Fast ion conductor coated lithium iron phosphate positive electrode material as well as preparation method and application thereof

The invention belongs to the technical field of lithium ion battery positive electrode materials, and particularly relates to a fast ion conductor coated lithium iron phosphate positive electrode material as well as a preparation method and application thereof. The positive electrode material comprises a lithium iron phosphate matrix and a coating layer coating the outer surface of the matrix, the molecular formula of the lithium iron phosphate matrix is LiFe1-xMxPO4, x is greater than or equal to 0 and less than or equal to 0.02, and M is at least one of manganese, titanium, magnesium, aluminum, zirconium and rare earth elements; the coating layer sequentially comprises a lithium selenate inner layer and a carbon outer layer from the substrate to the outside. Through in-situ reaction, the selenium carbonate coated inner layer is firstly formed on the surface of the iron phosphate precursor, then the selenium carbonate is coated with the carbon source layer, then the lithium selenate coated inner layer and th