Bioinspired Design of Thermally Conductive Radiative Cooling Structure for Outdoor Electronic Devices

Abstract As the outdoor electronic devices generate considerable heat due to their compact packaging and increasingly powerful designs, thermal management has emerged as a pivotal aspect to prolong the lifespan and ensure the reliability. Passive radiative cooling technology offers an alternative pathway without carbon emissions. Nevertheless, a persistent challenge remains in effectively cooling outdoor electronic devices, especially under direct sunlight. Herein, a bioinspired design of thermally conductive radiative cooling structure composed of hexagonal boron nitride (h‐BN) and polyvinyl alcohol (PVA) is demonstrated. This Bio‐h‐BN/PVA composite film possesses a highly aligned layered structure, analogous to that of the natural abalone shell, which manifests a solar reflectance of 96.5%, a broadband mid‐infrared emissivity of 0.95 and an exceptional thermal conductivity of 23.6 W m −1 K −1 . The integration of the Bio‐h‐BN/PVA composite film into outdoor electronic device yields a thermal equilibrium temperature reduction of 13.49 °C compared to bare device, under solar irradiance of ≈650 W m −2 and an input power density of 3000 W m −2 . This work provides both computational and experimental insights into the substantial impact of non‐radiative heat transfer on the thermal management of outdoor electronic devices, thereby facilitating the development of effective strategies for achieving above‐ambient cooling in practical applications.