Vertically oriented boron nitride/silicon carbide scaffold for thermal-conductive and electrical-insulating phase change composites

Thermal energy harvesting, management and utilization with phase change materials have garnered increasing attention in integrated electronic cooling and high-power-density energy storage systems. However, intrinsic low thermal conductivity and melting leakage are two long-standing bottlenecks impeding their advanced thermal-related applications. Herein, we report a form-stable polyethylene glycol (PEG) composite based on the construction of lamellar-aligned and dopamine-modified boron nitride/silicon carbide aerogel (T-BSA) scaffold, which is fabricated by bidirectional freezing assembly followed by PEG vacuum-infiltration, consequently achieving vertically oriented heat-transfer pathways with low interfacial thermal barriers. The resultant T-BSA/PEG composite presented fascinating characteristics: a high through-plane thermal conductivity of 3.94 W m−1 K−1 and desirable latent heat of 132.1 J·g−1, together with superior leakage-proof ability, prominent thermal reliability and excellent electrical insulation. We demonstrated device integration with power LEDs and verified the superior cooling performance of T-BSA/PEG composite beyond commercial silicone rubber, by up to a 9.6 °C reduction in the hot spot temperature. Additionally, when integrated with a solar-driven thermoelectric generator, efficient solar-thermal-electric energy conversion was realized, with a peak output power density of 45.48 W m−2. This work raises applicative prospect of structurally designable and high-performance PEG composite in efficient thermal management of electronics and utilization of clean solar energy.