Low thermal expansion material Bi0.5Ba0.5FeO3-δ in application for proton-conducting ceramic fuel cells cathode

The cobalt-free material of Bi3+-doped BaFeO3-delta (BBFO) is synthesized and applied as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with proton conducting electrolyte Ba(Zr0.1Ce0.7Y0.2)O-3 (BZCY). The as-prepared BBFO demonstrates a tetragonal structure with sufficient chemical compatibility, high thermal stability and low thermal expansion coefficient. BBFO exhibits higher electrical conductivity of 4.1 S cm(-1) compared to the parent material BaFeO3-delta (BFO) of 3.5 S cm(-1). The composite cathode BBFO-BZCY with the mass ratio of 7:3 presents a relatively low R-p of 0.128 Omega cm(2) at 700 degrees C in air. According to the oxygen reduction reaction process, the rate-determining step is transformed from charge transfer to oxygen gas (O-2) adsorption-dissociation with the rising temperature. In addition, the performance of the anode-supported cell NiO-BZCY vertical bar BZCY vertical bar BBFO-BZCY is 120 mW cm(-2) as the thickness of electrolyte is 150 mu m. It thus promises BBFO as a novel cathode for proton-conducting ceramic fuel cells. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.