LITHIUM-RICH OXIDE POSITIVE ELECTRODE MATERIAL, PREPARATION METHOD THEREFOR, AND LITHIUM ION BATTERY

Abstract

A lithium-rich oxide positive electrode material. At least one unit lattice parameter (a, b, c) of the material decreases as the temperature increases at a temperature between 50 to 350 degrees. After treatment for 0.5 to 10 hours under the condition of 150 to 350° C., the degree of ordering of the material structure is increased, and the material has a higher discharge specific capacity and a higher discharge voltage when applied to a positive electrode of a lithium ion battery.

Claims

1. A lithium-rich oxide positive electrode material, wherein when the material is subjected to X-ray diffraction analysis at a temperature between 50° C. and 350° C., at least one lattice parameter (a, b, c) decreases as the temperature increases.

2. The lithium-rich oxide positive electrode material according to claim 1, wherein the lithium-rich oxide positive material has a general formula of Li.sub.1+xNi.sub.yCo.sub.2Mn.sub.uM.sub.dO.sub.2, wherein 0<x≤0.2; 0≤y≤0.35; 0≤z≤0.35; 0.5≤u≤0.9; 0≤d≤0.5; and M is one or more selected from nickel, cobalt, manganese, iron, aluminum, vanadium, titanium, zirconium, tin, niobium, molybdenum, ruthenium and the like.

3. The lithium-rich oxide positive electrode material according to claim 1, wherein the lithium-rich oxide has a crystal structure selected from layered structure, spinel structure, molten salt structure and monoclinic layered structure.

4. A method for preparing the lithium-rich oxide positive electrode material according to claim 1, comprising charging the material at electric potential of 4.5-4.8V vs. Li.sup.0, and discharging to 2.0-4.4V to conduct an electrochemical treatment.

5. The method according to claim 4, wherein the current density in the electrochemical treatment is 25-250 mA/g.

6. The method according to claim 4, wherein the lithium-rich oxide positive material has a general formula of Li.sub.1+xNi.sub.yCo.sub.2Mn.sub.uM.sub.dO.sub.2, wherein 0<x≤0.2; 0≤y≤0.35; 0≤z≤0.35; 0.5≤u≤0.9; 0≤d≤0.5; M is one or more selected from nickel, cobalt and manganese, and the crystal structure is layered structure; wherein the method of electrochemical treatment is: charging the lithium-rich oxide positive electrode material with a layered structure at electrical potential of 4.6-4.8V vs. Li.sup.0, and discharging to 2.0-3.2V; the cycle number of the electrochemical treatment is 1-300 times.

7. The method according to claim 4, wherein the lithium-rich oxide positive material has a general formula of Li.sub.1+xNi.sub.yCo.sub.2Mn.sub.uM.sub.dO.sub.2, wherein 0<x≤0.2; 0≤y≤0.35; 0≤z≤0.35; 0.5≤u≤0.9; 0≤d≤0.5; M is one or more selected from iron, aluminum, vanadium, titanium, zirconium, niobium and molybdenum, and the crystal structure is spinel structure or molten salt structure; wherein the method of electrochemical treatment is: charging the lithium-rich oxide positive electrode material with a spinel structure or molten salt structure at electrical potential of 4.6-4.8V vs. Li.sup.0, and discharging to 2.0-3.0V; the cycle number of the electrochemical treatment is 1-300 times.

8. The method according to claim 4, wherein the lithium-rich oxide positive material has a general formula of Li.sub.1+xNi.sub.yCo.sub.2Mn.sub.uM.sub.dO.sub.2, wherein 0<x≤0.2; 0≤y≤0.35; 0≤z≤0.35; 0.5≤u≤0.9; 0≤d≤0.5; M is one or more selected from titanium, zirconium, tin and ruthenium, and the crystal structure is monoclinic layered structure; wherein the method of electrochemical treatment is: charging the lithium-rich oxide positive electrode material with a monoclinic layered structure at electrical potential of 4.6-4.8V vs. Li.sup.0, and discharging to 2.0-4.4V; the cycle number of the electrochemical treatment is 1-300 times.

