Set forth herein are garnet material compositions, e.g.,
lithium-stuffed garnets and
lithium-stuffed garnets doped with
alumina, which are suitable for use as electrolytes and catholytes in
solid state battery applications. Also set forth herein are
lithium-stuffed garnet thin films having fine grains therein. Disclosed herein are novel and inventive methods of making and using lithium-stuffed garnets as catholytes, electrolytes and / or anolytes for
all solid state lithium rechargeable batteries. Also disclosed herein are novel electrochemical devices which incorporate these garnet catholytes, electrolytes and / or anolytes. Also set forth herein are methods for preparing novel structures, including dense thin (<50 um) free standing membranes of an ionically conducting material for use as a catholyte,
electrolyte, and, or, anolyte, in an electrochemical device, a battery component (positive or negative
electrode materials), or a complete
solid state
electrochemical energy storage device. Also, the methods set forth herein disclose novel
sintering techniques, e.g., for heating and / or field assisted (FAST)
sintering, for
solid state
energy storage devices and the components thereof.