High‐performance and wide relative humidity passive evaporative cooling utilizing atmospheric water

Abstract Global warming and increased living standards have rapidly increased the demand for cooling systems. Meeting this demand in less economically developed areas is highly challenging due to a lack of electricity. In this paper, we have demonstrated a high‐performance and wide relative humidity (RH) solar‐driven evaporative cooling strategy that uses only atmospheric water. Developed here for the first time, we designed a metal–organic framework (MOF‐801) based composite with a high‐performance atmospheric water absorption across a wide range of RH. The as‐synthesized composite can adsorb atmospheric water up to ~22% (~80%) of its weight at an RH@28% (~70%). Our demonstration has shown that the corresponding cooling powers range from 136 to 344 W/m 2 in a wide range of RH and solar intensities, and the passive cooling temperature is up to 14°C lower than the device's reference counterpart. Our study thus proposes a solar‐driven cooling coating with high cooling powers across a wide range of RH based on an as‐synthesized composite, which pinpoints a pathway to replace traditional compression‐based cooling systems (e.g., air conditioners) and which will also have a significant impact in future global energy consumption.