Investigation of A-site deficient Ba0.9Co0.7Fe0.2Nb0.1O3−δ cathode for proton conducting electrolyte based solid oxide fuel cells

Abstract A novel cathode material for proton conducting electrolyte based solid oxide fuel cells (SOFCs) of A-site deficient Ba 0.9 Co 0.7 Fe 0.2 Nb 0.1 O 3− δ (BCFN) has been synthesized and characterized. The A-site deficient BCFN has demonstrated a thermal expansion coefficient (TEC) similar to that of BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY) electrolyte, enhanced oxygen reduction activity and chemical stability. The application of BCFN in proton-conducting electrolyte-based SOFCs has been investigated, and the SOFCs with Ni-BZCY|BZCY|BCFN configuration demonstrate maximum cell power outputs of 180, 240 and 300 mW cm −2 at 600, 650 and 700 °C, respectively. The cell polarization resistance is as low as 0.951, 0.387 and 0.201 Ω cm 2 under open circuit voltage (OCV) at 600, 650 and 700 °C, respectively. The cell maximum power density increases from 300 to 356 mW cm −2 at 700 °C after over 118 h operating under a constant current of 300 mA cm −2 .