D. Li, X. Wang * and Z.-S. Wu *

Advanced Energy Materials, 2026, accepted.

Seawater batteries (SWBs) have emerged as promising aqueous energy storage systems primarily owing to their intrinsic safety and environmental sustainability. As a naturally abundant and cost-effective electrolyte source, seawater exhibits considerable economic benefits and potential applications. Nevertheless, the practical applications of SWBs are constrained by several challenges, including the complex multicomponent ionic composition, high corrosivity, and the narrow electrochemical stability window of seawater electrolytes. Despite these constraints, a systematic summary regarding the targeted design of electrode materials specifically tailored for seawater-based electrolytes remains lacking. In this review, we first elucidate how the physicochemical properties of seawater give rise to distinct SWB configurations and define the corresponding requirements for electrode materials. Subsequently, we provide a comprehensive discussion of rational design strategies to enhance electrochemical performance of SWBs, focusing on the modulation of electron-ion transport pathways with electrode materials, electrolyte engineering, and interfacial regulation to achieve fast kinetics and thermodynamics in high chloride ions concentration with complex interplay. Furthermore, potential application scenarios of SWBs are outlined in accord with the configuration prototypes. Finally, we highlight the key challenges and provide future research directions for the development of advanced materials toward high-performance and durable SWBs.