All Bio‐Based Noncorrosive Hygroscopic Hydrogel Enables Passive Cooling of Electronic Devices

The emergence of artificial intelligence (AI) technologies has greatly increased the importance of thermal management in electronic systems. Conventional cooling strategies require substantial amounts of coolant, particularly water, whose demand is rapidly increasing. Here, we propose a sorption‐based passive evaporative cooling system using an all‐nature‐derived hygroscopic polymer film, which can supplement conventional cooling systems and substantially reduce their energy consumption. In a simulated laboratory‐scale demonstration, the system achieved a maximum cooling power of (), with a maximum temperature reduction of 18.2 °C. The cooling performance was also maintained during repeated cyclic simulations. In addition, the incorporation of an organic ionic liquid as a hygroscopic component, instead of conventional metal salts, endowed the film with excellent flexibility, elongation, adhesiveness, and noncorrosive properties. Therefore, the proposed sorption‐based passive cooling system holds great potential for assisting conventional electronic cooling systems while significantly reducing energy demand.