Double-coating-layer positive electrode lithium supplementing material as well as preparation method and application thereof

The invention provides a double-coating-layer positive electrode lithium supplementing material as well as a preparation method and application thereof, belongs to the technical field of lithium ion battery materials, and can solve the problem that the purity and the interface stability of a lithium supplementing material are influenced due to the fact that side reactions are easily generated in an existing carbon coating technology. The double-coating-layer positive electrode lithium supplementing material comprises an inner core containing a lithium-rich material and a double-coating layer coating the surface layer of the inner core containing the lithium-rich material, the double-coating layer comprises a conductive carbon film layer and a poly-sulfur film layer, and the conductive carbon film layer is located between the inner core containing the lithium-rich material and the poly-sulfur film layer. The double-coating-layer positive electrode lithium supplement material can realize physical isolation from