Composite positive electrode material of lithium ion battery and preparation method for composite positive electrode material

Abstract

The invention discloses a composite positive electrode material of a lithium ion battery and a preparation method for the composite positive electrode material, belongs to a chemical power supply material and a preparation method therefor, solves the problem that the existing lithium-rich manganese-based material cladding layer has no electrochemical activity, and by providing a new approach for preparing the cladding layer, solves the problem of degradation of specific capacity and initial coulombic efficiency caused by the side reaction of the lithium-rich manganese-based material. The composite positive electrode material disclosed by the invention consists of the lithium-rich manganese-based material and an FeF<3> cladding layer which coats the exterior of the lithium-rich manganese-based material; the preparation method comprises the following steps of adding CTAB into n-hexanol, heating and stirring, and dividing into three parts averagely; adding Fe(NO<3>)<3>, an NH<4>F water solution and a lithium-rich manganese-based material water phase turbid liquid separately, and mixing the obtained three parts of solutions, standing and reserving and taking a lower water layer and solid, performing centrifuging, separating and ethyl alcohol washing, and solid purifying; and finally performing vacuum drying. The composite material provided by the invention has relatively high initial coulombic efficiency and specific capacity; and by providing an effective approach of material cladding, the FeF<3> nanometer layer can be uniformly dispersed on the surface of the lithium-rich manganese-based material to obtain the uniform cladding layer.

Description

technical field [0001] The invention belongs to a lithium ion battery electrode material and a preparation method thereof, in particular to a lithium ion battery composite cathode material and a preparation method thereof. Background technique [0002] The lithium-rich manganese-based system material has the general formula xLi 2 MnO 3 ·(1-x)LiMO 2 or Li[Li x m 1-x ]O 2 (M=Ni, Co, Mn, Fe, Al, etc., 0<x<1) layered compounds and their doped derivatives are currently the most advantageous lithium-ion battery cathodes in terms of specific capacity, cost, and environmental protection. material, is considered to be the most promising cathode material for the next generation of high specific energy lithium-ion batteries. Lithium-rich manganese-based materials can achieve high first-week discharge specific capacity (>250mAh / g), but their first-week coulombic efficiency is low. The first-week Coulombic efficiency is an important parameter in the practical application ...

AI Technical Summary

Problems solved by technology

[0004] The invention provides a lithium-ion battery composite positive electrode material, and at the same time provides its preparation method, which solves the problem that the existing lithium-rich manganese-based material coating layer does not have electrochemical activity, and provides a new way to prepare the coating layer, thereby overcoming the problem of rich manganese-based materials. Lithium-manganese-based layered cathode materials have the problem of reduced specific capacity and first-week Coulombic efficiency due to electrolyte interface reactions and irreversible activation reactions

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