The effect of calcium on the properties of SmBa1−xCaxCoCuO5+δ as a cathode material for intermediate-temperature solid oxide fuel cells

The effect of calcium on the properties of SmBa 1–x Ca x CoCuO 5+δ (x = 0.0–0.3) as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) is evaluated systematically. Samples exhibit a highly crystalline double perovskite phase, and their cell volumes decrease as x is changed from 0.0 to 0.3. The oxygen content and average thermal expansion coefficient (TEC) of SmBa 1–x Ca x CoCuO 5+δ decreases as the calcium content increased. An average TEC of as low as 15.3 × 10 −6 °C −1 is obtained for SmBa 0.7 Ca 0.3 CoCuO 5+δ . The area specific resistances at 700 °C decrease by approximately 50% when the calcium content is increased from x = 0.0 (0.173 Ω cm 2 ) to x = 0.3 (0.086 Ω cm 2 ). The maximum power densities of SmBa 1−x Ca x CoCuO 5+δ -based single cells at 800 °C increase from 635 mW cm −2 (x = 0.0) to 939 mW cm −2 (x = 0.3).