In3+-doped Sr2Fe1.5Mo0.5O6−δ cathode with improved performance for an intermediate-temperature solid oxide fuel cell

Promoting the oxygen reduction reaction (ORR) is critical for commercialization of intermediate-temperature solid oxide fuel cells (IT-SOFCs), where Sr2Fe1.5Mo0.5O6−δ (SFM) is a promising cathode by working as a mixed ionic and electronic conductor. In this work, doping of In3+ greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr2Fe1.5Mo0.5−xInxO6−δ (SFMInx), and thus effectively promotes the ORR performance. As a typical example, SFMIn0.1 reduces the polarization resistance (Rp) from 0.089 to 0.046 Q·cm2 at 800 °C, which is superior to those doped with other metal elements. In addition, SFMIn0.1 increases the peak power density from 0.92 to 1.47 W·cm−2 at 800 °C with humidified H2 as the fuel, indicating that In3+ doping at the Mo site can effectively improve the performance of SOFC cathode material.