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

The SrSc0.2Co0.8O3-delta (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 degrees C in air with the average thermal expansion coefficient of only 16.9 x 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 Omega cm(2) for SSC at 550 degrees C, which is about 52% lower than the value of a Ba0.5Sr0.5Co0.8Fe0.2O3-delta-based cathode. A peak power density as high as 564 mW cm(-2) was obtained at 500 degrees C based on a 20 mu m thick Sm0.2Ce0.8O1.9 electrolyte by adopting SSC cathode. (C) 2008 Elsevier B.V. All rights reserved