Multi-layer thin film electrolytes for application in High Temperature Ceramic Electrochemical Devices

Kurzfassung

Reducing thickness of the electrolyte is a key route to reduce ohmic losses in high temperature electrochemical devices and unlock operation at lower temperature. However the production of such a film through conventional ceramic process often requires a sintering step at high temperature – typically above 1200°C – not necessarily compatible with the shrinking behavior and the chemical properties of the supporting materials. This particularly holds true for metal supported cells when pre-manufactured substrates are used. Here we report about a multi-layer electrolyte architecture and its low temperature manufacturing route specifically design for metal supported cells. This consists in interlayers of porous yttria stabilized zirconia (YSZ) directly coated onto the functional electrode and fired at mild temperature – typically below 900°C – followed by a gas tight YSZ and Gadolinium doped Ceria (GDC) double layer deposited by electron beam physical vapor Deposition (EB-PVD). The architecture was implemented into metal supported cells with a size up to 90 mm x 100 mm. Cells were tested in Fuel Cell or Electrolysis operation for more than 1500 hours and 2000 hours respectively. The evolution of the interfaces was monitored by Electrochemical Impedance Spectroscopy, and the microstructure of the thin films was investigated by Scanning Electron Microscopy and Transmission Electron Microscopy. Most Actual status of development will be given and prospects and challenges will be discussed.