Methods for manufacturing a freestanding solid state ionic conductive membrane

A method for manufacturing a freestanding solid state ionic conductive membrane, the method comprising:

• providing a removable support substrate, wherein the removable support substrate comprises a carbon tape or a carbon paste coated material;
• forming a solid state ionic conductive membrane directly on the carbon tape or carbon paste coated material, wherein the entirety of the solid state ionic conductive membrane is directly on the carbon tape or carbon paste coated material, wherein the solid state ionic conductive membrane comprises a solid state ionic conductive material that selectively allows at least one of Li+, Na+, and K+ to pass through under the presence of an electric field or chemical potential, wherein a solid state ionic conductivity of the solid state ionic conductive material is higher than >10−7 S/cm;
• and
• combusting the at least one of carbon tape and carbon paste coated material to remove the removable support substrate from the solid state ionic conductive membrane, whereby the entirety of the solid state ionic conductive membrane becomes completely detached to provide the freestanding solid state ionic conductive membrane.