On Fe-based perovskite electrodes for symmetrical reversible solid oxide cells – A review

Symmetrical reversible solid oxide cells (SRSOCs) employing identical materials and structure for both electrodes have garnered significant attentions due to their numerous benefits, including a simplified and straightforward preparation process, excellent chemical and thermo-mechanical compatibility between the electrolyte and electrodes, as well as improved resistance to carbon deposition and sulfur poisoning. While various challenges persist to be solved, including sufficiently enough redox activities, improved long-term stability, and enhanced operating performance. In this review, state-of-the-art research progress is highlighted and discussed for the electrodes of SRSOCs employing Fe-based perovskites, in terms of single perovskites, double perovskites and RP-type perovskites with various modification methods (including doping, composing, infiltration and in-situ exsolution methods). Commonalities and differences among these Fe-based perovskites are also outlined for reviewed SRSOCs' electrode materials. Trends and potentials for enhancing stability in both fuel cell and electrolysis modes are discussed, aiming to identify the redox-stable electrode materials with favorable mechanical properties. Furthermore, the prospect for Fe-based SRSOCs lies in improving redox conductivity and long-term stability through RP-type/double perovskite structures by employing appropriate modification methods based on modeling/simulation methods combined with experimental approaches.