Gadolinium-doped SrFeO3 as a highly active and stable electrode for symmetrical solid oxide fuel cells

Symmetrical solid oxide fuel cells (SSOFCs) with identical electrodes have gained interesting attention because of their simplified fabrication procedure and reduced processing costs. However, their development is limited by their electrocatalytic activity and stability of the electrode materials used. Here, we report a prototypical SrFeO-based perovskite oxide with formula GdSrFeO (GSF) as a highly effective SSOFC electrode material. It was found that A-site Gd substitution in SrFeO greatly improved its structural stability under reducing atmosphere. Furthermore, doping Gd was able to significantly enhance the electrochemical activity, achieving area-specific resistances of 0.18 Ω cm for the cathode and 0.003 Ω cm for the anode at 800 °C, respectively. The lower polarization resistance could be attributed to the abundant surface oxygen species through the Gd-doping in SrFeO. Benefiting from superior electrochemical activity and structural stability, the symmetrical cell with GSF-0.2 electrode showed reasonable stability and electrochemical performance. These results show that the developed GSF perovskite oxide may be a promising candidate as electrode material for symmetrical SOFCs.