METHOD FOR MAKING UNIFORM POROUS SURFACE LAYER ON GARNET THIN FILM

A solid garnet composition includes a bulk composition having a lithium garnet; and a surface composition having a protonated garnet on at least a portion of the exterior surface of the lithium garnet, such that the protonated garnet is uniformly disposed over the at least a portion of the exterior surface of the lithium garnet. A method of making a solid garnet composition includes pre-treating an air sensitive lithium-containing garnet with water to form a uniform protonated garnet surface composition; and contacting the uniform protonated garnet surface composition with an acid to form a porous uniform protonated garnet surface composition.