New strategy for boosting cathodic performance of low temperature solid oxide fuel cells via chlorine doping

To enhance the performance and widespread use of solid oxide fuel cells (SOFCs), addressing the low-temperature (< 650 °C) electrochemical performance and operational stability issues of cathode materials is crucial. Here, we propose an innovative approach to enhance oxygen ion mobility and electrochemical performance of perovskite oxide by substituting some oxygen sites with chlorine anions. The designed SrTa0.1Fe0.9O3-δ-xClx (x = 0.05 and 0.10) exhibits improved performance compared to SrTa0.1Fe0.9O3-δ (STF). SrTa0.1Fe0.9O2.95-δCl0.05 (STFCl0.05) shows the lowest area-specific resistance (ASR) value on Sm0.2Ce0.8O1.9 (SDC) electrolyte. At 600 °C, STFCl0.05 achieves an ASR value of 0.084 Ω·cm2, and a single cell with STFCl0.05 reaches a higher peak power density (PPD) value (1143 mW·cm-2) than that with STF (672 mW·cm-2). Additionally, besides exhibiting excellent oxygen reduction reaction (ORR) activity at lower temperatures, the STFCl0.05 cathode demonstrates good CO2 tolerance and operational stability. Symmetrical cell operation lasts for 150 h, and single cell operation endures for 720 h without significant performance decline. The chlorine doping approach effectively enhances ORR activity and stability, making STFCl0.05 a promising cathode material for low-temperature SOFCs.