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.