Preparation method of positive electrode lithium supplement agent with high ionic conductivity

The invention provides a preparation method of a positive electrode lithium supplement agent with high ionic conductivity, which comprises the following steps: S1, uniformly mixing a nano iron oxide and a lithium source at a high speed, sintering the mixture for the first time in an inert atmosphere, and crushing the sintered material to obtain Li5FeO4, S2, putting the lithium source, a phosphorus source, a silicon source, a germanium source and a bromine source into a ball milling tank according to a certain proportion, and carrying out ball milling to obtain the positive electrode lithium supplement agent with high ionic conductivity. Adding zirconium oxide ball-milling beads of different specifications according to a certain proportion, and mixing at a high speed to obtain a solid electrolyte to-be-sintered material; according to the invention, a layer of superconducting solid electrolyte is coated on Li5FeO4 through a solid phase mixing and reinforcing phase sintering method, the synthesis method is simpl