Effects of operating conditions on performance degradation and anode microstructure evolution of anode-supported solid oxide fuel cells

Performance degradation of the solid oxide fuel cell (SOFC) shortens the cell life in practical applications. Revealing the degradation mechanism is crucial for continuous improvement in cell durability. In this work, the effects of cell operating conditions on the terminal voltage and anode microstructure of the Ni-YSZ (yttria-stabilized zirconia) anode-supported single cell are investigated. The microstructure of the anode active area near the electrolyte is characterized by laser optical microscope and focused ion beam-scanning electron microscopy. Ni depletion at the anode/electrolyte interface region is observed after the 100 h discharge tests. In addition, the long-term stability of the single cell is evaluated at 700°C for 3000 h. After the initial decline, the anode-supported single cell exhibits a good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh. The main performance loss of the cells comes from the initial degradation.