Multi-layered layer arrangement for a solid electrolyte

A cathode-electrolyte-anode unit for an electrochemical functional device, the unit comprising:

• a porous anode and a porous cathode;
• a multi-layered solid electrolyte arranged between said porous anode and said porous cathode;
• said solid electrolyte having characteristics of being formed of a layered structure of at least one first layer and at least one second layer;
• said at least one second layer having a higher oxygen content than said at least one first layer, and said at least one first layer and said at least one second layer having the same composition except for oxygen;
• said at least one first layer being a metallic PVD layer formed of a deposited mixture of metals converted beforehand, by way of a sputtering process, into gas phase;
• and
• said at least one second layer being an oxide-ceramic PVD layer formed of the mixture of metals converted beforehand into the gas phase, or a gaseous mixture, with supply of oxygen or of an oxygen-containing gas as reactive gas or by using a sputtering target consisting of the metal oxide.