Abstract: The invention relates to solid-state electrolytes for use in lithium-air batteries or in lithium-water batteries. It is the object of the invention to provide solid electrolyte for use in lithium-air batteries or lithium-water batteries, with the solid electrolyte having sufficient strength, good conductivity for lithium ions, imperviousness for gas and water resistance and being inexpensive in manufacture. The solid-state electrolyte in accordance with the invention has an open-pore ceramic carrier substrate. In this respect, at least one layer which is conductive for lithium ions, which has an electrical conductivity of at least 10?5 Scm?1 and which is gas-impervious is formed on the surface facing the cathode. In this respect, the carrier substrate has greater mechanical strength and a larger layer thickness than the at least one layer.