Method for preparing positive electrode material of core-shell structure lithium battery by secondary molten salt method

A technology of positive electrode material and core-shell structure, which is applied in the field of secondary molten salt preparation of core-shell structure lithium battery positive electrode material, can solve the problems of poor surface stability, high nickel ternary material capacity and voltage attenuation, etc., to reduce corrosion, Effect of improving long-life cycle performance and alleviating interfacial lattice mismatch

Active Publication Date: 2021-07-27
CHANGSHU INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, high-nickel ternary materials face serious capacity and voltage attenuation problems, which are the key problems that limit their commercialization
Numerous studies have found that the surface stability of high-nickel ternary materials is poor. 2 and H 2 O has a side reaction, (2) has a serious parasitic reaction with the electrolyte

Method used

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  • Method for preparing positive electrode material of core-shell structure lithium battery by secondary molten salt method
  • Method for preparing positive electrode material of core-shell structure lithium battery by secondary molten salt method
  • Method for preparing positive electrode material of core-shell structure lithium battery by secondary molten salt method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1 High nickel ternary single crystal LiNi 0.7 co 0.15 mn 0.15 o 2 preparation of

[0037] 1) Configure NaCl-KCl-Na according to the mass ratio of 30%: 30%: 40% 2 SO 4 For molten salt, fully grind and mix in a dry environment for later use. The high nickel ternary material LiNi 0.7 co 0.15 mn 0.15 o 2The required raw materials are weighed according to the stoichiometric ratio of lithium hydroxide, nickel carbonate, cobalt carbonate, manganese carbonate, ground and mixed to obtain reactant 1. Wherein, the mass ratio of lithium hydroxide is 5% in excess of its stoichiometric ratio. The mass ratio of the molten salt to the target positive electrode material (core-shell structure lithium battery positive electrode material) is 5:1.

[0038] 2) Fully mix the molten salt with reactant 1, grind, and react at high temperature: react at 600°C for 3h, then continue to react at 900°C for 10h. After the reaction, the cooling rate was 60°C / h, and the temperature w...

Embodiment 2

[0040] Example 2 High nickel ternary material LiNi 0.8 co 0.1 mn 0.1 o 2 preparation of

[0041] 1) Configure NaCl-KCl-Na according to the mass ratio of 60%: 20%: 20% 2 SO 4 For molten salt, fully grind and mix in a dry environment for later use. The high nickel ternary material LiNi 0.8 co 0.1 mn 0.1 o 2 The required raw materials lithium hydroxide, nickel carbonate, cobalt carbonate and manganese carbonate are weighed according to the stoichiometric ratio, ground and mixed for later use. Lithium hydroxide mass is in excess of 5% than its stoichiometric required amount. The mass ratio of molten salt to target cathode material is 1.1:1

[0042] 2) Fully mix the molten salt and the reactants, grind them, and react at high temperature. React at 600°C for 3h, then continue to react at 700°C for 10h. After the reaction, the cooling rate was 20°C / h, and the temperature was lowered to 500°C, followed by furnace cooling to obtain a reaction product, which was a mixture. ...

Embodiment 3

[0044] Example 3 High nickel ternary material LiNi 0.8 co 0.1 mn 0.1 o 2 preparation of

[0045] 1) Configure NaCl-KCl-Na according to the mass ratio of 40%: 20%: 40% 2 SO 4 For molten salt, fully grind and mix in a dry environment for later use. The high nickel ternary material LiNi 0.8 co 0.1 mn 0.1 o 2 The required raw materials lithium hydroxide, nickel carbonate, cobalt carbonate and manganese carbonate are weighed according to the stoichiometric ratio, ground and mixed for later use. Lithium hydroxide mass is in excess of 5% than its stoichiometric required amount. The mass ratio of the molten salt to the target cathode material is 2.0:1.

[0046] 2) Fully mix the molten salt and the reactants, grind them, and react at high temperature. React at 800°C for 3h, then continue to react at 750°C for 10h. After the reaction, the cooling rate was 50°C / h. After cooling down to 500°C, the reaction product was obtained by cooling in the furnace. The reaction product w...

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Abstract

The invention discloses a high-nickel ternary single crystal, and the chemical formula of the high-nickel ternary single crystal is LiNi x co y mn z o 2 , the invention also discloses a core-shell structure lithium battery cathode material and a preparation method thereof. In the material disclosed by the invention, the core part increases the nickel content (high-nickel ternary material) to increase the battery capacity, and the shell part (low-nickel ternary material) increases the manganese content to improve the structural stability of the material. The core and shell have a similar lattice structure, which can also alleviate the lattice mismatch phenomenon at the interface between the two. The surface coating layer can improve the interface stability of the high-nickel ternary single crystal, reduce the erosion of the electrolyte, and finally effectively reduce the parasitic reaction on the surface of the high-nickel ternary single crystal, and improve the long-life cycle performance of the material.

Description

technical field [0001] The invention belongs to the technical field of lithium battery preparation, and in particular relates to a method for preparing a core-shell structure lithium battery cathode material by a secondary molten salt method. Background technique [0002] At present, LiCoO has been successfully commercialized 2 、LiFePO 4 , LiMn 2 o 4 Lithium battery cathode materials still cannot meet the needs of the market. Layered transition metal oxides with higher specific capacity have attracted attention, among which high-nickel ternary materials (no strict definition, LiNi x co y mn z o 2 , x+y+z=1, usually x≥0.5) The specific capacity can reach 200mAh / g, and the energy density of a single battery can reach 300Wh / kg. The urgent need for batteries. However, high-nickel ternary materials face serious capacity and voltage attenuation problems, which are the key problems that limit their commercialization. Numerous studies have found that the surface stability ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G53/00H01M4/36H01M4/505H01M4/525H01M10/0525
CPCY02E60/10
Inventor 杨刚宗意恒
Owner CHANGSHU INSTITUTE OF TECHNOLOGY
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