THERMALLY RESPONSIVE SOLID STATE COMPOSITE ELECTROLYTE SEPARATOR

Provided herein are compositions of solid-state ionically conductive composite materials that include particles of an inorganic phase in a matrix of an organic phase having a positive thermal coefficient of expansion. When the temperature of the composition is below a cutoff temperature T, the composition is ionically conductive and may be used as an electrolyte. As the temperature increases above T, the organic phase expands and reduces the ionic conductivity of the composition.