Preparation method and application of modified carbon-coated lithium iron phosphate positive electrode material

Abstract

The invention discloses a preparation method and application of a modified carbon-coated lithium iron phosphate positive electrode material, belonging to the technical field of lithium iron phosphate batteries. The lithium iron phosphate positive electrode material is prepared by a secondary sintering method, and before the second sintering, boron / nitrogen co-doped single-walled carbon nanotubes are introduced as an inorganic carbon source. The pore structure of the carbon nanotubes can accelerate the transmission speed of lithium ions and shorten the diffusion path of lithium ions. The single-walled carbon nanotubes modified by boron / nitrogen co-doping can form a new three-dimensional conductive network on the surface of the lithium iron phosphate positive electrode material to improve the electronic conductivity. Nitrogen atoms and boron atoms can also cooperate with each other, and the electrical conductivity of the carbon coating layer is enhanced by changing the charge distribution of the carbon nanotubes and the carbon coating layer. At the same time, polyacrylate-polyacrylamide-polystyrene triblock copolymer is introduced as a dispersant, and the formed three-dimensional barrier can effectively prevent the boron / nitrogen co-doped single-walled carbon nanotubes from agglomerating, thereby further improving the electrochemical performance of the lithium iron phosphate.

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