Preparation method of spherical lithium iron phosphate cathode material

Abstract

A preparation method of a spherical lithium iron phosphate cathode material. The method comprises steps of: 1) preparing lithium source, divalent ferric salt, phosphor salt compound and doped metallic element in a molar ratio of 0.95-1.05:1:1:0.005-0.05 into a solution; adding the solution, reducing agent and precipitating agent into a reaction kettle with an overflow mouth through a metering pump; preparing a spherical lithium iron phosphate precursor through reaction condition control; 2) cladding a layer of nano metal oxide or metallic carbide with excellent conductivity on a surface of the spherical lithium iron phosphate precursor by using polymer as an adjuvant; 3) placing the spherical lithium iron phosphate cladded with metal oxide or metallic carbide in an atmosphere protection furnace, introducing inert atmosphere, insulating for 6-24 h at 500-900 DEG C, cooling naturally to a room temperature to obtain the spherical lithium iron phosphate cladded with metal oxide or metallic carbide conductive film. The lithium iron phosphate material prepared by the method has advantages of uniform chemical components and easily controlled product morphology. Especially, the cladding of metal oxide or metallic carbide enhances conductivity between lithium iron phosphate particles and tap density of the material.

Description

technical field

[0001] The invention relates to the technical field of cathode materials for lithium ion batteries, in particular to a method for preparing spherical lithium iron phosphate cathode materials through the process of synthesizing spherical lithium iron phosphate precursors by a liquid phase method and coating them with metal oxides or metal carbides. technical background

[0002] Among the many secondary battery systems, lithium-ion batteries have the advantages of high working voltage, high energy density, long cycle life, low self-discharge rate, and environmental protection, and have become the main trend of secondary battery development. Among them, the positive electrode material is an important part of lithium-ion batteries, and the positive electrode materials of commercial lithium-ion batteries include lithium cobalt oxide (LiCoO 2 ), lithium nickelate (LiNiO 2 ), lithium manganese oxide with spinel structure (LiMn 2 o 4 ), lithium iron phosphate (LiF...

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