%, the energy density of the battery cell was significantly reduced, both the cycle number and rate performance of the battery cell were significantly deteriorated, the reasons resided in that the high content of the solid electrolyte caused a reduced percentage of the anode active material, thereby resulting in a deterioration of the electrochemical performance of the battery.
Example 31
[0233] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 0.1 .Math.m,the other parameters and conditions were completely identical to those in Example 15.
[0234] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 20.
TABLE-US-00020 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 303 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥83% / / 59 Piercing Passing 4.173 3.920 54 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing / / 190 Rate 5° C./min 50% deformation compression Passing 4.174 3.943 49 Rate 2 mm/s
[0235] As can be seen from Table 20, in comparison with Example 15, the particle diameter of the oxide solid electrolyte of the Example was changed from 0.8 pm to 0.1 .Math.m,the particle diameter of the solid electrolyte was reduced, the energy density and rate performance of the battery cell were decreased to some extent, the safety performance of the battery cell was substantially consistent with that of Example 15.
Example 32
[0236] This Example differed from Example 15 in that the oxide solid electrolyte had a particle diameter of 0.01 .Math.m,the other parameters and conditions were completely identical to those in Example 15.
[0237] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 21.
TABLE-US-00021 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 293 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1C/1C 3 C rate discharge ≥78% / / 59 Piercing Failed 4.172 / / φ5 mm,40 mm/s Heating at 180° C. for 2 h Failed / / / Rate 5° C./min 50% deformation compression Failed 4.174 / / Rate 2 mm/s
[0238] As can be seen from Table 21, in comparison with Example 15, the particle diameter of the oxide solid electrolyte of the Example was changed from 0.8 pm to 0.01 .Math.m, the particle diameter of the solid electrolyte was decreased, the energy density and rate performance of the battery cell were substantially lowered, and the safety performance of the battery cell was also obviously deteriorated, mainly because the particles were smaller, the agglomeration phenomenon can be easily generated, thereby deteriorating the electrochemical performance and safety performance of the battery cell.
Example 33
[0239] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 11 .Math.m, the other parameters and conditions were completely identical to those in Example 15.
[0240] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 22.
TABLE-US-00022 Test items Result Voltage before the test /V Voltage after the test /V Temperature/°C Remark (test conditions) Energy density 285 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,100 cycles / / / 1 C/1 C 3 C rate discharge ≥77% / / 54 Piercing Failed 4.173 / / φ5 mm,40 mm/s Heating at 180° C. for 2 h Failed 4.175 / / Rate 5° C./min 50% deformation compression Passing 4.175 3.976 47 Rate 2 mm/s
[0241] As can be seen from Table 22, compared with Example 15, the particle diameter of the oxide solid electrolyte was changed from 0.8 .Math.m to 11 .Math.m, the particle diameter of the oxide solid electrolyte was significantly increased, the energy density of the battery was significantly deteriorated, the cycle performance was slightly degraded, and the rate performance of the battery cell was also significantly lowered, because the particle diameter of the solid electrolyte was increased, the increased resistance of the material caused deterioration of the battery properties; in addition, the safety performance of the battery was significantly lowered, because the particle diameter of the oxide solid electrolyte was increased, its effect of blocking contact between the particles of anode was not significant, thus the contact between the ternary active particles cannot be effectively obstructed, affecting the safety performance of the battery cell.
Example 34
[0242] This Example differed from Example 15 in that the particle diameter of the oxide solid electrolyte was 10 .Math.m, the other parameters and conditions were completely identical to those in Example 15.
[0243] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 23.
TABLE-US-00023 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 300 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥85% / / 54 Piercing Passing 4.173 3.910 55 (φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing 4.175 / / Rate 5° C./min 50% deformation compression Passing 4.175 3.976 47 Rate 2 mm/s
[0244] As can be seen from Table 23, compared with Example 15, the particle diameter of the oxide solid electrolyte was changed from 0.8 .Math.m to 10 .Math.m, the particle diameter was enlarged, causing deterioration of the energy density and rate performance of the battery cell, but the battery cell can still pass the safety performance test.
Example 35
[0245] This Example differed from Example 15 in that the porosity of the porous spherical oxide solid electrolyte was replaced with 3%, the other parameters and conditions were completely identical to those in Example 15.
[0246] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 24.
TABLE-US-00024 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 300 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥81% / / 57 Piercing Passing 4.173 3.842 55 φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing / / 191 Rate 5° C./min 50% deformation compression Passing 4.173 3.873 48 Rate 2 mm/s
[0247] As can be seen from Table 24, compared with Example 15, the porosity of the oxide solid electrolyte LATP was changed from 50% to 3%, the porosity was decreased, the active sites for reaction were significantly reduced, resulting in the decreased energy density of the battery cell, and degraded rate performance of the battery cell; in addition, due to the decreased porosity, the capacity of absorbing heat generated by the anode was reduced, the Lithium-ions transport performance was degraded, and the energy density was slightly decreased.
Example 36
[0248] This Example differed from Example 15 in that the porosity of the porous spherical oxide solid electrolyte was replaced by 70%, the other parameters and conditions were completely identical to those in Example 15.
[0249] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 25.
