Thin film cadmium chalcogenide/aqueous polysulfide photoelectrochemical solar cells with in-situ tin storage

A photoelectrical system is presented which converts solar energy to both electrical and electrochemically stored energy. A decrease in cell illumination initiates spontaneous reconversion of electrochemical to electrical energy, providing nearly constant (light insensitive) electrical power for an external applied load. The cell contains a thin film CD(Se,Te) photoelectrode and a thin film CoS counterelectrode immersed in an aqueous polysulfide electrolyte separated by cation selective membrane from a tin electrode immersed in an aqueous sulfide electrolyte (Sn/S/sup =/). Cyclic voltammetry indicates that unlike tin/alkali systems, the Sn/S/sup =/ half-cell does not undergo passivation at storage potentials.