US Patent 8940446 Solid state lithium-air based battery cell

In an example, the present invention provides a solid state battery device, e.g., battery cell or device. The device has a current collector region and a lithium containing anode member overlying the current collector region. The device has a thickness of electrolyte material comprising a first garnet material overlying the lithium containing anode member. The thickness of electrolyte material has a density ranging from about 80 percent to 100 percent and a porous cathode material comprising a second garnet material overlying the thickness of electrolyte material. The porous cathode material has a porosity of greater than about 30 percent and less than about 95 percent and a carbon bearing material overlying a surface region of the porous cathode material. In an example, the carbon bearing material comprises substantially carbon material, although there can be variations.