In-situ growth of nanoparticles-decorated double perovskite electrode materials for symmetrical solid oxide cells

The development of symmetrical solid oxide fuel cells (SSOFCs) can accelerate the commercialization of SOFCs because it can reduce the fabrication cost, improve the thermomechanical compatibility between the electrolyte and electrodes, and enhance the ability of resisting coking and sulfur poisoning. In addition, it is more convenient to switch between the SOFC mode and the solid oxide electrolysis cell (SOEC) mode for the SSOFCs. In this work, we report a new family of double perovskite symmetrical electrodes Sr2Ti1–xCoxFeO6 (x = 0, 0.1, 0.2, 0.3, STCF) for SSOFCs. The Sr2Ti0.8Co0.2FeO6 (STC02 F) electrode can be exsoluted with the cobalt-iron alloy nanoparticles and can maintain the double perovskite structure in reducing atmosphere. The STC02 F electrode also has good chemical compatibility with La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte. The polarization resistance (Rp) values of the STC02F-based symmetrical cells are 0.124 and 0.380 Ω cm2 at 800 °C in air and in hydrogen, respectively. The output power densities of the single cell with the configuration STC02 F/LSGM (270 μm)/STC02 F reach 555, 180, 404, and 390 mW cm–2 at 800 °C using H2, liquefied petroleum gas, C2H5OH, and CH3OH, respectively. Moreover, the symmetrical cell with STC02 F electrode shows good electrochemical performance and stability for the electrolysis of H2O or CO2 and co-electrolysis of H2O/CO2 at intermediate temperatures for SOECs.