9. The method according to claim 4, wherein after subjecting the lithium-rich oxide positive electrode material to electrochemical treatment, the method further comprises conducting a thermal treatment; wherein the method of thermal treatment is: conducting the treatment under conditions of 150-350° C. for 0.5-10 h.

10. A lithium-ion battery, comprising a positive electrode, a negative electrode, a membrane and an electrolyte solution, wherein the positive electrode is made of the lithium-rich oxide positive electrode material according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0046] FIG. 1 shows the change of the lattice parameters of the lithium-rich positive electrode material with a layered structure prepared in Example 1 without electrochemical treatment as the temperature changes.

[0047] FIG. 2 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 is charged to 4.8V and discharged to 2.0V once.

[0048] FIG. 3 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 is charged to 4.8V and discharged to 2.0V for 100 times.

[0049] FIG. 4 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 is charged to 4.8V and discharged to 2.0V for 300 times.

[0050] FIG. 5 is the charge-discharge curve figure of the lithium-rich positive electrode material Li.sub.1.14N.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 without thermal treatment or being treated at 200° C. for 2 h after charged to 4.8V and discharged to 2.0V once.

[0051] FIG. 6 is the charge-discharge curve figure of the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 without thermal treatment or being treated at 250° C. for 5 h after charged to 4.8V and discharged to 2.0V once.

[0052] FIG. 7 is the charge-discharge curve figure of the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure prepared in Example 1 without thermal treatment or being treated at 300° C. for 1 h after charged to 4.8V and discharged to 2.0V once.

[0053] FIG. 8 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.2Mn.sub.0.4Ti.sub.0.4O.sub.2 is charged to 4.8V and discharged to 2.0V for the first time.

[0054] FIG. 9 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.2Ru.sub.0.5Ti.sub.0.5O.sub.3 is charged to 4.6V and discharged to 2.0V for the first time.

DETAILED DESCRIPTION

[0055] For further understanding the present disclosure, the lithium-rich oxide positive electrode material, the method for preparing the same and the lithium-ion battery provided in the present disclosure will be illustrated in conjunction with embodiments hereinafter. The scope of protection of the present disclosure is not limited by the following embodiments.

Example 1

[0056] 1) Nickel acetate, cobalt acetate, manganese acetate were mixed at a molar ratio of nickel element, cobalt element and manganese element=1:1:4, and mixed and stirred for 5 h. The precipitation were dried, to give the precursor (Ni.sub.1/6Co.sub.1/6Mn.sub.4/6)CO.sub.3.

[0057] 2) The precursor (Ni.sub.1/6CO.sub.1/6Mn.sub.4/6)CO.sub.3 obtained in Step 1) and lithium carbonate at a molar ratio of 1:0.7 were subjected to thermal treatment at 850° C. for 24 h, cooled to room temperature, and milled to give a lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136CO.sub.0.136Mn.sub.0.544O.sub.2.

[0058] 3) The above lithium-rich positive electrode material with a layered structure was subjected to electrochemical treatment. The specific treatment was: 8 g the above lithium-rich positive electrode with a layered structure, 1 g acetylene black, 1 g polyvinylidene fluoride and 30 g N-methyl pyrrolidone were mixed at normal temperature and normal pressure to form slurry, and the slurry was evenly coated on the aluminum foil to give the pole piece. The obtained pole piece was dried at 80° C. and pressed tightly. The pole piece was cut into 1.32 cm.sup.2 round slices as the positive electrode, and metal lithium slice was used as the negative electrode. 1 mol/L LiPF.sub.6 ethylene carbonate (EC) and dimethyl carbonate (DMC) solution was used as the electrolyte solution, wherein the volume ratio of EC and DMC was 1:1. In a glove box full of argon, a button cell was assembled. The obtained half-cell was subjected to a cycle performance test with an electrochemical tester. The test temperature was 25° C., the charge cut-off voltage was 4.8V vs. Li.sup.+/Li.sup.0, and the discharge cut-off voltage was 2.0V vs. Li.sup.+/Li.sup.0. 1-300 cycles were carried out.

