Fuel cell or electrolyzer and process for its production

The stack has cell elements each having a gas space (9), electrolyte layer (3), cathode (4), anode (5). The cells are separated by sealing layers (24), each of which is of a two part form. This has an isolator plate (14a) of electrolytic material, e.g. zirconium dioxide and a sealing layer of glass ceramic solder.