Anion Fluorine-Doped La0.6Sr0.4Fe0.8Ni0.2O3-δ Perovskite Cathodes with Enhanced Electrocatalytic Activity for Solid Oxide Electrolysis Cell Direct CO2 Electrolysis

As a promising and profound device for energy conversion, a solid oxide electrolysis cell (SOEC) can efficiently convert CO2 to CO, realizing chemical storage of renewable energy. However, developing active and stable cathode catalysts for the CO2 reduction reaction (CO2-RR) is critical for SOECs. Herein, to enhance the electrocatalytic performance of a La0.6Sr0.4Fe0.8Ni0.2O3-delta (LSFN) cathode catalyst for CO2-RR, fluorine doping is investigated as anion doping for O-site in the LSFN perovskite lattice. The results confirm that F-doped La0.6Sr0.4Fe0.8Ni0.2O3-delta (LSFNF0.1) has more oxygen vacancies and better CO2 adsorption ability (approaching 4 times than LSFN). The cell with LSFNF0.1 can achieve a maximum electrolysis current density of 1.93 A.cm(-2) at 1.8 V at 850 degrees C, with a Rp of 0.275 O.cm(2) at OCV. Meanwhile, the cell possesses good durability for more than 60 h at an electrolysis current density of 0.6 A.cm(-2) without apparent degradation. Mechanistic analysis indicates that F-doping can accelerate the formation of intermediates during electrolysis, indirectly promoting the reaction of the bidentate carbonate (rate-determining step). This work shows that anion-doped LSFNF0.1 is a promising cathode for SOEC direct CO2 electrolysis and provides a potential route for the cathode catalyst development of SOECs.

Automated summary

Solid oxide electrolysis cell (SOEC) is a promising device for energy conversion by efficiently converting CO2 to CO for renewable energy storage. Developing active and stable cathode catalysts for CO2 reduction reaction (CO2-RR) is crucial for SOECs. In this study, fluorine doping on La0.6Sr0.4Fe0.8Ni0.2O3-delta (LSFN) cathode catalyst was investigated to enhance its electrocatalytic performance for CO2-RR. The results showed that F-doped LSFN had more oxygen vacancies and better CO2 adsorption ability, leading to improved electrolysis current density and durability. Mechanistic analysis revealed that F-doping promoted the formation of intermediates and the rate-determining step of the reaction. This work demonstrates the potential of anion-doped LSFNF0.1 as a promising cathode catalyst for SOEC direct CO2 electrolysis and provides insights for future development of cathode catalysts for SOECs.