MANGANESE-BASED SOLID SOLUTION POSITIVE-ELECTRODE MATERIAL, METHOD OF PREPARING THE SAME AND APPLICATION THEREOF

Abstract

A manganese-based solid solution positive-electrode material, wherein the manganese-based solid solution positive-electrode material has a layered structure, and a chemical formula of the manganese-based solid solution positive-electrode material is aNa.sub.2Mn.sub.xR.sub.1-xO.sub.3.Math.(1a)LiMn.sub.yM.sub.1-O.sub.2, where 0.05a<1, 0<x1, 0.1y1, and each of the R and the M in the chemical formula independently comprises any one or combination of at least two of: alkali metal elements, alkaline earth metal elements, and transition metal elements.

Claims

1. A manganese-based solid solution positive-electrode material, wherein the manganese-based solid solution positive-electrode material has a layered structure, and a chemical formula of the manganese-based solid solution positive-electrode material is aNa.sub.2Mn.sub.xR.sub.1-xO.sub.3.Math.(1-a)LiMn.sub.M.sub.1-O.sub.2, where 0.05a<1, 0<x1, 0.1y1, and each of the R and the M in the chemical formula independently comprises any one or combination of at least two of: alkali metal elements, alkaline earth metal elements, and transition metal elements.

2. The manganese-based solid solution positive-electrode material according to claim 1, wherein in the chemical formula, 0.05a0.35.

3. The manganese-based solid solution positive-electrode material according to claim 1, wherein the R in the chemical formula comprises any one of combination of at least two of: Co, Fe, Zn, Cu, Na, K, Zr, Mg, Nb, W, Y, Sr, Ca, and Al.

4. The manganese-based solid solution positive-electrode material according to claim 1, wherein the M in the chemical formula comprises any one of combination of at least two of: Ni, Co, Fe, Zn, Cu, Na, K, Zr, Mg, Nb, W, Y, Sr, Ca, and Al.

5. A preparation method for the manganese-based solid solution cathode material according to claim 1, the method comprising: mixing a sodium-manganese-based oxide material and a single-sintered manganese-based material; and sintering mixture of the sodium-manganese-based oxide material and the single-sintered manganese-based material in an oxygen-containing atmosphere to obtain the manganese-based solid solution positive-electrode material; wherein a chemical formula of the sodium-manganese-based oxide material is Na.sub.2Mn.sub.xR.sub.1-xO.sub.3, where 0<x1, and a chemical formula of the single-sintered manganese-based material is LiMn.sub.M.sub.1-O.sub.2, where 0.1y1; each of the R in the chemical formula of the sodium-manganese-based oxide material and the M in the chemical formula of the single-sintered manganese-based material independently comprises alkaline earth metal elements and/or transition metal elements.

6. The preparation method according to claim 5, wherein a temperature of the sintering is 400-1000 C.

7. The preparation method according to claim 5, wherein the temperature of the sintering is 800-950 C.

8. The preparation method according to claim 5, wherein a D50 of the sodium-manganese-based oxide material is 100 nm-5 m.

9. The preparation method according to claim 5, wherein a specific surface area of the sodium-manganese-based oxide material is 10-40 m.sup.2/g.

10. The preparation method according to claim 5, wherein a preparation method for the sodium-manganese-based oxide material comprises: mixing a sodium source and a manganese source; spray-pyrolyzing mixture of the sodium source and the manganese source in an oxygen-containing atmosphere to obtain the sodium-manganese-based oxide material.

11. The preparation method according to claim 10, wherein the mixture for preparing the sodium-manganese-based oxide material further comprise an R source.

12. The preparation method according to claim 10, wherein, a molar concentration of the sodium source is 0.1-2 mol/L; and/or the sodium source comprises any one or combination of at least two of: sodium citrate, sodium oxalate, sodium acetate, sodium carbonate, sodium hydroxide, and sodium oxide.

13. The preparation method according to claim 10, wherein, a molar concentration of the manganese source is 0.1-2 mol/L; and/or the manganese source comprises any one or combination of at least two of: manganese carbonate, manganese acetate, manganese oxalate, and manganese oxide.

