Method for modifying phosphate-coated lithium-rich manganese-based cathode material

Abstract

The invention discloses a method for modifying a phosphate-coated lithium-rich manganese-based cathode material and belongs to the field of lithium ion battery cathode materials. The method comprisescoating steps of: 1) uniformly dispersing a prepared lithium-rich cathode material in a mixed solution of deionized water and an organic solvent to obtain a solution A; 2) dissolving gadolinium nitrate and phosphate in the deionized water to prepare solutions B and C; 3) adding the solutions B and C to the solution A under a room-temperature stirring state, and adjusting the pH value of the solution to 8 to 11 in order that the solutions B and C react and are in-situ deposited onto the surface of the lithium-rich material; 4) stirring and ageing the solution for 2 to 5 hours, performing oil bath evaporation to dryness and performing grinding to obtain a coated precursor; and 5) calcining the coated precursor in an atmosphere at 450 to 600 degrees centigrade for 4 to 6 hours, and naturallycooling the coated precursor to room temperature to finally obtain the GdPO4-coated lithium-rich manganese-based cathode material. The method uses the wet chemical deposition method to in-situ coat the surface of the lithium-rich manganese-based cathode material with the GdPO4, is easy to operate, inhibits the corrosion of the surface of the material by an electrolyte, stabilizes the structure ofthe material, reduces oxygen loss, and has wide application prospects.

Description

technical field [0001] The invention belongs to the field of positive electrode materials of lithium ion batteries, and in particular relates to a modification method of phosphate-coated lithium-rich manganese-based positive electrode materials and its application in lithium ion batteries. Background technique [0002] With the development of the economy and the advancement of science and technology, people have put forward higher requirements on the safety performance, energy and power density, cycle performance, cost and environmental friendliness of batteries. The specific capacity of the existing traditional cathode materials can no longer meet people's increasing demand for high specific energy and high specific power of secondary batteries. With the continuous research and modification of existing positive electrode materials, it is found that in the layered LiMnO 2 During the research process of doping modification, if the content of transition metal elements is cont...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of unstable structure, serious capacity fading and voltage fading of lithium-rich manganese-based positive electrode materials in the cycle process, and proposes a method of coating GdPO on the surface. 4 A method for effectively inhibiting the occurrence of side reactions on the surface of materials and improving structural stability

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