In situ-growth ultrathin hexagonal boron nitride /N-doped reduced graphene oxide composite aerogel for high performance of thermal insulation and electromagnetic wave absorption

Abstract

Owing to widely used various electronic devices in the rapidly developing 5G era, electromagnetic wave pollution could not be avoided. Security risks which caused by electromagnetic wave pollution have gotten serious attention. Especially in combat environment, applied electromagnetic wave absorption materials and reduced the surface temperature of combat equipment key parts would effectively reduce the risks of radar and infrared recognition. Herein, we designed hexagonal boron nitride (h-BN)/N-doped reduced graphene oxide (rGO) composite aerogels with 3D parallel porous network hetero-structure for electromagnetic wave absorption and thermal insulation. The results showed that attributed to structure design, dielectric loss and optimized impedance match, h-BN/rGO composite aerogels exhibited excellent electromagnetic wave absorption and thermal insulation performance. When the matching thickness was 3.1 mm, the effective absorption bandwidth was achieved up to 10.13 GHz in 7.9–18 GHz, and the minimum reflection loss was −21.49 dB. The TGA results exhibited that the thermal decomposition temperature of rGO was 560 °C, h-BN/rGO was 674 °C, which increased by 114 °C. Infrared imaging analysis showed that the surface temperature of 10 mm thick h-BN/rGO aerogel was only 44.45 °C in external thermal environment of 200 °C, which could effectively isolate the heat to 155.55 °C. The excellent electromagnetic wave absorption performance and effective heat isolation performance not only enabled the application of h-BN/rGO aerogel in the stealth materials, but also had application prospects in the thermal management field.