Optimization of electrochemical performance of Ca_3Co_2O_6 cathode on yttria-stabilized zirconia electrolyte for intermediate temperature solid oxide fuel cells

摘要

Ca_3Co_2O_6 (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 (a) and chemical compatibility of CCO with YSZ are characterized. The experiment results show that CCO and YSZ are chemical compatible only up to 800 ℃. By introducing a Sm_(0.2)Ce_(0.8)O_(1.9) (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 cm~2 to 0.60 Ω cm~2 at 750 ℃. Furthermore, the addition of frit can lower the sintering temperature of the cathode to ～800 ℃, also resulting in a remarkable decreasing of the ASR to 3.87 Ω cm~2 at 750 ℃.