TABLE-US-00025 Test items Result Voltage before the test IV Voltage after the test IV Temperature /°C Remark (test conditions) Energy density 308 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥90% / / 57 Piercing Passing 4.173 3.945 54 φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing / / 184 Rate 5° C./min 50% deformation compression Passing 4.173 3.973 46 Rate 2 mm/s
[0250] As can be seen from Table 25, compared with Example 15, the porosity of the oxide solid electrolyte LATP was changed to 70% from 50%, the porosity was increased, the active sites for reaction were significantly increased, so that the energy density and rate performance of the battery cell were also improved slightly; in addition, since the porosity was increased, the capacity for absorbing heat generated from the anode was enhanced, the transport performance of Lithium-ions was improved, so that the safety performance of the battery cell can also be increased.
Example 37
[0251] This Example differed from Example 15 in that the porosity of the porous spherical oxide solid electrolyte was replaced by 80%, the other parameters and conditions were completely identical to those in Example 15.
[0252] The test results of the electrical performance and safety performance of the lithium battery obtained in the Example were shown in Table 26.
TABLE-US-00026 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 309 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥91% / / 57 Piercing Passing 4.173 3.946 54 φ5 mm,40 mm/s Heating at 180° C. for 2 h Passing / / 184 Rate 5° C./min 50% deformation compression Passing 4.173 3.974 46 Rate 2 mm/s
[0253] As can be seen from Table 26, compared with Example 15, the porosity of the oxide solid electrolyte LATP was changed from 50% to 80%, the porosity was increased, the active sites for reaction were significantly increased, thus the energy density and rate performance of the battery cell were slightly improved; moreover, since the porosity was increased, the capacity of absorbing heat generated from the anode was enhanced, the Lithium-ions transport performance was improved, so that the safety performance the battery cell can also be improved; however, during a pore-forming process, the manufacturing process of the material was relatively difficult, and an excessively large porosity of the material caused the finished product ratio of the material was sharply reduced.
Comparative Example 3
[0254] The Comparative Example differs from Example 15 in that the oxide solid electrolyte was not added into the ternary positive piece, the other parameters and conditions were completely identical to those in Example 15.
[0255] The test results of the electrical performance and safety performance of the lithium battery obtained in the Comparative Example were shown in Table 27.
TABLE-US-00027 Test items Result Voltage before the test /V Voltage after the test /V Temperature /°C Remark (test conditions) Energy density 312 Wh/Kg / / / 15 Ah(0.3 C/0.3 C) Cycles 1,200 cycles / / / 1 C/1 C 3 C rate discharge ≥93% / / 60 Piercing Failed 4.175 / / φ5 mm,40 mm/s Heating at 180° C. for 2 h Failed 4.173 / / Rate 5° C./min 50% deformation compression Failed 4.176 / / Rate 2 mm/s
[0256] As can be seen from Table 27, compared with Example 15, the solid electrolyte was not added in the Comparative Example 3, the energy density of the battery cell was slightly increased, and the rate performance was increased to some extent, but the battery did not pass the safety performance of the battery comprising the piercing test, the 180° C. hot box test, and substantially 50% of the deformation compression test, the reasons resided in that the oxide solid electrolyte was not contained, the contact between the ternary active particles cannot be blocked, and the heat generated by the anode cannot be absorbed, thereby causing deterioration of the safety performance of the battery cell.
[0257] As can be seen from the comparison result of Examples 15-37 and Comparative Examples 2-3, the oxide solid electrolyte was added into the ternary positive piece according to the present disclosure, the safety performance of the lithium battery obtained therefrom was remarkably improved, each of the lithium batteries in the Examples can pass the piercing test, the test of heating at 180° C. for 2 h, and the test of 50% deformation compression; and the lithium battery obtained therefrom had a high specific capacity, which may be 300 Wh/Kg or more.
[0258] As can be seen from the comparison result between Comparative Example 2 and Example 15, the present disclosure adopted a porous spherical oxide solid electrolyte, the lithium batteries obtained therefrom had higher capacity and more desirable cycle performance.
[0259] As can be seen from the comparison result of Examples 15, 17 and 24-26, the oxide solid electrolytes were preferably LATP and LLTO.
[0260] As can be seen from the comparison result of Examples 15, 16, 22, 23, 29 and 30, the percentage content by mass of the oxide solid electrolyte was 0.1-10%, preferably 1-5%, based on the sum 100% of the mass of the anode active material and the mass of the oxide solid electrolyte; if the content of the solid electrolyte was too much, the content of the anode active material was decreased, the energy density and electrochemical performance of the battery cell were affected; if the content of the solid electrolyte is too small, the safety performance of the battery cannot be pass the test.
[0261] As can be seen from the comparison results of Examples 15, 19-21 and 31-34, the particle diameter of the oxide solid electrolyte was within a range of 0.1-10 .Math.m, preferably 0.5-3 pm; when the particle diameter of the oxide solid electrolyte was less than 0.1 .Math.m, the particle diameter of the oxide solid electrolyte was too small, the interface resistance was increased, such that ion transport was blocked, the interface impedance was increased, the energy density of the battery was decreased; when the particle diameter of the oxide solid electrolyte was larger than 10 .Math.m, the particle diameter was too large, its effect of blocking contact between the anode particles was not obvious, resulting in insignificant increase of the safety performance.
