Solid secondary battery and method of preparing the same

Abstract

A solid secondary battery and a method of preparing the same are provided. The solid secondary battery includes a cathode layer, an anode layer, and a solid electrolyte layer between the cathode layer and the anode layer, wherein the cathode layer includes a cathode current collector and a cathode active material layer on at least one side of the cathode current collector. The cathode active material layer includes a composite cathode active material, the composite cathode active material includes a composite of M2S, an alkali metal salt, and a two-dimensional carbonaceous structure, wherein M is an alkali metal, the alkali metal being Li or Na, the two-dimensional carbonaceous structure includes graphene, graphene oxide, reduced graphene oxide, or a combination thereof, and the composite includes a solid solution of the M2S and the alkali metal salt.

Dependencies are inferred from the claim text.