Recent Progress in Photoelectrode Materials for Solar‐Coupled Metal–Air Seawater Batteries

Metal–air seawater batteries have emerged as promising energy‐storage systems owing to their high theoretical energy density, intrinsic safety, economic viability, and compatibility with natural seawater or seawater‐derived electrolytes. However, sluggish oxygen electrocatalysis and poor cathode durability in chloride‐rich seawater cause large polarization, low energy efficiency, and limited stability. Coupling solar energy with these batteries offers an effective strategy to accelerate cathode reactions through photoelectric and photothermal effects. In view of the rapid progress in this emerging field, this Review summarizes recent advances in solar‐coupled metal–air seawater batteries, focusing on device configurations, working principles, photoelectrode materials, and representative battery systems. Inorganic, organic, and composite semiconductor photoelectrodes are discussed in terms of light harvesting, charge separation, oxygen electrocatalysis, and seawater compatibility. Recent advances in solar‐coupled Na–air, Zn–air, and value‐added seawater batteries are further highlighted. Finally, key challenges related to photoelectrode stability, interfacial microenvironments in seawater, performance evaluation, and device integration are outlined to guide the development of efficient and durable solar‐coupled metal–air seawater batteries.