High-Entropy Li-doped rock salt catalyst for low-Temperature ceramic fuel cells

Ceramic fuel cells (CFCs) are highly efficient for energy conversion at temperatures below 550 °C, reducing thermal stress and improving longevity compared to traditional high-temperature fuel cells. The main challenge is developing efficient, stable electrodes with high redox activity at low temperatures. This study developed Li-doped HEO (Co, Cu, Ni, Na, Mg, and Zn) catalyst with a rock salt structure for low-temperature ceramic fuel cells (LT-CFCs). The Li-HEO, used as symmetrical electrodes with Gd_0.1Ce_0.9O₂ (GDC) electrolyte, demonstrating a peak power density of 683 mW/cm² and open circuit voltage (OCV) of 1.036 V at 550 °C. Experimental techniques such as electrochemical impedance spectroscopy (EIS) and Distribution of relaxation time (DRT) analyses were employed to study electrochemical proton injection and reaction processes. The Li-doped HEO showed significant potential as a symmetrical electrode material, exhibiting high stability and enhanced catalytic function, with oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) activities of 0.215 Ω.cm² and 0.185 Ω.cm², respectively. The Li-HEO electrodes also display exceptional durability at 520 °C. These findings highlight the promise of Li-HEO materials in low-temperature fuel cell technologies governing charge transfer in electrode reactions and facilitate transport in electrolyte processes.