Hierarchical Janus Metafabric With LiCl@UiO-66 for Humidity-Resilient Radiative and Evaporative Cooling

Passive radiative cooling provides a sustainable, zero-energy cooling pathway, yet it faces a fundamental challenge in humid or cloudy conditions due to the blockage of the atmospheric transparency window and increased downward atmospheric radiation. Herein, we present a hierarchical Janus bilayer metafabric (TS/PLU) that synergistically combines radiative and evaporative cooling for thermal management with humidity resilience. Integrating a hydrophobic TPU/h-SiO 2 reflection layer with a hygroscopic PAN/LiCl@UiO-66 regulation layer achieves superior solar reflectance (>96%), high atmospheric-window emissivity (96.6%), and moisture capture and evaporation. Crucially, a “harvest-storage-release” mechanism is enabled by UiO-66-confined LiCl, mitigating deliquescence and salt leakage while facilitating heat dissipation even when radiative power is attenuated by high humidity. Asymmetric wettability ensures unidirectional water transport, preserving the radiative function of the hydrophobic top layer. Outdoor tests demonstrate a maximum sub-ambient temperature reduction of 13.4°C under sunny conditions, with a net radiative cooling power of 132.87 W m −2 . The LiCl@UiO-66 incorporation contributes an additional 5.1°C cooling enhancement relative to non-hygroscopic controls. Combined with mechanical robustness (≈370% elongation) and washing durability, this multimodal strategy offers a material-level proof of concept for thermal management featuring humidity resilience and shows potential relevance to personal cooling, outdoor thermal protection, and building-envelope cooling.