Reversible protonic ceramic cells with symmetrical electrode: A case of La0.3Sr0.7Fe0.7Cr0.3O3-δ

Using symmetrical electrodes with the same material compositions can simplify the manufacturing process, reduce cost, and enhance the stability and reliability of solid oxide cells. Herein, we report for the first time the potential application of the La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3-δ (LSFC) perovskite as a symmetrical electrode for reversible protonic ceramic cells (RPCCs). The LSFC exhibits robust chemical stability in oxidizing and reducing environments and favorable chemical compatibility with BaZr 0.4 Ce 0.4 Y 0.15 Zn 0.05 O 3-δ electrolyte below 950 °C. Using LSFC as a symmetrical electrode, the electrolyte-supported RPCC delivers a maximum power density of 76 mW cm −2 in fuel cell (FC) mode at 700 °C, and a maximum current density of 30 mA cm −2 in electrolysis cell (EC) mode at 1.5 V; no significant degradation is shown under both FC and EC modes during 100 h continuous operation. The LSFC shows remarkably low polarization resistances (R p ) of 0.06 and 0.07 Ω cm 2 at 700 °C in dry and wet air, which allows it to be used directly as an air electrode; while it is 3.46 Ω cm 2 at 700 °C in 5%H 2 /Ar, which needs to improve its catalytic activity to enhance the overall performance of symmetrical electrode. These results allow us to propose a feasible strategy for applying symmetrical electrodes in RPCCs.