Performance of double perovskite symmetrical electrode materials Sr2TiFe1–xMoxO6–δ (x = 0.1, 0.2) for solid oxide fuel cells

Abstract

Symmetrical solid oxide fuel cells (SSOFCs) show many advantageous features of simplifying fabrication process, minimizing interdiffusion between components and enhancing coking and sulfur tolerance by operating the anode as the cathode. In this paper, the double-perovskite Sr2TiFe0.9Mo0.1O6–δ (STFM01) and Sr2TiFe0.8Mo0.2O6–δ (STFM02) oxides are synthesized by the traditional solid-state reaction and assessed as symmetrical electrodes. Both of the two materials show cubic double perovskite structure with outstanding structural stability, well chemical compatibility and matched thermal expansion coefficients with the common electrolytes in oxidizing and reducing atmospheres under SOFC operating temperatures. From the electrochemical performance, the electrolyte-supported single cell with STFM01 electrode presents the maximum power densities of 573 mW cm−2 in H2 and 361 mW cm−2 in complex hydrocarbon fuels containing H2S at 850 °C, respectively. The electrochemical stability test exhibits that the STFM01 sample showed no any degradation in H2 and acceptable degradation in hydrocarbon fuels, and STFM02 sample showed no any deterioration during 30-h test in hydrocarbon fuels, which implies that the STFM01 and STFM02 materials had remarkable ability of resisting carbon deposition and sulfur poisoning than the traditional anode material. The efficient and relatively stable double perovskite symmetrical electrodes are much more promising candidate materials for SSOFCs and are beneficial for realizing commercialization of SOFC.