Performance Degradation Analysis of Different Type SOFCs

Long term durability tests of six different type SOFCs, which have been developed by Mitsubishi Hitachi Power Systems (MHPS), Kyocera, TOTO, NGK SPARK PLUG (NTK), NGK INSULATORS (NGK), and Murata Manufacturing (Murata) have been started under the New Energy and Industrial Technology Development Organization (NEDO) project from FY2013. 2012 model of the Kyocera's stack which was operated until 10,000 hours, showed stability compared with 2008 model. The voltage decay rate was 0.2%/1000hr. The dominant degradation factors of this stack were IR drop and cathode overvoltage. 2012 model of the NTK's stack showed that it has an initial voltage drop up to 1,000 hours and the degradation factors were IR drop and cathode overvoltage. The voltage decay rate was 0.6%/1000hr including thermal cycling. The stacks of MHPS's, TOTO's, NGK's, and Murata's were still in the middle of durability test. In this study, we report our recent activities toward the durability and the dominant performance factors, such as IR drop and overvoltage of anode and cathode, for the six types of SOFCs.