Ultralight elastic Al2O3 nanorod-graphene aerogel for pressure sensing and thermal superinsulation

Abstract

Novel nanorod aerogels have gained tremendous attention owing to their unique structure. However, the intrinsic brittleness of ceramics still severely limits their further functionalization and application. Here, based on the self-assembly between one-dimensional (1D) Al₂O₃ nanorods and two-dimensional (2D) graphene sheets, lamellar binary Al₂O₃ nanorod-graphene aerogels (ANGAs) were prepared by the bidirectional freeze-drying technique. Thanks to the synergistic effect of rigid Al₂O₃ nanorods and high specific extinction coefficient elastic graphene, the ANGAs not only exhibit robust structure and variable resistance under pressure, but also possess superior thermal insulation properties compared to pure Al₂O₃ nanorod aerogels. Therefore, a series of fascinating features such as ultra-low density (3.13–8.26 mg cm⁻³), enhanced compressive strength (6 times higher than graphene aerogel), excellent pressure sensing durability (500 cycles at 40% strain) and ultra-low thermal conductivity (0.0196 W m⁻¹ K⁻¹ at 25 °C and 0.0702 W m⁻¹ K⁻¹ at 1000 °C) are integrated in ANGAs. The present work provides fresh insight into the fabrication of ultralight thermal superinsulating aerogels and the functionalization of ceramic aerogels.