STABILIZED SOLID GARNET ELECTROLYTE AND METHODS THEREOF

An air stable solid garnet composition, comprising: a bulk composition and a surface protonated composition on at least a portion of the bulk composition as defined herein, and the protonated surface composition is present on at least a portion of the exterior surface of the bulk composition at a thickness of from 0.1 to 10,000 nm. Also disclosed is a composite electrolyte structure, and methods of making and using the composition and the composite electrolyte structure.