Deficiency-Tuned NiFe Alloy Exsolution in LaCrO₃-Based Perovskite Cathode of SOEC with Enhanced Performance for H₂O–CO₂ Coelectrolysis

Solid oxide electrolysis cells (SOECs), characterized by their high energy conversion efficiency, present great potential in value-added syngas and hydrogen production through H2O–CO2 coelectrolysis. However, the undesirable long-term cell stability problem limits their large-scale practical application. In this work, a simple deficiency-tuning strategy for NiFe alloy exsolution from the (La1–xSrx)1–yCr0.8Fe0.1Ni0.1O3−δ perovskite fuel electrode is investigated to enhance the electrochemical performance of the cell. The Sr content in the A-site is tuned to improve the oxygen vacancy concentration and basicity of the perovskite, while the A-site deficiency (y) is also regulated to investigate the influence of various exsolved phases on the coelectrolysis performance. The study determines that with the stoichiometry optimized (La0.9Sr0.1)0.8Cr0.8Fe0.1Ni0.1O3−δ ((LS)0.8CFN) fuel electrode, the corresponding LSGM electrolyte-supported cell exhibits excellent coelectrolysis electrochemical performance under a 40%H2-30%H2O-30%CO2 atmosphere. Additionally, the cell with the (LS)0.8CFN fuel electrode acquires the highest current density of 0.640 A cm–2 at 1.3 V and 700 °C, as well as good 100 h stability at 400 mA cm–2. The study confirms that the finely exsolved alloy nanoparticles with robust embedded conjunction with the perovskite matrix can synergistically improve the catalytic activity and stability of the fuel electrode, providing practical and feasible strategies in exploring fuel electrode materials with active metal exsolution.