Performance evaluation of Ca3Co4O9-δ cathode on Sm0.075Nd0.075Ce0.85O2-δ electrolyte for solid oxide fuel cells

Abstract

Ca3Co4O9-δ (Ca349) cathode is prepared by sol-gel method and its performance on new Sm0.075Nd0.075Ce0.85O2-δ (SNDC) electrolyte was evaluated as cathode for intermediate temperature solid oxide fuel cells (IT-SOFC). The crystal structure and chemical compatibility with SNDC electrolyte are studied by X-ray diffraction (XRD). The micromorphology and electrochemical performance of Ca349 with SNDC electrolyte are characterized. The formation of Ca349 phase and good chemical compatibility between Ca349 and SNDC electrolyte are confirmed by XRD. The Ca349 cathode sintered at 850 °C for 5 h shows the best cathode performance, the area specific resistances (ASR) of Ca349 cathode are found to be 0.236 Ω cm2 at 800 °C, and the ASR can be further decreased by incorporating SNDC electrolyte. The composite (Ca349-50 wt% SNDC) gives the lowest ASR values (0.093 Ω cm2 at 800 °C). Its ASR is improved by at least 60% compare to single-phase Ca349 cathode. At 800 °C, the maximal power density of anode-supported SOFCs with Ca349 cathode reaches 410.09 mW cm−2. The total resistance of the cell was only 0.168 Ω cm2. These encouraging data show that Ca349 onto SNDC with good electrochemical performance could be promising as a cathode material of IT-SOFC.