Optimization of metal-supported solid oxide fuel cells with a focus on mass transport

Performance of symmetric-architecture metal-supported solid oxide fuel cells was improved significantly by optimizing the catalyst infiltration process and metal support structure. Optimization of component structure and processing parameters was performed during tape-casting and fabrication of button cells. Mass transport of oxygen in the metal support was identified as a major limitation. To overcome this limitation, pore former loading and thickness of the metal support (130-250 mu m) were optimized. The catalyst infiltration process was also improved by studying the impact of firing temperature (400 degrees C-900 degrees C) and infiltration cycle numbers (1-15). The maximum power density of the optimized cell was 0.9 W cm-2 at 700 degrees C using hydrogen as a fuel, a three-fold increase over the baseline cell performance. The degradation rate of optimized cells at 550 degrees C, 600 degrees C, and 700 degrees C was 2%, 4.5%, and 5.5% per 100 h, respectively. The phenomena of mass transport, catalyst coarsening, and chromium poisoning on the catalyst were analyzed by electrochemical impedance spectroscopy and scanning electron microscopy.