Method for preparing lithium ion battery anode material with core-shell structure

Abstract

The invention provides a method for preparing a lithium ion battery anode material with a core-shell structure. The method comprises the following steps: dispersing a core shell, namely an anode material, in an aqueous solution of a shell material precursor, adding an organic solvent into the solution, crystallizing and separating the shell material precursor on the surface of the core material, filtering, performing heat treatment, and thus obtaining the lithium ion battery anode material with the core-shell structure. The dissolubility difference of the shell material precursor in an aqueous phase and an organic phase serves as driving force, and the impurity core shell serves as a seed crystal, so that the shell material is uniformly deposited on the surface of the core material, and the lithium ion battery anode material with the core-shell structure is formed. The method has the advantages of uniform coating, simple process, short period, low cost and the like and is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a method for preparing a core-shell structure lithium ion battery cathode material. Background technique [0002] With the miniaturization and thinning of portable electronic devices such as mobile phones, digital cameras, and notebook computers, the market's requirements for the energy density, electrochemical performance, and safety performance of lithium-ion batteries continue to increase. The technical bottleneck of lithium-ion batteries mainly lies in the cathode material. At present, the commonly used cathode materials for lithium-ion batteries are LiCoO 2 、LiNi 0.8 co 0.2 o 2 、LiNi 0.8 co 0.15 Al 0.05 o 2 、LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 , LiMn 2 o 4 、LiFePO 4 Wait. These cathode materials have their own disadvantages: LiCoO 2 The price is high, the structure is unstable after the charging voltage exceeds 4.2V, and the safety becomes poor; LiNi 0.8 co 0.2...

AI Technical Summary

Problems solved by technology

These cathode materials have their own disadvantages: LiCoO 2 The price is high, the structure is unstable after the charging voltage exceeds 4.2V, and the safety becomes poor; LiNi 0.8 co 0.2 o 2 The cycle performance of LiNi is not good, the water absorption is strong, and the storage performance is poor; LiNi 0.8 co 0.15 Al 0.05 o 2 Easy to absorb water, poor storage performance; LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 The structure of LiMn is unstable, and the high temperature storage performance is not good; LiMn 2 o 4 The capacity is low and the high temperature performance is poor; LiFePO 4 The conductivity is low, the rate performance is poor, and the low temperature performance is not good

However, the preparation methods used all have certain defects

For example, the product obtained by dry blending or impregnation method is mainly a mixture of core material and shell material, and no real core-shell structure material is prepared; the precipitation method has many steps, long cycle, difficult to control metering ratio, and large equipment investment; sol - The raw material price of the gel method is high, the processing cycle is long, and the industrialization is difficult

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