Evaluation of Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3− δ as a potential cathode for an anode-supported proton-conducting solid-oxide fuel cell

Abstract

The potential application of Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3− δ (BSCF) as a cathode for a proton-conducting solid-oxide fuel cell based on BaCe 0.9Y 0.1O 2.95 (BCY) electrolyte was investigated. Cation diffusion from BCY to BSCF with the formation of a perovskite-type Ba 2+-enriched BSCF and a Ba 2+-deficient BCY at a firing temperature as low as 900 °C was observed, the higher the firing temperature the larger deviation of the A to B ratio from unit for the perovskites. Symmetric cell tests demonstrated the impurity phases did not induce a significant change of the cathodic polarization resistance, however, the ohmic resistance of the cell increased obviously. Anode-supported cells with the electrolyte thickness of ∼50 μm were successfully fabricated via a dual-dry pressing process for the single-cell test. Under optimized conditions, a maximum peak power density of ∼550 and 100 mW cm −2 was achieved at 700 and 400 °C, respectively, for the cell with the BSCF cathode layer fired from 950 °C. At 500 °C, the ohmic resistance is still the main source of cell resistance. A further reduction in membrane thickness would envisage an increase in power density significantly.