High performance Ba0.95Ca0.05Fe0.9-xSnxY0.1O3-δ-SDC as cobalt-free cathode for intermediate-temperature proton-conducting solid oxide fuel cells with BaZr0.1Ce0.7Y0.2O3-δ electrolyte

A novel cobalt-free cathode Ba0.95Ca0.05Fe0.9-xSnxY0.1O3-delta-SDC (x < 0.1), with various ratios of Sn was proposed. Here, it is applied for proton-conducting solid oxide fuel cells (H-SOFCs), for the first time. Special attention is paid to the exploration of doping amount of Sn effect on the phase structure, electronic conductivity, thermal expansion coefficient (TEC) and electrochemical properties. Ca, Sn and Y codoped BaFeO3-delta is expected to stabilize a single perovskite lattice structure down to room temperature. TEC data shows that doping of Sn can effectively decrease thermal expansion coefficient, the average thermal expansion coefficient decreases from 17.8 x 10(-6) K-1 for Ba0.95Ca0.05Fe0.9Y0.1O3-delta to 12 x 10(-6) K-1 for Ba0.95Ca0.05Fe0.85Sn0.05Y0.1O3-delta at the temperature range of room temperature to 850 degrees C. The single-cell with Ba0.95Ca0.05Fe0.85Sn0.05Y0.1O3-delta-SDC cathode achieves the maximum power density of 949 mW cm(-2) at 700 degrees C. These results demonstrate that Ba0.95Ca0.05Fe0.85Sn0.05Y0.1O3-delta-SDC are promising cathodes for proton-conducting solid oxide fuel cells. (C) 2019 Elsevier B.V. All rights reserved.