Camel-Fur-Inspired Graphite-Based Hygroscopic Membrane for Passive Air Cooling with Ultrahigh Cooling Power

Earth's temperature has risen by ≈0.18 °C per decade since 1981 and year 2022 is the sixth-warmest year on record. The exploration of cooling strategies that operate with less energy consumption is thus highly desirable. Through this project, a camel-fur-inspired passive membrane encapsulated sorbent cooler that can periodically absorb moisture from the atmosphere and release it for daytime evaporative cooling, leading to effective regulation of building temperature without additional energy input is demonstrated. This sorbent cooler with high sorption capacity is made of anhydrous salt and modified expanded graphite and further encapsulated by a breathable porous membrane. This novel material is shape-stabilized, and it has excellent cycling performance, and remarkable water adhesion ability. In this evaporative-cooling demonstration, the average cooling power of the camel-fur-inspired sorbent can reach up to 630 W m⁻², which is much higher than the radiative cooling approach. This theoretical model implies that the proposed sorbent cooler has the potential to cut down cooling energy carbon emission by 61% to 87.83% when compared to emissions released from cooling energy usage in reference buildings. This nature-inspired approach paves a new way for efficient space cooling without extra water supply and with minimized energy consumption. © 2024 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.