Boosting the CO2 electrolysis performance using high entropy stable La0.2Pr0.2Sm0.2Sr0.2Ca0.2Fe0.9Ni0.1O3-δ electrode for symmetric solid oxide electrolysis cells

Abstract

The development of CO2 electrolysis using symmetric solid oxide electrolytic cells (SSOECs) requires the identification of electrode materials with high catalytic activity and stability. Herein, we designed and synthesized a high entropy perovskite electrode material La0.2Pr0.2Sm0.2Sr0.2Ca0.2Fe0.9Ni0.1O3-δ (LPSSCFN), exhibiting an orthorhombic perovskite with a uniform compositional distribution without any elemental segregation. Compared with Sm0.5Sr0.5Fe0.9Ni0.1O3-δ (SSFN), LPSSCFN exhibits higher stability and chemical compatibility in the CO2 atmosphere. Symmetric cells using LPSSCFN-Ce0.8Gd0.2O1.9 (GDC) and SSFN-GDC were prepared and then tested for CO2 electrolysis, respectively. High electrolytic current density of 446 mA cm−2 using LPSSCFN-GDC symmetric electrode can be obtained at 1.8 V and 750 °C, while it is only 373 mA cm−2 for the similar symmetric cells with SSFN-GDC. More importantly, the high entropy LPSSCFN-GDC symmetric electrode exhibit excellent long-term electrolysis stability with a decay rate of 0.6 % h−1, much lower than that of SSFN-GDC (1.3 % h−1). All the experimental results demonstrate that the high entropy stability strategy can effectively boost the CO2 electrolysis performance for symmetric solid oxide electrolysis cells.