14. The preparation method according to claim 10, wherein, a temperature of the spray-pyrolyzing is 400-1000 C.

15. The preparation method according to claim 5, wherein the D50 of the single-sintered manganese-based material is 1-3 m.

16. The preparation method according to claim 5, wherein a preparation method for the single-sintered manganese-based material comprises: mixing a manganese source and a lithium source; and performing a single sintering on mixture of the manganese source and the lithium source in an oxygen-containing atmosphere to obtain the single-sintered manganese-based material.

17. The preparation method according to claim 16, wherein the mixture for preparing the single-sintered manganese-based material further comprises an M source.

18. The preparation method according to claim 16, wherein, a temperature of the single sintering is 400-1000 C.

19. The preparation method according to claim 5, further comprising: (1) mixing a sodium source of a molar concentration of 0.1-2 mol/L and a manganese source of a molar concentration of 0.1-2 mol/L to form mixed raw materials, wherein the mixed raw materials further comprise an R source; and spray-pyrolyzing the mixed raw materials in the oxygen-containing atmosphere at 400-1000 C. to obtain the sodium-manganese-based oxide material having a D50 of 100 nm-5 m and a specific surface area of 10-40 m.sup.2/g; mixing a manganese source and a lithium source to form another mixed raw materials, wherein the another mixed raw materials further comprise a nickel source and an M source; and single sintering the another mixed raw materials in the oxygen-containing atmosphere at 400-1000 C. to to obtain the single-sintered manganese-based material having a D50 of 1-3 m; (2) mixing the sodium-manganese-based oxide material and the single-sintered manganese-based material and sintering mixture of the sodium-manganese-based oxide material and the single-sintered manganese-based material in the oxygen-containing atmosphere at 800-950 C. to obtain the manganese-based solid solution positive-electrode material; wherein the chemical formula of the sodium-manganese-based oxide material is Na.sub.2Mn.sub.xR.sub.1-xO.sub.3, where 0<x1; the chemical formula of the single-sintered manganese-based material is LiMn.sub.M.sub.1-O.sub.2, where 0.1y1; each of the R in the chemical formula of the sodium-manganese-based oxide material and the M in the chemical formula of the single-sintered manganese-based material independently comprises any one or any combination of at least two of: alkali metal elements, alkaline earth metal elements, and transition metal elements.

20. A lithium-ion battery, comprising the manganese-based solid solution positive-electrode material according to claim 1.

Description

DETAILED DESCRIPTIONS

Embodiment 1

[0051] The present embodiment provides a manganese-based solid solution positive-electrode material having a layered structure. A chemical formula of the manganese-based solid solution positive-electrode material is 0.35Na.sub.2MnO.sub.3.Math.0.65LiMnO.sub.2.

[0052] A preparation method for the manganese-based solid solution positive-electrode material is as follows.

[0053] (1) Na.sub.2MnO.sub.3 and LiMnO.sub.2 are prepared separately.

[0054] For preparing Na.sub.2MnO.sub.3, sodium acetate and manganese carbonate in a molar ratio of the chemical formula are mixed and are spray-pyrolyzed in an oxygen-containing atmosphere at 650 C. to obtain Na.sub.2MnO.sub.3 having a D50 of 5 m and a specific surface area of 10 m.sup.2/g.

[0055] For preparing LiMnO.sub.2, manganese oxide and lithium carbonate are mixed with each other in a lithium:manganese molar ratio of 1.05:1 and are sintered in an oxygen-containing atmosphere at 700 C. to obtain LiMnO.sub.2 having a D50 of 3 m.

[0056] (2) Na.sub.2MnO.sub.3 and LiMnO.sub.2 in a molar ratio of 0.35:0.65 are mixed and sintered in an oxygen-containing atmosphere at 800 C. to obtain the manganese-based positive-electrode material

Embodiment 2

[0057] The present embodiment provides a manganese-based solid solution positive-electrode material having a layered structure. A chemical formula of the manganese-based solid solution positive-electrode material is 0.1Na.sub.2MnO.sub.3.Math.0.9LiMnO.sub.2.

[0058] A preparation method for the manganese-based solid solution positive-electrode material is as follows.

[0059] (1) Na.sub.2MnO.sub.3 and LiMnO.sub.2 are prepared separately.

