Electrochemical energy source and electronic device provided with such an electrochemical energy source

Electrochemical energy source, comprising:

• a substrate, and
• at least one stack deposited onto said substrate, the stack comprising:
• an first electrode,
• a second electrode, and
• an intermediate solid-state electrolyte separating the first electrode and the second electrode;
• and
• at least one electron-conductive barrier layer being deposited between the substrate and the stack, which barrier layer is adapted to at least substantially preclude diffusion of active species of the stack into said substrate,
• wherein the energy source further comprises at least one material layer surrounding the stack at least partially, and a stress reducing means positioned between the stack and the surrounding material layer for reducing stress in the surrounding material layer during expansion and contraction of the stack.