Quaternary cathode material co-modified by wet doping and carbon coating and its preparation method

Abstract

A quaternary cathode material co-modified by wet doping and carbon coating and a preparation method thereof, the chemical formula of the quaternary cathode material is LiNi a co b mn c Al d Ce e Mo f o 2 @C, its preparation method includes the following steps: (1) NiSO 4 ·6H 2 O. CoSO 4 ·7H 2 O, MnSO 4 ·H 2 O and Al 2 (SO 4 ) 3 Add deionized water to obtain a mixed solution; (2) add Ce salt solution, Mo salt solution, complexing agent ammonia solution and precipitant NaOH solution to the mixed solution to react to obtain a precursor slurry; then solidify liquid separation to obtain a quaternary positive electrode material precursor; (3) mixing the quaternary positive electrode material precursor with a lithium salt and calcining to obtain a quaternary positive electrode material; (4) combining the quaternary positive electrode material with a carbon source Mix well, and then calcined, Serve. The quaternary cathode material of the invention has a simple preparation method, and the lithium ion battery assembled using the quaternary cathode material has high discharge capacity and good cycle stability.

Description

technical field [0001] The invention relates to a lithium ion battery positive electrode material and a preparation method thereof, in particular to a quaternary positive electrode material co-modified by wet doping and carbon coating and a preparation method thereof. Background technique [0002] With people's increasing attention to the environment and resources, lithium-ion batteries are widely used in electric vehicles as a new type of power source to reduce greenhouse gas emissions. Ternary cathode material LiNi 1-x-y co x mn y o 2 (NCM) is one of the commonly used lithium-ion cathode materials. However, lithium-ion batteries assembled with cathodes made of it have disadvantages such as low specific energy density and poor rate performance, which lead to weak battery life and short driving distance of electric vehicles, which limits the The further expansion of its market size. [0003] Quaternary cathode material LiNi a co b mn c al d o 2 (NCMA) is a new type...

AI Technical Summary

Problems solved by technology

Ternary cathode material LiNi 1-x-y co x mn y o 2 (NCM) is one of the commonly used lithium-ion cathode materials. However, lithium-ion batteries assembled with cathodes made of it have disadvantages such as low specific energy density and poor rate performance, which lead to weak battery life and short driving distance of electric vehicles, which limits the Further expansion of its market size

Bulk phase doping mainly reduces the occurrence of cracks by stabilizing the crystal structure of the material and improves the electrochemical performance of the positive electrode material, but it hardly protects the surface of the electrode material.

Surface interface engineering is mainly aimed at the unstable surface and interface properties of the positive electrode material, coating other substances on the surface of the positive electrode material, reducing the contact between the positive electrode material itself and the electrolyte, effectively preventing the erosion of HF, and improving the charge transfer at the positive electrode / electrolyte interface. The structure of the positive electrode material does not play a stabilizing role

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