Coated spherical Li-rich cathode material and preparation method thereof

Abstract

A coated spherical Li-rich cathode material comprises a main phase Li-rich cathode material, wherein the main phase Li-rich cathode material is uniformly coated with a coating phase; the general formula of the main phase Li-rich cathode material is xLi2MnO3*(1-x) LiMO2, and x is larger than zero and smaller than one; the coating phase is a carbon layer; the mass ratio of a main phase to the coating phase is 1:(1%-12%); and the average particle diameter of a primary particle of a nanoscale Li-rich cathode material is 20-60 nm, and the average particle diameter of the coated spherical Li-rich cathode material is 1-15 mu m. A preparation method of the coated spherical Li-rich cathode material comprises steps as follows: step one, the primary particle of the nanoscale Li-rich cathode material is prepared with a sol-gel method; and step two, the coated spherical Li-rich cathode material is prepared.

Description

technical field [0001] The invention relates to a lithium-ion battery cathode material and a preparation method thereof, in particular to a coated spherical lithium-rich cathode material and a preparation method thereof. Background technique [0002] In recent years, due to the lithium-rich cathode material xLi 2 MnO 3 ·(1-x)LiMO 2 The advantages of high specific capacity (200–300mAh / g), good cycle performance, wide charge and discharge range, and environmental friendliness have sparked a research boom and become LiCoO 2 One of the most promising alternatives. The methods for synthesizing lithium-rich materials mainly include high-temperature solid-phase method, co-precipitation method, sol-gel method, hydrothermal method, and spray drying method. [0003] The co-precipitation method is the most commonly used method for synthesizing the precursors of ternary cathode materials. This method can achieve atomic-level mixing. However, in practice, different types of cations d...

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Problems solved by technology

[0004] Although lithium-rich cathode materials have excellent electrochemical performance, their shortcomings limit their practical applications: (1) Li 2 MnO 3 The components have poor conductivity, which leads to poor rate performance of the material, especially at high rates; (2) The first charge and discharge process destroys the surface lattice structure of the material, and the compatibility with the electrolyte is poor at high charge voltage, resulting in capacity decay

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