[0059] 4) The lithium-rich positive electrode material with a layered structure was subjected to X-ray diffraction analysis at different temperatures using an X-ray diffractometer of German Bruker Corporation or a synchrotron light source. The test conditions were: light source: Cu-Kα ray, Cu target, tube pressure: 40V, tube current: 40 mA, scanning speed: 2°/min, 2θ scan range: 15-90°, step length: 0.02°, divergence slit (DS): 1 mm, anti-scatter slit (SS): 8 mm, graphite monochromator; or synchrotron radiation source, and the temperature range of test: 20° C.-400° C.

[0060] FIG. 1 shows the change of the lattice parameters of the lithium-rich positive electrode material with a layered structure without electrochemical treatment as the temperature changes. It can be obviously concluded from the figure that the lattice parameters a=b, and c linearly increase as the temperature increases. This is due to the thermal expansion effect of material, and is in line with the results of the report about LiNi.sub.0.5Mn.sub.0.5O.sub.2 layered material in Yang Shao-Horn et al., Chemistry of Materials, 20, 4936-4951 (2008).

[0061] FIG. 2 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure is charged to 4.8V and discharged to 2.0V once. It can be concluded from the figure that at a temperature between room temperature and 100° C., all of the lattice parameters a=b, and c increase as the temperature increases. This is due to the thermal expansion effect of material, and the result is similar to the change of the original material. As the temperature continuously increases, at a temperature between 100° C. and 350° C., the lattice parameters a=b decrease as the temperature increases at 100-250° C. The lattice parameter c decreases as the temperature increases at 100-190° C. and 300-350° C.

[0062] FIG. 3 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure is charged to 4.8V and discharged to 2.0V for 100 times. It can be concluded from the figure that at a temperature between room temperature and 100° C., all of the lattice parameters a=b, and c increase as the temperature increases. This is due to the thermal expansion effect of material, and the result is similar to the change of the original material. As the temperature continuously increases, at a temperature between 100° C. and 350° C., the lattice parameters a=b decrease as the temperature increases at 100-280° C. The lattice parameter c decreases as the temperature increases at 100-250° C.

[0063] FIG. 4 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure is charged to 4.8V and discharged to 2.0V for 300 times. It can be concluded from the figure that at a temperature between room temperature and 100° C., all of the lattice parameters a=b, and c increase as the temperature increases. This is due to the thermal expansion effect of material, and the result is similar to the change of the original material. As the temperature continuously increases, at a temperature between 100° C. and 350° C., the lattice parameters a=b decrease as the temperature increases at 100-300° C. The lattice parameter c decreases as the temperature increases at 100-300° C.

[0064] 5) The obtained half-cell was subjected to cycle performance test using an electrochemical tester. The test temperature was 25° C., the charge cut-off voltage was 4.8V vs. Li.sup.+/Li.sup.0, and the discharge cut-off voltage was 2.0V vs. Li.sup.+/Li.sup.0. After 1 cycle, the cell was taken apart in a glove box full of argon, treated at 200-300° C. for 1-5 h, and then assembled into a cell according to the method in above Step 3), and then the electrochemical performance test was conducted.

[0065] FIG. 5: After a thermal treatment at 200° C. for 2 h, the above material was subjected to electrochemical test according to the method in Step 5). Compared with the electrode material without thermal treatment, the material after treatment has higher voltage (3.65V vs. 3.57V) and discharge specific capacity (255 mAh/g vs. 250 mAh/g), thereby indicating that the material after treatment has lower defect density.

[0066] FIG. 6: After a thermal treatment at 250° C. for 5 h, the above material was subjected to electrochemical test according to the method in Step 5). Compared with the electrode material without thermal treatment, the material after treatment has higher voltage (3.68V vs. 3.57V) and discharge specific capacity (256 mAh/g vs. 250 mAh/g), thereby indicating that the material after treatment has lower defect density.

[0067] FIG. 7: After a thermal treatment at 300° C. for 1 h, the above material was subjected to electrochemical test according to the method in Step 5). Compared with the electrode material without thermal treatment, the material after treatment has higher voltage (3.62V vs. 3.57V) and discharge specific capacity (256 mAh/g vs. 250 mAh/g), thereby indicating that the material after treatment has lower defect density.