[0060] For preparing Na.sub.2MnO.sub.3, sodium acetate and manganese carbonate in a molar ratio of the chemical formula are mixed and are spray-pyrolyzed in an oxygen-containing atmosphere at 400 C. to obtain Na.sub.2MnO.sub.3 having a D50 of 4 m and a specific surface area of 25 m.sup.2/g.

[0061] For preparing LiMnO.sub.2, manganese carbonate and lithium carbonate are mixed with each other in a lithium:manganese molar ratio of 1.03:1 and are sintered in an oxygen-containing atmosphere at 900 C. to obtain LiMnO.sub.2 having a D50 of 2 m.

[0062] (2) Na.sub.2MnO.sub.3 and LiMnO.sub.2 in a molar ratio of 0.1:0.9 are mixed and sintered in an oxygen-containing atmosphere at 870 C. to obtain the manganese-based positive-electrode material.

Embodiment 3

[0063] The present embodiment provides a manganese-based solid solution positive-electrode material having a layered structure. A chemical formula of the manganese-based solid solution positive-electrode material is 0.25Na.sub.2Mn.sub.0.6Zr.sub.0.4O.sub.3.Math.0.75LiMnO.sub.2.

[0064] A preparation method for the manganese-based solid solution positive-electrode material is as follows.

[0065] (1) Na.sub.2Mn.sub.0.6Zr.sub.0.4O.sub.3 and LiMnO.sub.2 are prepared separately.

[0066] For preparing Na.sub.2Mn.sub.0.6Zr.sub.0.4O.sub.3, sodium acetate, manganese carbonate, and zirconium acetate in a molar ratio of the chemical formula are mixed and are spray-pyrolyzed in an oxygen-containing atmosphere at 800 C. to obtain Na.sub.2Mn.sub.0.6Zr.sub.0.4O.sub.3 having a D50 of 1.5 m and a specific surface area of 30 m.sup.2/g.

[0067] For preparing LiMnO.sub.2, manganese oxide and lithium carbonate are mixed with each other in a lithium:manganese molar ratio of 1.01:1 and are sintered in an oxygen-containing atmosphere at 700 C. to obtain LiMnO.sub.2 having a D50 of 1 m.

[0068] (2) Na.sub.2Mn.sub.0.6Zr.sub.0.4O.sub.3 and LiMnO.sub.2 in a molar ratio of 0.25:0.75 are mixed and sintered in an oxygen-containing atmosphere at 950 C. to obtain the manganese-based positive-electrode material.

Embodiment 4

[0069] Being different from the embodiment 1, a chemical formula of the solid solution in the present embodiment is 0.4Na.sub.2MnO.sub.3.Math.0.6LiMnO.sub.2, and molar ratios in a preparation method therefor may be adjusted accordingly.

[0070] The remaining operations and parameters in the preparation method are the same as those in the embodiment 1.

Embodiment 5

[0071] Being different from the embodiment 1, a chemical formula of the solid solution in the present embodiment is 0.9Na.sub.2MnO.sub.3.Math.0.1LiMnO.sub.2, and molar ratios in a preparation method therefor may be adjusted accordingly.

[0072] The remaining operations and parameters in the preparation method are the same as those in the embodiment 1.

Embodiment 6

[0073] Being different from the embodiment 1, the temperature of the sintering in the operation (2) of the present embodiment is 750 C.

[0074] The remaining operations and parameters in the preparation method are the same as those in the embodiment 1.

Embodiment 7

[0075] Being different from the embodiment 1, the temperature of the sintering in the operation (2) of the present embodiment is 1000 C.

[0076] The remaining operations and parameters in the preparation method are the same as those in the embodiment 1.

Embodiment 8

[0077] Being different from the embodiment 1, the D50 of LiMnO.sub.2 in the operation (1) of the present embodiment is 4 m.

[0078] The remaining operations and parameters in the preparation method are the same as those in the embodiment 1.

Embodiment 9

[0079] The present embodiment provides a manganese-based solid solution positive-electrode material having a layered structure. A chemical formula of the manganese-based solid solution positive-electrode material is 0.1Na.sub.2MnO.sub.3.Math.0.9LiMn.sub.0.5Ni.sub.0.5O.sub.2.

[0080] A preparation method for the manganese-based solid solution positive-electrode material is as follows.

