Ionically conducting, redox active additive composite electrolytes are disclosed. The electrolytes include an ionically conductive component and a redox active additive. The ionically conductive component may be an ionically conductive material such as an ionically conductive polymer, ionically conducting glass-ceramic, ionically conductive ceramic, and mixtures thereof. Electrical energy storage devices that employ the ionically conducting, redox active additive composite electrolytes also are disclosed
STATEMENT OF GOVERNMENT INTERESTS
 This invention was made with government support under Advanced Research Projects Agency-Energy Contract No. DE-AR0000070. The government has certain rights in the invention.