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Composite cathode material and preparation method and application thereof, and lithium ion battery

A composite cathode material, lithium-ion battery technology, applied in the direction of positive electrode, battery electrode, secondary battery, etc., can solve the problems of poor battery cycle performance and low lithium replenishment efficiency

Active Publication Date: 2021-01-26
SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the lithium supplementation efficiency of traditional lithium supplement materials is low, and non-conductive inert substances will remain after delithiation, resulting in poor cycle performance of the battery

Method used

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  • Composite cathode material and preparation method and application thereof, and lithium ion battery
  • Composite cathode material and preparation method and application thereof, and lithium ion battery
  • Composite cathode material and preparation method and application thereof, and lithium ion battery

Examples

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preparation example Construction

[0035] A preparation method of a composite positive electrode material is one of the preparation methods of the above composite positive electrode material, and the preparation method of the composite positive electrode material comprises the following steps:

[0036] Step S210: ball milling and mixing the positive electrode material and the metal compound to obtain a coating.

[0037] Wherein, after ball milling, the surface of the positive electrode material is coated with a layer of metal compound to form a metal compound layer, that is, the coating is the positive electrode material whose surface is coated with the metal compound.

[0038] Further, in the step of ball milling and mixing the positive electrode material and the metal compound, the rotational speed of the ball mill is 200 rpm to 600 rpm, and the time of ball milling is 30 min to 50 min. Specifically, a ball mill is used for ball milling. More specifically, the mass ratio of the ball milling beads to the posi...

Embodiment 1

[0053] The preparation steps of the composite cathode material of this embodiment are as follows:

[0054] LiCoO 2 Cathode material and NiF 2 At the same time, it was added to a ball mill and ball milled for 30 minutes at a speed of 200 rpm to obtain NiF 2 Coated LiCoO 2 Cathode material, among them, NiF 2 accounted for LiCoO 2 With a mass fraction of 0.2wt%, the ball-milled beads with LiCoO 2 The mass ratio is 10:1.

[0055] Then, the NiF 2 Coated LiCoO 2 Cathode material added Li 2 o 2 In methanol solution, stirred at a temperature of 80°C and a stirring speed of 400rpm until the solvent was completely evaporated, and the solid was dried at 120°C for 12h to obtain Li 2 o 2 and NiF 2 Double-coated composite cathode materials, in which Li 2 o 2 accounted for LiCoO 2 The mass fraction of is 1wt%.

Embodiment 2

[0057] The preparation steps of the composite cathode material of this embodiment are as follows:

[0058] LiMn 2 o 4 Cathode material and CoF 2 At the same time, it was added to a ball mill and ball milled for 40 minutes at a speed of 400rpm to obtain CoF 2 Coated LiMn 2 o 4 Cathode materials, among which, CoF 2 accounted for LiMn 2 o 4 The mass fraction is 0.1wt%, and the ball-milled beads with LiMn 2 o 4 The mass ratio is 15:1.

[0059] Then, the CoF 2 Coated LiMn 2 o 4 The material is added to Li 2 o 2 In the isopropanol solution, stir at a temperature of 60°C and a stirring speed of 500rpm until the solvent is completely evaporated. After the solid is dried at 120°C for 12h, the obtained Li 2 o 2 and CoF 2 Double-coated composite cathode materials, in which Li 2 o 2 accounted for LiMn 2 o 4 The mass fraction of is 2wt%.

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Abstract

The invention relates to a composite cathode material and a preparation method thereof and a lithium ion battery, and belongs to the technical field of batteries. The composite cathode material comprises a cathode material, a metal compound layer and a lithium peroxide layer, the surface of the cathode material is coated with the metal compound layer, and the surface of the side, away from the cathode material, of the metal compound layer is coated with the lithium peroxide layer. The metal compound layer of the composite cathode material can be used as a catalyst to reduce the decomposition potential of lithium peroxide, and in the first charging process, the metal compound can catalyze efficient decomposition of lithium peroxide and release Li+ for efficient lithium supplementation; andmeanwhile, the metal compound layer is remained on the surface of the cathode material, so that the effect of a physical barrier layer can be achieved, the cathode material is prevented from being directly contacted with the electrolyte, the interface side reaction of the cathode material is reduced, the interface stability of the cathode material and the electrolyte is improved, and the cycle performance of the battery is improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a composite positive electrode material, its preparation method, application and lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, good power performance, and long cycle life, and have been widely used in consumer electronics, electric vehicles, and energy storage. During the first charging process of lithium-ion batteries, a passivation film composed of lithium salts, that is, SEI film, will be formed on the surface of the negative electrode, resulting in the first irreversible capacity loss. In order to improve the first effect and make up for the loss of active lithium caused by the formation of the negative electrode SEI film during the first charge and discharge process, it is necessary to use lithium supplement materials to supplement lithium to the battery. However, the lithium supplementation efficiency...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/525H01M4/505H01M4/58H01M10/0525H01M10/42
CPCH01M4/366H01M4/525H01M4/505H01M4/5825H01M10/0525H01M10/4235H01M2004/028Y02E60/10
Inventor 贺理珀陈巍张耀
Owner SUNWODA ELECTRIC VEHICLE BATTERY CO LTD
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