[0262] As can be seen from the comparison results of Examples 15, 27 and 35-37, the porosity of the porous spherical particles of the oxide solid electrolyte was within a range of 5-70%, preferably 40-70%. If the porosity was too small, the active sites of the solid electrolyte were too small, the interface resistance was excessively large, such that the Lithium-ions transport was blocked; if the porosity was too large, the difficulty of pore formation was multiplied, the yield of the material was significantly reduced.
I. Preparation of Ternary Electrode Piece Doped and Mixed With the Oxide Solid Electrolyte
[0263] The ternary anode active material, the oxide solid electrolyte, the conductive agent and the binder were weighted according to the ratio and data listed in C1-C22 and C25-C30 of Tables 28; the ternary anode active material and oxide solid electrolyte were first vacuum pre-mixed in advance to obtain a uniformly dispersed premixed material; the uniformly dispersed premixed material was gradually added with the NMP glue solution of PVDF and uniformly blended; the conductive agents Super-P and CNT were subsequently added gradually and uniformly blended to obtain a ternary anode sizing agent having a certain fluidity; the ternary anode sizing agent was then coated on aluminum foil, and subjected to forced air drying and rolling, the obtained positive pieces were named C1, C2 ... C22, C25-C30, respectively.
[0264] Wherein the conductive agent was carbon nanotubes and conductive carbon black (CNT + Super-P, the mass ratio of carbon nanotubes to conductive carbon black was 1:2), and the binder was polyvinylidene fluoride (PVDF).
[0265]
II. Preparation of Ternary Positive Piece Without Doping and Mixing With the Oxide Solid Electrolyte
[0266] The ternary anode active material, the conductive agents, and the binder were weighted according to according to the ratio and data listed in C23 and C24 of Table 28; the ternary anode active material was gradually added with the NMP glue solution of PVDF and uniformly blended; the conductive agents Super-P and CNT (according to the mass ratio 1:2 of the CNT and conductive carbon black Super-P) were subsequently added gradually and uniformly blended to obtain a ternary anode sizing agent having a certain fluidity; the ternary anode sizing agent was then coated on aluminum foil, and subjected to forced air drying and rolling, the obtained positive pieces were named C23, C24, respectively.
[0267] Wherein the types of the conductive agent and the binder were identical with those in Example 38, except that the pre-vacuum pre-mixing step was not performed, the other operations were the same as in those in Example 38.
TABLE-US-00028 Ternary electrode sheet parameters of high safety and high capacity No. Oxide solid electrolyte α Ternar Y anode materi al Mass ratio of ternary anode active material, oxide solid electrolyte, conductive agent and binder Pre-mixing time /h Premixing rotation speed / rpm Area capa city of pole piece / mAh/ cm2 .sup.- Types Particle diamete r D50/um Revolut ion Autorot ation C1 LATP-1 0.05 300 Ni80 93:3:2:2 1 40 1,000 4 C2 LATP-1 0.1 150 Ni80 93:3:2:2 1 40 1,000 4 C3 LATP-1 0.5 30 Ni80 93:3:2:2 1 40 1,000 4 C4 LATP-1 1 15 Ni80 93:3:2:2 1 40 1,000 4 C5 LATP-1 2 7.5 Ni80 93:3:2:2 1 40 1,000 4 C6 LATP-1 3 5 Ni80 93:3:2:2 1 40 1,000 4 C7 LATP-1 3.6 4.2 Ni80 93:3:2:2 1 40 1,000 4 C8 LATP-1 1 15 Ni80 95.95:0.05:2:2 1 40 1,000 4 C9 LATP-1 1 15 Ni80 95.9:0.1:2:2 1 40 1,000 4 C10 LATP-1 1 15 Ni80 95:1:2:2 1 40 1,000 4 C11 LATP-1 1 15 Ni80 91:5:2:2 1 40 1,000 4 C12 LATP-1 1 15 Ni80 86:10:2:2 1 40 1,000 4 C13 LATP-1 1 15 Ni80 85:11:2:2 1 40 1,000 4 C14 LATP-1 2 4 Ni80 93:3:2:2 1 40 1,000 4 C15 LATP-1 2 5 Ni80 93:3:2:3 1 40 1,000 4 C16 LATP-1 2 6 Ni80 93:3:2:4 1 40 1,000 4 C17 LLZO-1 2 6 Ni83 92:4:2:2 2 15 150 6 C18 LLZO-1 2 6 Ni83 92:4:2:2 2 30 200 6 C19 LAGP-1 1 15 Ni88 93:3:2:2 1 90 500 10 C20 LZGO 1 15 Ni88 93:3:2:2 4 60 2,000 10 C21 LLTO-1 1 15 NCA 93:3:2:2 0.5 60 1,500 4 C22 LOC 1 15 NCA 93:3:2:2 1.5 80 800 6 C23 / / / Ni80 96:2:2 / / / 4 C24 / / / NCA 96:2:2 / / / 4 C25 LSTZ 1 15 Ni83 93:3:2:2 1.5 50 1,500 6 C26 LATP-2 1 15 Ni83 93:3:2:2 1.5 50 1,500 6 C27 LATP-3 1 15 Ni83 93:3:2:2 1.5 50 1,500 6 C28 LAGP-2 1 15 Ni83 93:3:2:2 1.5 50 1,500 6 C29 LLZO-2 1 15 Ni83 93:3:2:2 1.5 50 1,500 6 C30 LLTO-2 1 15 Ni83 93:3:2:2 1.5 50 1,500 4 Note: α denoted a ratio of the particle diameter D50 of the ternary anode material to the particle diameter D50 of the oxide solid electrolyte.
