Recent Advances in Hydrogel Materials for Electrochemical Energy Storage

Energy storage and conversion are vital to societal development and scientific and technological advancements. Electrode and electrolyte, as the core components of energy storage devices, directly influence their key performance metrics. Hydrogel materials exhibit outstanding properties and tunability, and can be prepared through efficient, versatile, and straightforward methods. Their intrinsic characteristic——— including ionic and electronic conductivity, mechanical strength, responsiveness, and swelling behavior, make them ideal candidates for electrodes or electrolytes with tailored functionalities. Moreover, the unique cross-linking and three-dimensional network structure of hydrogels significantly enhances their mechanical robustness and electrochemical performance. This review first introduces the basic characteristics, classification, adjustable properties, and preparation methods of hydrogel materials. It then discusses their application in energy storage devices, including lithium-ion batteries and supercapacitors, highlighting their unique physicochemical properties and structural advantages. Finally, current challenges in hydrogel materials to sustainable energy storage are summarized, and future development prospects are outlined.