Synthesis method of lithium manganese phosphate nanosheets

Abstract

The invention relates to a synthesis method of lithium manganese phosphate nanosheets double coated with graphene and pyrolytic carbon and serving as a cathode material of a lithium ion secondary battery. The nanosheets are about 20 nm thick. The synthesis method comprises steps as follows: (1) the lithium manganese phosphate nanosheets are prepared with a solvothermal method; (2) the surfaces of the lithium manganese phosphate nanosheets are coated with glycan for amino-functionalization, and glycan-coated and amino-functionalized lithium manganese phosphate nanosheets are obtained; (3) the surfaces of the amino-functionalized lithium manganese phosphate nanosheets are coated with graphene oxide; (4) reduction and calcination are performed, and the lithium manganese phosphate nanosheets double coated with graphene and pyrolytic carbon are obtained. The lithium manganese phosphate nanosheets prepared with the method combine excellent characteristics of uniform coating of pyrolytic carbon and excellent electrical conductivity of graphene, and the electrochemical performance of the double-carbon composite lithium manganese phosphate is ensured.

Description

Technical field [0001] The invention belongs to the preparation of lithium ion battery positive electrode materials in the field of electrochemistry and new energy materials, and specifically relates to a method for synthesizing lithium ion secondary battery positive electrode material lithium manganese phosphate nanosheets double-coated with graphene and pyrolytic carbon. Background technique [0002] The progress of society and the continuous growth of people's needs make clean and efficient energy more and more people pay attention. Replacing fuel-fueled vehicles with electric vehicles has become the key development direction of all countries. Battery technology is the core of the production of electric vehicles and plays a vital role in the development and growth of the electric vehicle industry. [0003] Cathode materials in lithium-ion batteries are an important factor restricting their development. Lithium iron phosphate is a common cathode material for lithium-ion batteries...

AI Technical Summary

Problems solved by technology

At present, there are still some problems with the commonly used manganese phosphate lithium carbon composite materials: organic precursors (such as sucrose, citric acid, etc.) pyrolytic carbon can coat the layer more uniformly, but due to the low heat treatment temperature, generally between 600 ° C and 700 ° C ℃, far lower than the graphitization temperature (above 2000 ℃), which makes the conductivity of pyrolytic carbon poor; corresponding to it is graphitized carbon materials, such as acetylene black, carbon nanotubes, graphene, etc. , has high conductivity, and is often used as a conductive additive for electrode materials, but this type of conductive carbon material is often not well dispersed. Compared with pyrolytic carbon, their binding force with active materials is weak, and a large number of agglomerations often occur , can not play a good role in improving the conductivity of the material

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