Examples 2-15

[0068] The lithium-rich positive electrode material Li.sub.1.14Ni.sub.0.136Co.sub.0.136Mn.sub.0.544O.sub.2 with a layered structure of Example 1 was prepared according to the method of Example 1 with the other test conditions remaining unchanged expect only the technological parameters of the electrochemical treatment and/or thermal treatment. The specific technological parameters and the results were shown in Table 1.

TABLE-US-00001 TABLE 1 Preparation technological parameters and performance test results of the lithium-rich positive electrode material with a layered structure Electrochemical performance Temperature interval Discharge specific capacity/ in which lattice Voltage/(voltage of the (discharge specific capacity of Electrochemical treatment parameters a, b material after thermal the material after thermal charge discharge Number Thermal treatment and c decrease as treatment vs. voltage of treatment vs. discharge specific cut-off cut-off of Temperature/ Time/ the temperature the material without capacity of the material without Example voltage/V voltage/V cycles ° C. h increases/° C. thermal treatment) thermal treatment) 2 4.6 2.0 1 — — 100-250 — — 3 4.6 2.0 100 — — 100-290 — — 4 4.6 2.0 300 — — 100-315 — — 5 4.6 2.0 1 200 2 — 3.65 V vs. 3.57 V 254 mAh/g vs. 250 mAh/g 6 4.6 2.0 100 200 2 — 3.55 V vs. 3.21 V 250 mAh/g vs. 235 mAh/g 7 4.6 2.0 300 200 2 — 3.52 V vs. 3.1 V 244 mAh/g vs. 230 mAh/g 8 4.6 2.0 1 250 5 — 3.66 V vs. 3.57 V 256 mAh/g vs. 250 mAh/g 9 4.6 2.0 100 250 5 — 3.59 V vs. 3.21 V 252 mAh/g vs. 235 mAh/g 10 4.6 2.0 300 250 5 — 3.55 V vs. 3.1 V 246 mAh/g vs. 230 mAh/g 11 4.6 2.0 1 300 1 — 3.66 V vs. 3.57 V 256 mAh/g vs. 250 mAh/g 12 4.6 2.0 100 300 1 — 3.61 V vs. 3.21 V 255 mAh/g vs. 235 mAh/g 13 4.6 2.0 300 300 1 — 3.58 V vs. 3.1 V 249 mAh/g vs. 230 mAh/g 14 4.8 3.2 1 — — 100-325 — — 15 4.8 3.2 1 300 1 — 3.60 V vs. 3.55 V 250 mAh/g vs. 245 mAh/g

[0069] In Table 1, taking the data of Example 5 as an example, the voltage was “3.65V vs. 3.57V”, wherein 3.65V was the voltage of the material prepared by the method of Example 5 in Table 1; and 3.57V was the voltage of a material with only electrochemical treatment and without thermal treatment based on the preparation method of Example 5. The discharge specific capacity was “254 mAh/g vs. 250 mAh/g”, wherein 254 mAh/g was the discharge specific capacity of the material prepared by the method of Example 5 in Table 1; and 250 mAh/g was the discharge specific capacity of a material with only electrochemical treatment and without thermal treatment based on the method of Example 5. Other examples and Table 2 and Table 3 are in the same way.

Example 16

[0070] 1) Manganese (III) oxide, titanium dioxide and lithium carbonate were mixed at a molar ratio of lithium element, titanium element and manganese element=3:1:1, ball-milled with a high energy ball-milling at the speed of 400 r/min for 10 h, to give the precursor. The precursor was thermally treated at a temperature of 900° C. in gas atmosphere of Ar gas or N.sub.2 gas for 24 h, cooled to room temperature, and milled to give lithium-rich positive electrode material Li.sub.1.2Mn.sub.0.4Ti.sub.0.4O.sub.2.

