Investigation on the Performance and Durability Behavior for the Anode-Supported Solid Oxide Fuel Cell with Composite Cathodes

The anode-supported solid oxide fuel cell (SOFC) comprises of NiO-8YSZ | 8YSZ | LSM-GDC | LSCF and the performance durability is executed for over 1000 hours. It shows low degradation phenomena under constant current operation during the complete testing period. The cell performance decreases with the decreasing of the temperature, and the maximum power densities are 408, 265, and 163 mW cm-2 at 800, 750, and 700 °C, respectively. According to the EIS analysis with the equivalent circuit model of five serial components, all resistances decrease with the testing time except the non-charge transfer resistance of the cathode. However all resistances increase with the decreasing of the temperature on the contrary. The ohmic resistance of the cell (RO) dominates the cell performance under the whole durability test period as well as the operation temperature. In this study, the RO is determined by the interfacial contact resistances, which occurred between the cell and the connecting components. The LSM-GDC | LSCF interfaces formed the discontinuous gap due to the weak attachment and external loading. The result of the activation energy analysis shows that the rate-determination step of the cell is existed in the anode side between 700 and 800 °C. However, the cell performance is controlled from the domination of the RO at 800 °C shift to the joint contributions of the RO, anodic polarization (RAP), and cathodic polarization (RCP) at 700 °C.