Cobalt-based double-perovskite symmetrical electrodes with low thermal expansion for solid oxide fuel 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 Sr(2)Co(1+x)Mo(1-x)O(6) (x = 0.1, 0.15, 0.2) (SCMO) double perovskites are designed to be used as symmetrical anode/cathode electrodes for symmetrical SOFCs with La(0.8)Sr(0.2)Ga(0.83)Mg(0.17)O(3) (LSGM) as electrolyte. As an individual anode or cathode, SCMO shows considerable electrochemical performance. A typical cell with Sr(2)Co(1.15)Mo(0.85)O(6) as the symmetrical anode/cathode electrodes, the maximum power density reaches as high as 460 mW cm(-2) at 800 degrees C. The thermal expansion coefficient (TEC) of SCMO ranges from 6 x 10(-6) to 15 x 10(-6) K(-1) from room temperature to 900 degrees C, matching well that of the conventional LSGM electrolyte.