Dual-Encapsulated Nanocomposite for Efficient Thermal Buffering in Heat-Generating Radiative Cooling

Radiative cooling has been considered an innovative passive method to resolve the problem of overheating of electronic devices. However, it is inefficient for cooling huge heat generation components. Herein, we report a dual-encapsulated nanocomposite (DEN) by integrating radiative cooling and phase-change materials (PCMs) for thermal buffering in heat-generating radiative cooling. The leak of PCMs is avoided by a simple dual-encapsulated structure with a three-dimensional (3D) interconnected cellular-like network structure and radiative cooling layer on the surface, 75% superior to the state-of-the-art single encapsulation designs. Additionally, our DEN not only shows outstanding optical properties with strong solar reflection (R̅solar = 0.96) and IR-selective emission (ε̅8–13 μm = 0.94 and ηε = 1.15) but also exhibits high phase-change enthalpy (ΔHm = 192.2 J/g, ΔHc = 175.7 J/g), enabling remarkable radiative cooling capability and desirable thermal energy peak shaving and valley filling effect. Outdoor experiments demonstrate that DEN achieves a temperature drop up to 23 °C compared to the control group without DEN coverage when electronics generate heat. This dual-encapsulated nanocomposite provides a novel strategy and solution for outdoor passive thermal management.