Zn-Doped Ruddlesden–Popper-Type Layered Perovskite La 2 Fe 1– x Zn x O 4 as Efficient Fuel Electrodes for Enhanced CO 2 –CO Mutual Conversion in Reversible Solid Oxide Cells

A reversible solid oxide cell (RSOC) enables efficient interconversion between CO and CO 2, and it is recognized as a highly promising device for energy storage and conversion. To enhance the kinetics of CO 2 to CO conversion, B-site Zn-doped Ruddlesden–Popper (RP)-type layered perovskite fuel electrodes, specifically La 2 Fe 1– x Zn x O 4 (x = 0, 0.05, and 0.1), are fabricated and deployed as the fuel electrode. The characterization results reveal that Zn doping can significantly boost the concentration of oxygen vacancies and promote the charge transfer process. When the Zn doping amount is 0.1, the current density of the single cell with this fuel electrode is 0.73 A cm –2 at 800 °C with a voltage of 1.5 V. Furthermore, the maximum power density is 123 mW cm –2 in a 50% CO–50% CO 2 atmosphere. Additionally, at 800 °C and 1.5 V, a single cell composed of the La 2 Fe 0.9 Zn 0.1 O 4 fuel electrode demonstrates a current density of 1.41 A cm –2 for CO 2 electrolysis, marking an 85.5% enhancement in performance over that of the La 2 FeO 4 fuel electrode. Consequently, Zn doping elevates the electrocatalytic performance of RP-type layered perovskite fuel electrodes, offering a novel strategy for advancing fuel electrode material development.