Optimization of electrochemical performance of Ca3Co2O6 cathode on yttria-stabilized zirconia electrolyte for intermediate temperature solid oxide fuel cells

•Ca3Co2O6 (CCO) and YSZ are chemical compatible only up to 800 °C.•A Sm0.2Ce0.8O1.9 buffer layer prevents CCO from directly contacting with YSZ.•The addition of frit can lower the sintering temperature of the cathode to ∼800 °C.•Cathode performance is improved by inhibiting the reaction between CCO with YSZ.

Ca3Co2O6 (CCO) is synthesized by solid state reaction for intermediate temperature solid oxide fuel cells (IT-SOFCs) on yttria-stabilized zirconia (YSZ) electrolyte. Thermal expansion coefficient (TEC), electrical conductivity (σ) and chemical compatibility of CCO with YSZ are characterized. The experiment results show that CCO and YSZ are chemical compatible only up to 800 °C. By introducing a Sm0.2Ce0.8O1.9 (SDC) interlayer to avoid the direct contact of CCO with YSZ, the area specific resistance (ASR) of CCO cathode is significantly decreased from 13.06 Ω cm2 to 0.60 Ω cm2 at 750 °C. Furthermore, the addition of frit can lower the sintering temperature of the cathode to ∼800 °C, also resulting in a remarkable decreasing of the ASR to 3.87 Ω cm2 at 750 °C.