A Leakage‐Proof Wrapped Cooler with Daytime Radiative Cooling and Efficient Thermal‐Shock Resistance for Outdoor Electronics Thermal Management

Abstract Outdoor electronics are simultaneously subject to constant solar radiation and instantaneous thermal shock, thus urgently requiring effective thermal management. However, commonly adopted radiative cooling has an issue of low cooling power and phase change temperature control technology suffers from materials leakage, which cannot meet the increasing demands for outdoor electronics. To address these problems, a leakage‐proof wrapped cooler that integrates radiative cooling and latent heat storage is proposed to achieve sub‐ambient cooling and efficient thermal‐shock resistance. The wrapped cooler is designed by directly wrapping paraffin wax (PW) phase change material (PCM) within a hexagonal boron nitride/polydimethylsiloxane (h‐BN/PDMS) coating, possessing leakage‐proof property during force and thermal shock. The wrapped cooler can achieve an average sub‐ambient temperature drop of 4.8 °C under direct sunlight. Moreover, a maximum temperature drop of 35.3 °C can be achieved for the heater covered with the wrapped cooler when experiencing 2000 W m −2 thermal shock, mainly due to the temperature‐pinning effect of PCM and the high thermal conductivity of h‐BN/PDMS coating. The wrapped cooler that integrates radiative cooling with latent heat storage provides an effective way for protecting outdoor electronics from solar radiation and thermal‐shock damage, thereby advancing passive thermal management technologies toward practical applications.