[0268] The ratio denoted a mass ratio of the ternary anode active material, the oxide solid electrolyte, the conductive agent and the binder.
[0269] The oxide solid electrolyte was Li.sub.1.4Al.sub.0.4Ti.sub.1.6(PO.sub.4).sub.3 (abbreviated as LATP-1), Li.sub.1.3Al.sub.0.3Ti.sub.1.7(PO.sub.4).sub.3 (abbreviated as LATP-2), Li.sub.1..sub.5Al.sub.0.5Ti.sub.1.5(PO.sub.4).sub.3 (abbreviated as LATP-3), Li.sub.6.4La.sub.3Zr.sub.1.6Ta.sub.0.6O.sub.12 (abbreviated as LLZO-1), Li.sub.7La.sub.3Zr.sub.2O.sub.12 (abbreviated as LLZO-2), Li.sub.1.5Al.sub.0.5Ge.sub.1.5(PO.sub.4).sub.3 (abbreviated as LAGP-1), Li.sub.1.3Al.sub.0.3Ge.sub.1.7(PO.sub.4).sub.3 (abbreviated as LAGP-2), Li.sub.0.5La.sub.0.5TiO.sub.s (abbreviated as LLTO-1), Li.sub.0.34La.sub.0.56TiO.sub.3 (abbreviated as LLTO-2), Li.sub.3OCl (abbreviated as LOC), L1.sub.⅜Sr.sub.7/16Ta.sub.¾Zr.sub.¼O.sub.3 (abbreviated as LSTZ), Li.sub.14ZnGe.sub.4O.sub.16 (abbreviated as LZGO).
[0270] The ternary anode material was LiNi.sub.0.8Co.sub.0.1Mn.sub.o.1O.sub.2 (abbreviated as Ni80), LiNi.sub.0..sub.83Co.sub.0..sub.12Mn.sub.0..sub.05O.sub.2 (abbreviated as Ni83), LiNi.sub.0.88Co.sub.0.09Mn.sub.0.03O.sub.2 (abbreviated as Ni88), LiNi.sub.0.8Co.sub.0.15Al.sub.0..sub.05O.sub.2 (abbreviated as NCA).
III. Preparation of Negative Pieces
[0271] In the present disclosure, the cathode may be commonly used graphite, silicon carbon, silica carbon, soft carbon, hard carbon, mesocarbon microspheres and lithium metal complex. The present disclosure did not impose requirements thereon, only if the area capacity matched with the anode during a process of preparing the battery core.
[0272] More specifically, the active substance applied as a main material of the cathode, a conductive agent and a binder were added into deionized water at a mass ratio of 96:2:2 and mixed and stirred uniformly to obtain a cathode sizing agent having a certain fluidity; the cathode sizing agent was then coated on copper foil, and subjected to forced air drying and rolling, the obtained negative pieces were named Al, A2, ... A5, respectively. Wherein the conductive agent was a mixture of carbon nanotube CNT and conductive carbon black Super-P according to a mass ratio of 1:2, and the binder was a mixture of CMC and SBR according to a mass ratio of 1: 1.
TABLE-US-00029 Parameters of the negative piece No. Main material of the cathode Conductive agent Binder Area capacity / mAh/cm.sup.2 A1 silicon carbon CNT+Super-P CMC+SBR 4.4 A2 Silica carbon CNT+Super-P CMC+SBR 6.5 A3 Natural graphite CNT+Super-P CMC+SBR 4.4 A4 silicon carbon CNT+Super-P CMC+SBR 6.5 A5 silicon carbon CNT+Super-P CMC+SBR 11
[0273] The silicon carbon material was SL450A-SOC nanometer silicon carbon cathode material manufactured by the Liyang Tianmu Pioneer Battery Material Technology Co., Ltd., the silica carbon material was S450-2A silica carbon cathode material produced by the BTR New Energy Materials Co., Ltd.
IV. Preparation of Battery Core
[0274] 15Ah soft pouch battery cores were prepared according to the data listed in Table 30, the pole piece sizes: positive electrode (i.e., anode) 107 mm*83 mm, negative electrode (i.e., cathode) 109 mm *85mm.
