Long‐Term Testing of SOFC Stacks at Forschungszentrum Jülich

Abstract Forschungszentrum Jülich is performing long‐term SOFC stack tests for more than 17 years. Within the European project Real‐SOFC (2004–2008) durability tests operating at 700 °C were started with two short stacks which reached the first milestone of 10,000 h in November 2008. The operation of one stack, clearly showing progressive degradation over the last 5,000 h, was terminated after more than 2 years for inspection of the status of the components and interfaces. The second stack is now in operation for more than 5 years having reached 43,800 h in August 2012. The average voltage degradation over the full duration was about 1% per 1,000 h. Another short stack with plasma sprayed protective coatings on the air side of the interconnects is running for more than 14,000 h, showing about 0.12% voltage degradation per 1,000 h. A stack with a similar configuration but LSM cathodes, operated at a temperature of 800 °C, broke down after 2 years. As reason for the break‐down manganese diffusion from the LSM cathode into the 8YSZ electrolyte could be determined by post‐test analysis. All these short stacks have been tested with humidified hydrogen at a fuel utilization of 40% and with dry air. In the meantime a 2.6 kW stack was operated on internally reformed methane for 4,500 h showing about 0.3% voltage degradation per 1,000 h.