[0071] 2) The above lithium-rich positive electrode material with a spinel or rock salt structure was subjected to electrochemical treatment. The specific treatment was: 8 g the above lithium-rich positive electrode with a spinel or rock salt structure, 1 g acetylene black, 1 g polyvinylidene fluoride and 30 g N-methyl pyrrolidone were mixed at normal temperature and normal pressure to form slurry, and the slurry was evenly coated on the aluminum foil to give the pole piece. The obtained pole piece was dried at 80° C. and pressed tightly. The pole piece was cut into 1.32 cm.sup.2 round slices as the positive electrode, and metal lithium slice was used as the negative electrode. 1 mol/L LiPF.sub.6 ethylene carbonate (EC) and dimethyl carbonate (DMC) solution was used as the electrolyte solution, wherenin the volume ratio of EC and DMC was 1:1. In a glove box full of argon, a button cell was assembled. The obtained half-cell was subjected to cycle performance test with an electrochemical tester. The test temperature was 25° C., the charge cut-off voltage was 4.8V vs. Li.sup.+/Li.sup.0, and the discharge cut-off voltage was 2.0V vs. Li.sup.+/Li.sup.0. 1-100 cycles were carried out.

[0072] 3) The lithium-rich positive electrode material with a spinel or rock salt structure was subjected to X-ray diffraction analysis at different temperatures using an X-ray diffractometer of German Bruker Corporation or a synchrotron light source. The test conditions were: light source: Cu-Kα ray, Cu target, tube pressure: 40V, tube current: 40 mA, scanning speed: 2°/min, 2θ scan range: 15-90°, step length: 0.02°, divergence slit (DS): 1 mm, anti-scatter slit (SS): 8 mm, and graphite monochromator; or synchrotron radiation source, and the temperature range of test: 20° C.-400° C.

[0073] FIG. 8 shows the change of the lattice parameters of the electrode material as the temperature changes after the lithium-rich positive electrode material Li.sub.1.2Mn.sub.0.4Ti.sub.0.4O.sub.2 with a spinel/rock salt structure is charged to 4.8V and discharged to 2.0V once. It can be concluded from the figure that at a temperature between room temperature and 100° C., all the lattice parameters a=b=c increase as the temperature increases. This is due to the thermal expansion effect of material, and the result is similar to the change of the original material. As the temperature continuously increases, in the temperature interval of 50° C. to 350° C., the lattice parameters a=b=c decrease as the temperature increases at 70-270° C.

Examples 17-22

[0074] The lithium-rich positive electrode material Li.sub.1.2Mn.sub.0.4Ti.sub.0.4O.sub.2 prepared with a spinel/rock salt structure of Example 16 was prepared according to the method of Example 16 with the other test conditions remaining changed except only the technological parameters of electrochemical treatment and/or thermal treatment. The specific technological parameters and the results were shown in Table 2.

TABLE-US-00002 TABLE 2 Preparation technological parameters and electrochemical performance of the lithium-rich positive electrode material with a spinel/rock salt structure Electrochemical performance Temperature interval Discharge specific capacity/ in which lattice Voltage/(voltage of the (discharge specific capacity of Electrochemical treatment parameters a, b material after thermal the material after thermal Charge Discharge Number Thermal treatments and c decrease as treatment vs. voltage of treatment vs. discharge specific cut-off cut-off of Temperature/ Time/ the temperature the material without capacity of the material without Example voltage/V voltage/V cycles ° C. h increases/° C. thermal treatment) thermal treatment) 17 4.8 2.0 1 — — 100-270 — — 18 4.8 2.0 100 — — 100-300 — — 19 4.8 2.0 300 — — 100-330 — — 20 4.8 2.0 1 300 1 — 3.50 V vs. 3.40 V 258 mAh/g vs. 250 mAh/g 21 4.8 2.0 100 300 1 — 3.48 V vs. 3.15 V 256 mAh/g vs. 235 mAh/g 22 4.8 2.0 300 300 1 — 3.58 V vs. 2.9 V 245 mAh/g vs. 230 mAh/g

Example 23

[0075] 1) Ruthenium oxide, titanium oxide and lithium carbonate were mixed at a molar ratio of lithium element, ruthenium element and titanium element=4:1:1, milled with a high energy ball-milling at a speed of 600 r/min for 10 h, to give a precursor. The precursor was thermally treated at a temperature of 1050° C. and in an air atmosphere for 24 h, cooled to room temperature and milled to give a lithium-rich positive electrode material Li.sub.2Ru.sub.0.5Ti.sub.0.5O.sub.3.

