Solide Oxide Cells - Development Status at Forschungszentrum Jülich

The development of solid oxide fuel cells (SOFCs) at Forschungszentrum Jülich that started mid of the1990’s achieved since then a very well advanced status.In fact, anode supported cells with thin film 8YSZ electrolyte and LSC cathode reached current density of approx. 3.5A/cm² at 700 °C. The high-chromium containing interconnect steel Crofer 22 APU and its enhanced creep strengthmodification Crofer 22 H are well established in the community. Glass-ceramic sealing based stack design andoperation strategies have been improved resulting in increased mechanical robustness.Recently a 2 kW stack was operated for 5000 h revealing a degradation rate of only 0.3%/kh. Short stacks arecurrently running for more than 64,000 h with degradation rates of 0.7%/kh and for > 34,500 h with el system based on four 5 kW stacks has also been operated successfully.Recently also the use of the “classical” SOFC as electrolyser (SOEC) has been introduced showing moderatedegradation rates.A third approach is the realization of the SOFC/SOEC system as a rechargeable oxide battery (ROB). In such an ROBthe fuel side is filled with a water vapour/hydrogen gas mixture and subsequently sealed off. A metal (in initial studiesiron was used) which can be reduced (charged) in SOEC mode and oxidized (discharged) in fuel cell mode isintegrated in the steam/hydrogen compartment