Nowadays, effective utilization of CO2has been a worldwide issue. Among numerous CO2conversion devices, solid oxide electrolysis cells (SOECs) have drawn special attention due to their high energy conversion efficiency, great potential in carbon cycling, and low environmental impacts. Compared with the typical ones taking asymmetrical configuration, symmetrical SOECs adapting the same oxide materials as both the cathode and anode have the advantages of simplified fabrication procedures, reduced processing costs and minimized compatibility issues. As the appropriate sites for CO2conversion, cathodes play the key role in determining the performance of symmetrical SOECs, and thus, attract more attention to improve their electrocatalytic behaviors and enduranceviaexploring novel materials. In this work, Eu-doped Ruddlesden-Popper (R-P) oxide, SrEu2Fe2O7(SEF), is applied as an electrode material for symmetrical SOECs to directly electrolyze pure CO2. The outstanding structural stability and excellent electrochemical activity of the SEF electrode under both oxidizing and reducing atmospheres are demonstrated, and relatively low polarization resistances of 0.07 Ω cm2in air and 0.48 Ω cm2in 2CO2-CO mixtures at 800 °C are observed. A great current density of 1.27 A cm−2at an applied voltage of 1.5 V and 800 °C is achieved on this symmetrical SOEC. An extremely low polarization resistance of 0.27 Ω cm2is also observed under open circuit conditions. Further, the symmetrical button cell has demonstrated excellent stability within 260 h of the long-term CO2electrolysis test.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)