Preparation and evaluation of novel Bi1.91Sr2Co1.96O7.08 cathode for intermediate temperature-solid oxide fuel cells

Abstract Novel cathode material Bi 1.91 Sr 2 Co 1.96 O 7.08 (BSCO) was synthesized by ethylene glycol assisted sol-gel method for intermediate temperature solid oxide fuel cells (IT-SOFCs). In addition to its good thermal stability, it shows chemical and thermal compatibility with Ce 0.9 Gd 0.1 O 2− γ electrolyte. Thermal expansion coefficient of BSCO is found to be approximately 11.2 × 10 −6 K −1 from 100 °C to 800 °C, which is the main merit of this material compared with other cobaltite based perovskite cathodes. Electrical conductivity of BSCO is about 8–9 S cm −1 between 600 and 700 °C, and polarization resistance of BSCO cathode on Ce 0.9 Gd 0.1 O 2− γ electrolyte are 0.1, 0.3 and 1.3 Ω·cm 2 at 800, 748 and 695 °C, respectively. Maximum power density based on BSCO/GDC/NiO-GDC cell is 495 mW·cm −2 at 700 o C. Given that the thermal compatibility with the electrolyte and the encouraging electrochemical performance, BSCO could be considered as an alternative cathode material for IT-SOFCs.