Lithium iron manganese phosphate composite positive electrode material, preparation method and application thereof

Abstract

The application provides a lithium manganese iron phosphate composite positive electrode material, a preparation method and application thereof. The lithium manganese iron phosphate composite positive electrode material comprises a lithium manganese iron phosphate material and an artificial CEI film coated on the surface of the lithium manganese iron phosphate material; the artificial CEI film comprises a functional copolymer matrix, Li3PO4 and a ferrocene derivative branched chain; the functional copolymer matrix has a borate ester bond and an imine bond; the Li3PO4 is loaded in a crosslinking network of the functional copolymer matrix; and the ferrocene derivative branched chain is grafted on a side chain of the functional copolymer matrix. In the lithium manganese iron phosphate composite positive electrode material, the ferrocene is oxidized and reduced during charging and discharging, thereby triggering the rupture and recombination of the borate ester bond and the imine bond in the functional copolymer matrix, promoting the self-repairing of the artificial CEI film, and simultaneously providing an ion migration path by the Li3PO4, so that the battery cycle stability and fast charging performance are significantly improved in cooperation.

Images