TABLE-US-00030 Parameters of battery cores No. Anode Cathode Comparative Example 4 Liquid lithium battery C23 A1 Comparative Example 5 Liquid lithium battery C24 A1 Comparative Example 6 Liquid lithium battery C1 A1 Comparative Example 7 Liquid lithium battery C7 A1 Example 38 Liquid lithium battery C2 A1 Example 39 Liquid lithium battery C3 A1 Example 40 Liquid lithium battery C4 A1 Example 41 Liquid lithium battery C5 A1 Example 42 Liquid lithium battery C6 A1 Example 43 Liquid lithium battery C8 A1 Example 44 Liquid lithium battery C9 A1 Example 45 Liquid lithium battery C10 A1 Example 46 Liquid lithium battery C11 A1 Example 47 Liquid lithium battery C12 A1 Example 48 Liquid lithium battery C13 A1 Example 49 Liquid lithium battery C14 A2 Example 50 Liquid lithium battery C15 A2 Example 51 Liquid lithium battery C16 A2 Example 52 Liquid lithium battery C17 A4 Example 53 Liquid lithium battery C18 A4 Example 54 Liquid lithium battery C19 A5 Example 55 Liquid lithium battery C20 A5 Example 56 Liquid lithium battery C21 A3 Example 57 Liquid lithium battery C22 A4 Example 58 Semi-solid lithium battery C4 A1 Example 59 Semi-solid lithium battery C21 A1 Example 60 Liquid lithium battery C25 A4 Example 61 Liquid lithium battery C26 A4 Example 62 Liquid lithium battery C27 A4 Example 63 Liquid lithium battery C28 A4 Example 64 Liquid lithium battery C29 A4 Example 65 Liquid lithium battery C30 A3
[0275] Among them, the Examples 38-57 and 60-65 provided liquid lithium batteries, the diaphram was a double-sided ceramic diaphram, the electrolyte was a commercially conventional electrolyte, wherein the electrolyte of Comparative Examples 4-7 and Examples 38-57 was composed of 1 mol/L LiPF.sub.6-EC/DEC (3:7, V/V) +2 wt% VC +lwt% LiDFOB; the electrolyte of Examples 60-62 was composed of 1.2 mol/L LiPF.sub.6-EC/EMC (3:7, V/V)+2 wt% FEC +1 wt% LiDFOB; the electrolyte of Examples 63-65 was composed of 1.2 mol/L LiPF.sub.6-EC/DEC (3:7, V/V)+2 wt% FEC +1 wt% LiDFOB +1 wt% 1,3-PS; and Examples 58-59 provided semi-solid lithium batteries, which adopted a PVDF-HFP-based gel polymer electrolyte membrane, the electrolyte was consisting of 1 mol/L LiPF.sub.6-EC/DEC (3:7, V/V) +2 wt% VC +1 wt% LiDFOB.
V. Tests of Battery Performance
[0276] The lithium batteries prepared in Examples 38-65 and Comparative Examples 4-7 were subjected to tests of resistance, capacity retention rate after 100 cycles of charging and discharging, and capacity retention rate after 1,000 cycles of charging and discharging, the test results are shown in Table 31. Test voltage range: 2.75-4.2 V, charging and discharging current: 1 C/1 C.
TABLE-US-00031 Electrical properties of lithium batteries Examples Energy density / Wh/Kg Resistance / mΩ Capacity retention rate after 100 cycles of charging and discharging /% Capacity retention rate after 1,000 cycles of charging and discharging /% Comparative Example 4 300.2 3.01 97.1 80.6 Comparative Example 5 300.1 3.04 97.5 - Comparative Example 6 280.4 3.59 95.1 - Comparative Example 7 295.6 3.12 95.6 - Example 38 295.3 2.68 97.2 - Example 39 295.4 2.57 97.9 - Example 40 295.5 2.49 98.6 82.5 Example 41 295.3 2.53 98.5 - Example 42 295.4 2.59 98.2 - Example 43 300.1 2.61 96.9 - Example 44 300.0 2.41 97.5 - Example 45 298.6 2.44 98.3 - Example 46 292.1 2.51 98.4 - Example 47 283.7 3.04 98.1 - Example 48 281.9 3.37 96.9 - Example 49 295.4 2.92 96.8 - Example 50 295.3 2.53 97.8 - Example 51 295.6 2.57 98.1 - Example 52 293.8 2.97 96.4 - Example 53 293.8 2.75 97.8 - Example 54 295.4 2.72 98.0 - Example 55 285.4 2.97 96.9 - Example 56 260.1 2.91 98.4 81.2 Example 57 295.2 2.64 97.7 - Example 58 300.3 2.36 98.6 - Example 59 300.2 2.39 98.5 - Example 60 285.7 2.96 96.7 - Example 61 295.6 2.49 98.4 - Example 62 295.1 2.54 98.2 - Example 63 291.9 2.79 97.4 - Example 64 291.7 2.75 96.8 - Example 65 260.3 2.94 97.6 -
[0277] The present disclosure improves the safety performance of the battery cells by doping and mixing an oxide solid electrolyte into the high nickel ternary positive piece. As shown by the comparison results between Comparative Examples 4-5 and Examples 37-65, the performance of the battery cell was less affected by using the batteries prepared in the present disclosure. The main reasons resided in that the oxide solid electrolyte particles per se had a certain ion conductivity, the introduction of the oxide solid electrolyte within the content range of the solid electrolyte described in the present disclosure did not significantly hinder the ion transport capability of the anode; moreover, the endothermic effect of the oxide solid electrolyte brought down the average temperature of the anode active material during the charging and discharging process, reduced the side reactions of the ternary anode active material under the high temperature, thereby contributing to the long cycle performance of the battery cells. However, too small particle diameter of the doped oxide solid electrolyte, or an excessive amount of the doped oxide solid electrolyte would increase the internal resistance of the battery cells and reduce the energy density of the battery cells.
