BaZr0.1Co0.4Fe0.4Y0.1O3-SDC composite as quasi-symmetrical electrode for proton conducting solid oxide fuel cells

Abstract

Symmetric solid oxide fuel cells (SSOFCs) with the identical anode and cathode electrocatalysts show promise to reduce material and system cost while increasing the cell lifespan. In this work, BaZr0.1Co0.4Fe0.4Y0.1O3 (BZCFY) oxide perovskite is proposed as a symmetric electrode for SSOFCs based on proton conducting electrolyte, with targets of reducing temperature and high-performance application. Active oxygen ionic conductor and catalyst, SDC, is composited to improve the cell performance and electrode durability. Those materials show good chemical compatibility while BZCFY is decomposed to alloy and mixed oxide composite, which significantly affects electrode activity. SDC-BZCFY composite gives an electrode polarization resistance of 1.35–13.7 Ω cm2 and 0.32–1.59 Ω cm2 for hydrogen oxidation reaction and oxygen reduction reaction on the proton conducting electrolyte, BZCY, at the temperature range of 700–550 °C, respectively. Moreover, it displays an excellent oxygen reduction kinetics with an impressive activation energy of 0.91 eV. The polarization resistances are significantly reduced in the fuel cell condition owning to the electrochemical promotion effect under open-circuit condition. Quasi-SSOFCs with BZCY electrolyte in a thickness of 480 μm and electrode thickness of 25 μm give a peak power density of 114.8 and 74.3 mW cm−2 at 650 and 600 °C, respectively. In addition, SSOFC also displays acceptable durability under constant voltage operational condition for 25 h. This work highlights alternative active electrode material for symmetric solid oxide fuel cells for low temperature operation.