An efficient and prospective self-assembled hybrid electrocatalyst for symmetrical and reversible solid oxide cells

Abstract

In view of the high catalytic activity, enhanced oxygen-ion transport and good stability, the self-assembled hybrid electrocatalyst can be used for symmetrical and reversible solid oxide cells (RSOCs). Herein, a new Ni-free ceramic fuel electrode can be obtained by in situ annealing the orthorhombic perovskite Pr0.6Sr0.4FeO3-δ (PSF) in H2 at 850 °C for 2 h, consisting of orthorhombic perovskite matrix with nano Ruddlesden–Popper oxide (RP/O-PSF). Symmetrical RSOCs consisting of RP/O-PSF fuel electrode, La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolyte and PSF air electrode (PSF|LSGM|PSF) were fabricated and the electrochemical performance was evaluated. The maximum power density of the cell under solid oxide fuel cell (SOFC) mode is 591 mW/cm2 at 800 °C, and the current density of the cell under solid oxide electrolysis cell (SOEC) mode is -1388 mA/cm2 at 800 °C with an applied electrolysis voltage of 1.6 V. The polarization resistances of cell under SOFC mode and SOEC mode are 0.152 Ω cm2 (OCV-0.2 V) and 0.126 Ω cm2 (OCV + 0.2 V), respectively, demonstrating an excellent catalytic activity of RP/O-PSF towards the water electrolysis process compared with hydrogen oxidation reaction (HOR) owing to the accelerated transfer rate of oxygen ions. In addition, the desirable long-term stability indicates the fact that RP/O-PSF hybrid electrode is such a suitable and prospective candidate for symmetrical and reversible solid oxide cells.