[0081] (1) Na.sub.2MnO.sub.3 and LiMn.sub.0.5Ni.sub.0.5O.sub.2 are prepared separately.

[0082] For preparing Na.sub.2MnO.sub.3, sodium acetate and manganese carbonate are spray-pyrolyzed in an oxygen-containing atmosphere at 650 C. to obtain Na.sub.2MnO.sub.3 having a D50 of 5 m and a specific surface area of 10 m.sup.2/g.

[0083] For preparing LiMn.sub.0.5Ni.sub.0.5O.sub.2, manganese oxide, nickel hydroxide, and lithium carbonate are mixed with each other in a lithium:manganese:nickel molar ratio of 1.05:0.5:0.5 and are sintered in an oxygen-containing atmosphere at 700 C. to obtain LiMn.sub.0.5Ni.sub.0.5O.sub.2 having a D50 of 2.5 m.

[0084] (2) Na.sub.2MnO.sub.3 and LiMn.sub.0.5Ni.sub.0.5O.sub.2 in a molar ratio of 0.1:0.9 are mixed and sintered in an oxygen-containing atmosphere at 800 C. to obtain the manganese-based positive-electrode material.

Control Embodiment 1

[0085] Being different from the embodiment 1, a pure LiMnO.sub.2 positive-electrode material is provided in the present control embodiment, and only the operation (1) for preparing LiMnO.sub.2 in the embodiment 1 is performed.

[0086] The remaining operations and parameters of the preparation method are the same as those in the embodiment 1.

Control Embodiment 2

[0087] The present control embodiment provides a manganese-based positive-electrode material having a LiMnO.sub.2 core coated by aluminum oxide. A preparation method for the positive-electrode material is as follows.

[0088] For preparing LiMnO.sub.2, manganese oxide and lithium carbonate in a lithium:manganese molar ratio of 1.05:1 are mixed and are sintered in an oxygen-containing atmosphere at 700 C. to obtain LiMnO.sub.2 having a D50 of 3 m.

[0089] Subsequently, aluminum oxide of 500 nm is mixed with and coats LiMnO.sub.2 to prepare the aluminum-oxide-coated LiMnO.sub.2 material having the D50 of 3 m.

Control Embodiment 3

[0090] Being different from the embodiment 9, a pure LiMn.sub.0.5Ni.sub.0.5O.sub.2 positive-electrode material is provided in the present control embodiment, and only the operation (1) for preparing LiMn.sub.0.5Ni.sub.0.5O.sub.2 in the embodiment 9 is performed.

[0091] The remaining operations and parameters of the preparation method are the same as those in the embodiment 9.

[0092] The positive-electrode material provided in each of the embodiments 1-9 and control embodiments 1-3 is mixed with conductive carbon black, polyvinylidene fluoride, and N-methylpyrrolidone to form a positive-electrode slurry. The positive-electrode slurry is coated on an aluminum foil. The aluminum foil coated with the positive-electrode slurry is dried and rolled to obtain a positive electrode. The positive electrode having a diameter of 12 mm is placed in a positive electrode shell having an inner diameter of 18 mm. 100 L of electrolyte is injected into the positive electrode shell, and a 16 m separator is arranged. A 14 m lithium sheet is placed on the separator, and a spacer is arranged. Furthermore, a negative electrode shell is capped thereto, so as to form a button battery. Electrochemical performance tests are performed under following conditions:

[0093] (1) Capacity pergram tests are performed at a 0.1 C charging-discharging current in voltage ranges of 2.5V-4.2V, 2.5V-4.35V, 2.5V-4.4V, and 2.5V-4.5V.

[0094] (2) Cycling performance tests are performed at 45 C., a voltage range of 2.5V-4.35V, and a 1 C current for 100 cycles.

[0095] Test results are shown in Table 1.