VI. Piercing Safety Performance Test of the Battery Core
[0278] The lithium batteries prepared in Examples 37-65 and Comparative Examples 4-7 were subjected to piercing safety test of the Lithium-ions battery with reference to the National Standard GB/T31485-2015 of China, namely “Safety requirements and test methods for traction battery of electric vehicles”.
[0279] Piercing test: the battery cell was charged at a constant current of 1C and the constant voltage, the cut-off current was 0.05 C; a high temperature resistant steel needle with a diameter φ 5 mm was penetrated at a speed of 25±5 mm/s along a direction perpendicular to the pole piece of battery; the penetration position was preferably adjacent to a geometrical center of the pierced surface, the steel needle was retained in the battery cell; the pierced battery cell was observed for 30 min, a change in the surface temperature of the battery cell was monitored during the process, and it was recorded whether the battery cell suffered from an outbreak of a fire and an explosion, the results were shown in Table 32.
TABLE-US-00032 Piercing test result record of battery cores Piercing test Voltage before the test /V Voltage after the test /V Surface temperature of battery core /°C Whether the battery cause fire and explosion Passing rate of batteries Comparative Example 4 4.181 0 793.7 Fire and explosion 0/5 Comparative Example 5 4.183 0 710.3 Fire and explosion 0/5 Comparative Example 6 4.189 3.897 57.8 No fire and explosion 5/5 Comparative Example 7 4.19 0 589.2 Fire and explosion 0/5 Example 38 4.183 3.879 53.9 No fire and explosion 5/5 Example 39 4.186 3.982 52.6 No fire and explosion 5/5 Example 40 4.191 4.105 50.9 No fire and explosion 5/5 Example 41 4.193 4.089 47.4 No fire and explosion 5/5 Example 42 4.183 3.955 51.1 No fire and explosion 5/5 Example 43 4.188 0 591.3 Fire and explosion 0/5 Example 44 4.184 3.896 54.2 No fire and explosion 5/5 Example 45 4.188 3.971 42.7 No fire and explosion 5/5 Example 46 4.183 4.078 41.3 No fire and explosion 5/5 Example 47 4.185 3.953 53.1 No fire and explosion 5/5 Example 48 4.183 3.971 50.6 No fire and explosion 5/5 Example 49 4.187 0 601.4 Fire and explosion 0/5 Example 50 4.191 3.876 47.4 No fire and explosion 5/5 Example 51 4.188 3.862 52.8 No fire and explosion 5/5 Example 52 4.187 0 596.9 Fire and explosion 0/5 Example 53 4.186 3.261 55.7 No fire and explosion 5/5 Example 54 4.184 3.967 57.3 No fire and explosion 5/5 Example 55 4.189 3.758 55.3 No fire and explosion 5/5 Example 56 4.191 3.794 57.6 No fire and explosion 5/5 Example 57 4.185 3.612 56.5 No fire and explosion 5/5 Example 58 4.192 4.012 45.8 No fire and explosion 5/5 Example 59 4.193 4.009 46.9 No fire and explosion 5/5 Example 60 4.184 3.768 56.2 No fire and explosion 5/5 Example 61 4.191 4.005 49.4 No fire and explosion 5/5 Example 62 4.193 4.019 48.5 No fire and explosion 5/5 Example 63 4.185 3.971 56.7 No fire and explosion 5/5 Example 64 4.184 3.363 55.4 No fire and explosion 5/5 Example 65 4.190 3.785 56.7 No fire and explosion 5/5
[0280] The present disclosure improved the safety performance of the battery cells by doping and mixing the oxide solid electrolyte into the high nickel ternary positive piece. It was indicated by the comparison results of Comparative Examples 4-5 and Examples 38-42, 44-48, 50-51 and 53-65, the battery cells prepared in the present disclosure did not cause fire and explosion during the piercing process, the surface temperature of the battery core during the piercing process was within a range of 41.3-57.6° C., such that the safety performance of battery cells was improved; in contrast, the positive piece of Comparative Examples 4-5 did not add an oxide solid electrolyte, the battery cells prepared therefrom would catch fire and explode as well as thermal runaway during the piercing process, the maximum surface temperature of the battery cells may reach 793.7° C. The main reasons of the improvement resided in that the oxide solid electrolyte was added into the ternary anode active material, effectively blocking the contact between the ternary active particles, thereby improving the thermal stability of the materials; secondly, the oxide solid electrolyte of the present disclosure per se had a certain thermal capacity, and can absorb a portion of the heat generated by the anode, thereby mitigating overheating of anode.
[0281] As shown in Comparative Examples 6-7 and Examples 38-42, although the oxide solid electrolyte was added in the Comparative Examples 6-7, the particle diameter of the oxide solid electrolytes was too small to block ion transport, thereby increasing interface resistance and reducing energy density of the battery cells; when the particle diameter of the oxide solid electrolytes was too large, its effect of blocking contact between the anode particles was not obvious, resulting in insignificant improvement of safety performance, thus the produced battery cells failed to pass the piercing test. As can be seen, too small or too large particle diameter of the particles doped and mixed into the anode cannot produce the effects of improving safety performance while ensuring energy density of the battery cells.
