Novel SrSc0.2Co0.8O3−δ as a cathode material for low temperature solid-oxide fuel cell

The SrSc0.2Co0.8O3−δ (SSC) perovskite was investigated as a cathode material for low temperature solid-oxide fuel cell. The material showed an almost linear thermal expansion from room temperature to 1000 °C in air with the average thermal expansion coefficient of only 16.9 × 10−6 K−1. The Sc-doping made the absence of Co4+ in SSC, which resulted in not only dramatically reduced thermal expansion coefficient but also extremely high oxygen vacancies concentrations in the lattice at low temperature. The area specific polarization resistance was 0.206 Ω cm2 for SSC at 550 °C, which is about 52% lower than the value of a Ba0.5Sr0.5Co0.8Fe0.2O3−δ-based cathode. A peak power density as high as 564 mW cm−2 was obtained at 500 °C based on a 20 μm thick Sm0.2Ce0.8O1.9 electrolyte by adopting SSC cathode.