TABLE-US-00001 TABLE 1 capacity retention Capacity Capacity Capacity Capacity rate after pergram pergram pergram pergram 100 2.5~ 2.5~ 2.5 V~ 2.5~ cycles at 4.2 V 4.35 V 4.4 V 4.5 V 45 C. (mAh/g) (mAh/g) (mAh/g) (mAh/g) (%) Embodiment 130 140 150 170 94 1 Embodiment 150 160 170 180 93 2 Embodiment 143 153 163 173 96 3 Embodiment 110 120 130 140 95 4 Embodiment 30 40 50 60 98 5 Embodiment 120 130 140 150 90 6 Embodiment 100 110 120 130 85 7 Embodiment 120 130 140 150 70 8 Embodiment 160 170 180 190 96 9 Control 100 110 115 120 60 embodiment 1 Control 95 105 110 115 80 embodiment 2 Control 110 115 120 125 65 embodiment 3

[0096] According to the results of the embodiment 1, the embodiment 4 and the embodiment 5, when a value of the a is excessively large (>0.35), i.e., a proportion of a sodium-manganese-based oxide material is excessively high, the capacity is less utilized, and the capacity at high voltages is also lower. However, the cycling performance is improved, proving that a sodium-manganese phase facilitates the cycling performance of the overall material to be improved.

[0097] According to the results of the embodiment 1, the embodiment 6 and the embodiment 7, when the temperature in the operation (2), in which mixing and fusion are performed to form the solid solution, is excessively low, fusion of two phases is affected, the solid solution may not be formed easily, leading to a significant decrease in the capacity pergram. At the same time, the cycling performance is not improved. When the temperature in the operation (2) is excessively high, the pure manganese-based material may be modified, such that the two phases may not be fused easily, the capacity is reduced, and the cycling performance is poor.

[0098] According to the results of the embodiment 1 and the embodiment 8, the D50 of the single-sintered manganese-based material and the D50 of the sodium-manganese-based oxide material need to match with each other. When the D50 of the single-sintered manganese-based material and the D50 of the sodium-manganese-based oxide material do not match with each other, fusion of the two phases is affected, purity of the resulting solid solution material is low, ultimately leading to a decrease in the capacity and leading to reduced cycling performance.

[0099] By comparing the results of the embodiment 1 and the control embodiment 1 and comparing the results of the embodiment 9 and the control embodiment 3, pure manganese-based positive-electrode materials have a low capacity pergram and poor cycling performance. However, after the sodium-manganese-based material is used to form the solid solution, the capacity pergram of the material is improved, and the cycling performance is improved. Therefore, the prepared material is a very promising material. By comparing the results of the embodiment 1 and the control embodiment 2, conventional treatment processes still cannot solve the problems of poor cycling performance at the room temperature and the low capacity pergram of the manganese-based material. However, by forming the solid solution with the sodium-manganese-based material, instead of simple coating or doping, a structure of a bulk phase of the manganese-based material is stabilized, such that the capacity pergram and the cycling performance of the manganese-based positive-electrode material are improved.

[0100] In summary, the present disclosure provides the manganese-based solid solution material having the layered structure. The sodium-manganese-based material is introduced, and the sodium-manganese-based material and the manganese-based substrate material cooperatively form the solid solution. Spinel phases are prevented from being formed in the manganese-based material; stability of the layered structure is improved; and cycling stability, especially at high temperatures, of the positive-electrode material is improved. In addition, the sodium-manganese-based material has high conductivity, conductivity of the positive-electrode material is improved, and the capacity of the positive-electrode material is improved. The button battery is arranged with the manganese-based solid solution positive-electrode material of the present disclosure, the a in the chemical formula is limited to 0.05a0.35, and the temperatures and the D50 of the materials during preparation are controlled. A capacity pergrapm of the button battery may be higher than 170 mAh/g at 0.1 C charging-discharging current, in the voltage range of 2.5-4.5V, and at the room temperature. The capacity pergrapm of the button battery may be higher than 163 mAh/g at 0.1 C charging-discharging current, in the voltage range of 2.5-4.4V, and at the room temperature. The capacity pergrapm of the button battery may be higher than 140 mAh/g at 0.1 C charging-discharging current, in the voltage range of 2.5-4.35V, and at the room temperature. The capacity pergrapm of the button battery may be higher than 130 mAh/g at 0.1 C charging-discharging current, in the voltage range of 2.5-4.2V, and at the room temperature. When the button battery is tested under a condition of a high temperature of 45 C., a 0.1 C/0.1 C current, and 2.5-4.35V, a capacity retention rate of the button battery after 100 cycles is over 93%.