[0282] It was demonstrated in Examples 40 and 43-48, although the positive piece of Example 43 was added with the oxide solid electrolyte, the doped and mixed amount of the oxide solid electrolyte was too small, the endothermic and heat insulation effects of the oxide solid electrolyte were not obvious, the safety performance of the battery cells was not significantly improved, the battery cells failed to pass the piercing test; the positive piece in Example 48 was added with the oxide solid electrolyte, although the battery cell passed the piercing test, the doped and mixed amount was excessive, which would decrease the energy density of the battery. As can be seen, too small or too large amount of the oxide solid electrolyte doped and mixed into the anode cannot produce the effects of improving safety performance while ensuring energy density of the battery cells.
[0283] Although the oxide solid electrolyte was added in Example 49, its particle diameter D50 was within a preferred range of 0.1-3 .Math.m, and the added amount was within a preferred range of 0.1-10%, the ratio of D50 of the ternary anode material to D50 of the oxide solid electrolyte was less than 5, namely the particle diameters of the ternary anode material and the oxide solid electrolyte were relatively close, resulting in that the amount of the oxide solid electrolyte was insufficient to block contact between the particles of the ternary anode active material when the D50 and the added amount were within the aforementioned ranges, thus the safety performance was poor, the battery cell failed to pass the piercing test, but it resulted in the lower surface temperature of the battery core than the Comparative Examples 4-5, it demonstrated that the oxide solid electrolyte can mitigate the energy during thermal runaway process to some extent.
[0284] Although the oxide solid electrolyte was added in Example 52, its particle diameter D50 was within a preferred range of 0.1-3 .Math.m, and the added amount was within a preferred range of 0.1-10%, the ratio of D50 of the ternary anode material to D50 of the oxide solid electrolyte was larger than 5, but the pre-mixing rotation speed was too small, the dispersion effect was poor, the particles were prone to agglomerate, resulting in poor safety performance, thus the battery cell failed to pass the piercing test; however, it caused the lower surface temperature of the battery core than the Comparative Examples 4-5, it demonstrated that the oxide solid electrolyte can mitigate the energy during thermal runaway process to some extent.
[0285] Examples 40, 55-57, 60-65 indicated that doping different oxide solid electrolytes can enhance safety performance of the battery cell at some extent, wherein the safety performance improvement from LATP was optimum; Examples 40, 61-62, and Examples 53, 64, and Examples 54, 63, and Examples 56, 65 demonstrated that for each electrolyte, the electrolyte composition had little effect on the safety performance of battery cells, each of the battery cells can successfully pass the piercing test.
[0286] Examples 60-65 showed that the positive pieces provided by the present disclosure in combination with the conventional and commercially available electrolytes can produce the effect of improving safety of the battery cores, such that the battery cores can pass the piercing test smoothly.
VII. 180° C. Hot Box Safety Performance Test of Battery Cores
[0287] The battery cell was charged at a constant current of 1 C and the constant voltage, the cut-off current was 0.05 C; and subjected to heating at 180° C. for 2 h; the temperature rise rate was 5° C. /min, the temperature was raised to 180° C. and preserved for 2 h, and observed for 1h; the battery was denoted as passing the test if there was “no fire, no explosion”, otherwise the test result was failed; in addition, the change in the surface temperature of the battery cell during the process was monitored, the results were shown in Table 33.
TABLE-US-00033 Results record of 180° C. hot box safety performance test of battery cores No. Result Voltage before the test /V Voltage after the test /V Weight loss rate of battery % Maximum temperature of the battery surface /°C Comparative Example 4 Failed 4.180 0 / 560.8 Comparative Example 5 Failed 4.182 0 / 549.7 Comparative Example 6 Failed 4.188 0 / 299.6 Comparative Example 7 Failed 4.189 0 / 306.9 Example 38 Passing 4.182 3.883 25.3 188.6 Example 39 Passing 4.185 3.986 16.1 186.4 Example 40 Passing 4.190 4.109 15.2 185.1 Example 41 Passing 4.192 4.093 25.3 185.3 Example 42 Passing 4.182 3.959 26.1 188.1 Example 43 Failed 4.187 0 / 311.5 Example 44 Passing 4.183 3.900 23.9 188.7 Example 45 Passing 4.187 3.975 16.5 185.4 Example 46 Passing 4.182 4.082 17.9 186.3 Example 47 Passing 4.184 3.957 19.1 187.9 Example 48 Passing 4.182 3.987 / 187.9 Example 49 Failed 4.186 0 / 315.4 Example 50 Passing 4.190 3.880 27.1 188.3 Example 51 Passing 4.187 3.866 21.2 187.4 Example 52 Failed 4.186 0 / 328.6 Example 53 Passing 4.185 3.264 21.9 188.5 Example 54 Passing 4.183 3.971 23.8 185.7 Example 55 Passing 4.188 3.762 22.8 187.4 Example 56 Passing 4.190 3.798 21.1 186.6 Example 57 Passing 4.184 3.616 24.1 185.1 Example 58 Passing 4.191 4.009 14.8 181.4 Example 59 Passing 4.192 4.012 15.1 182.8 Example 60 Passing 4.185 3.778 20.9 185.3 Example 61 Passing 4.190 3.995 15.9 183.1 Example 62 Passing 4.192 3.998 16.1 183.3 Example 63 Passing 4.186 3.969 17.5 184.2 Example 64 Passing 4.185 3.669 17.8 184.5 Example 65 Passing 4.189 3.729 18.1 185.1
[0288] The present disclosure improved the safety performance of the battery cells by doping and mixing the oxide solid electrolyte in the high nickel ternary positive piece. Comparative Examples 4-5 and Examples 38-42, 44-47, 50-51 and 53-65 showed that the surface temperature of batter core was within a range of 181.4-188.7° C. when the battery cells prepared by the present disclosure were subjected to the 180° C. hot box test, the weight loss ratio of the battery cells was within a range of 15.1%-27.1%, none of the battery cells suffered from fire and explosion. In contrast, the oxide solid electrolyte was not added into the positive piece of Comparative Examples 4-5, the battery cells prepared therefrom suffered from thermal runaway, the maximum surface temperature of the battery cells reached 560.8° C. The main reasons resided in that the oxide solid electrolyte was added into the ternary anode active material, it effectively blocked contact between the ternary active particles. Secondly, the oxide solid electrolyte of the present disclosure itself had a certain thermal capacity, can absorb a portion of the heat generated by the anode and alleviates the anode overheating. Thus the battery cells can successfully pass the 180° C. hot box test.
