Multimode Thermal Gating Based on Elastic Ceramic-Carbon Nanowhisker/Nanofiber Aerogels by Strain Engineering Strategy.

Abstract

The capability to regulate heat transport dynamically and reversibly within solid materials propels advancement in aerospace conditioning, battery thermal control, and energy harvesting/conversion industries. Although aerogels are known for thermal insulation properties, their constant thermal resistance induced by immutable pore structure makes them struggle to reverse-release the accumulated thermal energy. Here, we develop a nanocrystalline whisker/nanofiber aerogel (WFA) thermal gating induced by the self-catalyzed growth strategy, whose elasticity offers possibilities for dynamic thermal management. Thermal conductivities can be continuously regulated by external compressive strain-trigged heat conduction pathway and interfacial resistance variations, switching seamlessly between 0.020 W m^-1 K^-1 in an uncompressed state and 0.071 W m^-1 K^-1 at 80% compressive strain, with a modulation ratio of ∼3.55. The integral inorganic nature ensures the thermal stability of WFAs over a large thermal gradient, from -196 °C deep cryogenic to 1500 °C ultrahigh temperature. The resulting multimode WFAs provide a feasible solution for thermal management in extreme environments.