Electrochemical comparison of cobalt-free La0.5Sr0.5Fe0.9Mo0.1O3−δ based cathode materials for intermediate-temperature solid oxide fuel cells

A cobalt-free La0.5Sr0.5Fe0.9Mo0.1O3−δ (LSFMo) powders were synthesized by a modified Pechini method and examined as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on proton-conducting electrolyte of BaZr0.1Ce0.7Y0.2O3−δ (BZCY). The button cells of Ni-BZCY/BZCY/LSFMo (LSFMo-BZCY) were fabricated and tested from 600 to 700 °C with humidified H2 (~3% H2O) as a fuel and ambient oxygen as an oxidant. The single cells with LSFMo cathode show the maximum power density of 332 mW cm−2 and the electrode polarization resistance of 0.59 Ω cm2 at 700 °C. While the cells with LSFMo-BZCY composite cathode show much higher maximum power density of 403 mW cm−2 and much lower polarization resistance of 0.23 Ω cm2 at 700 °C. The dramatic improvement of electrochemical performance is attributed to expand TPB reaction zone beyond the interface, a composite cathode consisting of a proton conductor and a mixed oxygen-ion and electron conductor could lead to a very lower polarization resistance and a higher power density.