(La,Sr)(Ti,Fe)O3−δ perovskite with in‐situ constructed FeNi3 nanoparticles as fuel electrode for reversible solid oxide cell

Summary As a promising technology to address the energy storage challenge, reversible solid oxide cell (RSOC) plays a vital role in conversion between chemical energy and electrical power. Over the last several decades, developing high performance fuel electrodes suitable for reversible operation have attracted extensive attentions. This work develops La0.1Sr0.85Ti0.35Fe0.6Ni0.05O3−δ which is an A‐site deficient design with B‐site having additional 5% nickel as the fuel electrode through in‐situ metal exsolution. The in‐situ exsolution process results in FeNi3 alloy particles, about 40 nm in size, while maintaining the perovskite structure of the parent oxide. The FeNi3 nanoparticles greatly improve the electrochemical performance as RSOC fuel electrode such as reducing the interfacial polarization resistance at 800°C by 13.6%, increasing the peak power density by 19% in the fuel cell mode and increasing the current density by 30% in the electrolysis mode. Furthermore, RSOC operation is demonstrated by 20‐cycle reverse tests that are conducted by switching between the fuel cell and electrolysis modes. The stable RSOC performance indicates that La0.1Sr0.85Ti0.35Fe0.6Ni0.05O3−δ with in‐situ constructed FeNi3 nanoparticles is a potential fuel electrode material for RSOC. La0.1Sr0.85Ti0.35Fe0.6Ni0.05O3‐γ with in‐situ constructed FeNi3 nanoparticles is a potential fuel electrode material for reversible solid oxide cell. The exsolved FeNi3 nanoparticles significantly boost the electrocatalytic activity and remain stable in the 20‐cycle of reverse operation between the fuel cell and electrolysis modes.