Synergistically boosting high-temperature CO2 electrolysis performance via high-entropy engineering and anion doping strategy

Solid oxide electrolysis cell (SOEC) is recognized as a promising and efficient energy conversion technology by converting CO 2 into CO for achieving carbon neutrality. However, the cathode materials with insufficient electrocatalytic activity and stability greatly limit its large-scale commercial application. Herein, a synergistic strategy of high-entropy engineering and anion doping is proposed to develop a novel highly efficient and stable cathode material for CO 2 electrolysis in SOEC. Fluorine doped high-entropy perovskite La 0.6 Sr 0.4 Fe 0.3 Co 0.2 Ni 0.2 Mn 0.2 Mo 0.1 O 3-δ (LSFCNMM-F) is successfully synthesized to boost the CO 2 electrolysis performance. F doping can weaken the strength of metal-oxygen bond, increasing the concentration of oxygen vacancies, which significantly promotes the CO 2 adsorption and activation. Accordingly, F-doped high-entropy perovskite LSFCNMM-F cathode exhibits outstanding electrochemical performance and excellent stability for CO 2 electrolysis in SOEC. Compared to the pure high-entropy perovskite LSFCNMM, F-doped high-entropy perovskite LSFCNMM-F achieves 24.5 % improvement in current density with a remarkable value of 1.78 A/cm 2 at 1.5 V and 800 °C, surpassing most of the reported cathode materials in SOEC field. Moreover, the single cell with LSFCNMM-F cathode exhibits better long-term stability than that with pure high-entropy perovskite LSFCNMM cathode during 100 h operation at 1.2 V and 750 °C, owing to the inhabitation of Sr segregation on the electrode surface after F doping. The results from this study provide insights into the role of synergistic strategy for combining high-entropy engineering and anion doping in developing highly efficient and stable cathode for CO 2 electrolysis using SOEC technology.