[0076] 2) The above lithium-rich positive electrode material with a monoclinic layered structure was subjected to electrochemical treatment. The specific treatment was: 8 g the above lithium-rich positive electrode with a monoclinic layered structure, 1 g acetylene black, 1 g polyvinylidene fluoride and 30 g N-methyl pyrrolidone were mixed at normal temperature and normal pressure to form slurry, and the slurry was evenly coated on the aluminum foil to give the pole piece. The obtained pole piece was dried at 80° C. and pressed tightly. The pole piece was cut into 1.32 cm.sup.2 round slices as the positive electrode, and metal lithium slice was used as the negative electrode. 1 mol/L LiPF.sub.6 ethylene carbonate (EC) and dimethyl carbonate (DMC) solution was used as the electrolyte solution, wherein the volume ratio of EC and DMC was 1:1. In a glove box full of argon, a button cell was assembled. The obtained half-cell was subjected to cycle performance test with an electrochemical tester. The test temperature was 25° C., the charge cut-off voltage was 4.8V vs. Li.sup.+/Li.sup.0, and the discharge cut-off voltage was 2.0V vs. Li.sup.+/Li.sup.0. 1-100 cycles were carried out.

[0077] 3) The lithium-rich positive electrode material with a monoclinic layered structure was subjected to X-ray diffraction analysis at different temperatures using an X-ray diffractometer of German Bruker Corporation or a synchrotron light source. The test conditions were: light source: Cu-Kα ray, Cu target, tube pressure: 40V, tube current: 40 mA, scanning speed: 2°/min, 2θ scan range: 15-90°, step length: 0.02°, divergence slit (DS): 1 mm, anti-scatter slit (SS): 8 mm, and graphite monochromator; or synchrotron radiation source, and the temperature range of test: 20° C.-400° C.

[0078] FIG. 9 shows the change of the lattice parameters as the temperature changes after the lithium-rich positive electrode material Li.sub.2Ru.sub.0.5Ti.sub.0.5O.sub.3 with a monoclinic layered structure is charged to 4.6V and discharged to 2.0V once. It can be concluded from the figure that at a temperature between room temperature and 100° C., the lattice parameters a, b and c increase as the temperature increases. This is due to the thermal expansion effect of material, and the result is similar to the change of the original material. As the temperature continuously increases, in the temperature interval of 50° C. to 350° C., the lattice parameter c decreases as the temperature increases at 70-170° C. and 200-240° C.

Examples 24-29

[0079] The lithium-rich positive electrode material Li.sub.2Ru.sub.0.5Ti.sub.0.5O.sub.3 with a monoclinic layered structure prepared in Example 23 was prepared according to the method of Example 23 with the other test conditions remaining unchanged expect only the technological parameters of the electrochemical treatment and/or thermal treatment. The specific technological parameters and the results were shown in Table 3.

TABLE-US-00003 TABLE 3 Preparation technological parameters and performance test results of the lithium-rich positive electrode material with a monoclinic layered structure Electrochemical performance Temperature interval Discharge specific capacity/ in which lattice Voltage/(voltage of the (discharge specific capacity of Electrochemical treatment parameters a, b material after thermal the material after thermal charge discharge Number Thermal treatment and c decrease as treatment vs. voltage of treatment vs. discharge specific cut-off cut-off of Temperature/ Time/ the temperature the material without capacity of the material without Example voltage/V voltage/V cycles ° C. h increases/° C. thermal treatment) thermal treatment) 24 4.6 2.0 1 — — 100-250 — — 25 4.6 2.0 100 — — 100-275 — — 26 4.6 2.0 300 — — 100-300 — — 27 4.6 2.0 1 300 1 — 3.47 V vs. 3.45 V 265 mAh/g vs. 255 mAh/g 28 4.6 2.0 100 300 1 — 3.45 V vs. 3.25 V 260 mAh/g vs. 245 mAh/g 29 4.6 2.0 300 300 1 — 3.42 V vs. 3.0 V 245 mAh/g vs. 230 mAh/g

[0080] The above descriptions are only preferred embodiments of the present disclosure. It should be noted that a number of modifications and refinements may be made by one of ordinary skills in the art without departing from the principles of the disclosure, and such modifications and refinements are also considered to be within the scope of protection of the disclosure.