Emerging Materials and Future Strategies for Solid Oxide Electrochemical Cells

ABSTRACT Solid oxide electrochemical cells (SOC), encompassing fuel‐cell, electrolysis, and reversible operating modes, represent a pivotal technology for high‐efficiency conversion between electrical energy and chemical fuels. However, practical deployment at intermediate‐temperatures (IT, 600–800°C) is constrained by intertwined limitations in ionic transport, surface reaction kinetics, and thermo–chemical stability. This review summarizes and analyzes the recent developments in SOC electrodes and electrolytes through a unified structure‐defect‐property‐durability framework. Emphasis is placed on how crystal symmetry, lattice distortions, and defect chemistry dictate charge‐carrier concentrations, oxygen and proton migration pathways, and interfacial compatibility under realistic oxidizing and reducing environments. By correlating electrochemical performance with oxygen‐vacancy formation energetics, transport coefficients, and degradation processes such as cation segregation and secondary‐phase evolution, the potential of different materials for SOC was further analyzed. Finally, prospective strategies involving multifunctional electrolyte architectures, defect and interface‐engineered electrodes, and multiscale microstructural control are outlined, offering guidance to the rational design of durable, high‐performance SOC systems capable of sustained operation in the IT regime.