Cobalt-based double-perovskite symmetrical electrodes with low thermal expansion for solid oxidefuel cells

The fabrication of a solid oxide fuel cell (SOFC) with symmetrical anode/cathode electrodes is a practical strategy to reduce strain, promote co-sintering of the electrodes, and hence to improve stability and reliability. Non-stoichiometric Sr2Co1+xMo1−xO6 (x = 0.1, 0.15, 0.2) (SCMO) double perovskites are designed to be used as symmetrical anode/cathode electrodes for symmetrical SOFCs with La0.8Sr0.2Ga0.83Mg0.17O3 (LSGM) as electrolyte. As an individual anode or cathode, SCMO shows considerable electrochemical performance. A typical cell with Sr2Co1.15Mo0.85O6 as the symmetrical anode/cathode electrodes, the maximum power density reaches as high as 460 mW cm−2 at 800 °C. The thermal expansion coefficient (TEC) of SCMO ranges from 6 × 10−6 to 15 × 10−6 K−1 from room temperature to 900 °C, matching well that of the conventional LSGM electrolyte.