[0289] It was apparently indicated from Comparative Examples 6-7 and Examples 38-42, although the oxide solid electrolyte was added in Comparative Examples 6-7, the particle diameter of the oxide solid electrolytes was too small to block ion transport, the interface resistance was increased, and the energy density of the battery cells was decreased; if the particle diameter of the oxide solid electrolytes was too large, its effect of blocking contact between the anode particles was not obvious, the safety performance was not significantly improved, thus the battery cells failed to pass the 180° C. hot box test. As can be seen, too small or too large particle diameter of the particles doped and mixed into the anode cannot produce the effects of improving safety performance while ensuring energy density of the battery cells.
[0290] It can be seen from Examples 40 and 43-48 that although the oxide solid electrolyte was added into the positive piece of Example 43, the effect of improving safety performance cannot be favorably achieved if the amount of the oxide solid electrolyte doped into the positive piece was too small or too large; when the doped amount of the oxide solid electrolyte was too small, the endothermic and heat insulation effects of the solid electrolyte were not obvious, the safety performance was not significantly improved; the oxide solid electrolyte was added into the positive piece in Example 48, although the battery cell obtained therefrom passed the 180° C. hot box test, the doped amount was excessively high, it would reduce the energy density of the battery cell.
[0291] Although the oxide solid electrolyte was added in Example 49, its particle diameter D50 was within a preferred range of 0.1-3 .Math.m, and the added amount was within a preferred range of 0.1-10%, the ratio of D50 of the ternary anode material to D50 of the oxide solid electrolyte was less than 5, namely the particle diameters of the ternary anode material and the oxide solid electrolyte were relatively close, resulting in that the amount of the oxide solid electrolyte was insufficient to block contact between the particles of the ternary anode active material when the particle diameter and the added amount were within the aforementioned ranges, thus the safety performance was poor, the battery cell failed to pass the 180° C. hot box test; but it resulted in the lower surface temperature of the battery core than the Comparative Examples 4-5, it demonstrated that the oxide solid electrolyte can mitigate the energy during thermal runaway process to some extent.
[0292] Although the oxide solid electrolyte was added in Example 52, its particle diameter D50 was within a preferred range of 0.1-3 .Math.m, and the added amount was within a preferred range of 0.1-10%, the ratio of D50 of the ternary anode material to D50 of the oxide solid electrolyte was larger than 5, but the pre-mixing rotation speed was too small, the dispersion effect was poor, the particles were prone to agglomerate, resulting in poor safety performance, thus the battery cell failed to pass the 180° C. hot box test; however, the surface temperature of the battery core was lower than the Comparative Examples 4-5, it demonstrated that the oxide solid electrolyte can alleviate the energy during thermal runaway process to some extent.
[0293] In the Examples provided by the present disclosure, the nickel content x of the ternary anode material LiNi.sub.xCo.sub.yM.sub.1-x-yO.sub.2 was 0.80, 0.83 or 0.88, the higher was the nickel content of the high nickel ternary anode material, the worse was its thermal stability. As can be seen from Examples 54-55, under a circumstance that the positive piece provided by the present disclosure had a high nickel content (x=0.88), the corresponding battery core still can smoothly pass the hot box test; for the anode active material with a low nickel content (x=0.6-0.8), the positive piece provided in the present disclosure can also ensure desirable safety performance.
[0294] Examples 40, 55-57, 60-65 demonstrated that doping with different oxide solid electrolytes can improve the safety performance of the battery cells to a certain extent, wherein the improvement effect of safety performance from the LATP was the best; Examples 40, 61-62, and Examples 53, 64, and Examples 54, 63, and Examples 56, 65 showed that for each electrolyte, the electrolyte composition has little effect on the battery safety performance.
[0295] Examples 60-65 indicated that the positive pieces provided by the present disclosure in combination with the conventional and commercially available electrolytes can produce the effect of improving safety of the battery cores, such that the battery cores can pass the hot box test smoothly.
[0296] The foregoing content merely sets forth the preferred embodiments of the present disclosure, it shall be indicated that the ordinary skilled person in the art can make some improvements and modifications without departing from the inventive concept of the present disclosure, the improvements and modifications shall be deemed to be within the protection scopes of the present disclosure.