HYBRID SOLID STATE ELECTROLYTE

The present disclosure concerns a solid state electrolyte for providing an ion conductive connection between a negative and positive electrode in a battery, the solid state electrolyte comprising: an ion conductive matrix comprising a polymer, and a metal salt dispersed in the ion conductive matrix, and a first ceramic material, wherein at least one of the faces of the ion conductive matrix for connecting to the negative or positive electrode, is infiltrated with the first ceramic material to form a first, hybrid interface layer.