Isotropic thermal insulating cuttlebone-inspired MXene aerogel

Abstract Aerogels are considered as ideal thermal insulation materials due to their low thermal conductivity and highly porous structure, which can effectively reduce the energy consumption in aerospace, industry, and building applications. However, the anisotropic performance of most aerogels results in high thermal conductivity in the axial direction, and the structures tend to collapse under the extreme temperature shock, leading to poor mechanical stability. Herein, we demonstrate a remarkable lightweight and isotropic thermal insulation aerogel materials inspired by the wall–septa microstructure of cuttlebone. The cuttlebone-inspired MXene aerogel (CMA) is fabricated through freeze casting colloidal suspensions composed of Ti3C2Tx MXene nanosheets, montmorillonite nanosheets, cellulose nanofibers and polyvinyl alcohol. The CMA shows an ultralow thermal conductivity of 17.1 mW m−1 K−1 in the radial direction and 19.7 mW m−1 K−1 in the axial direction. Additionally, the CMA also exhibits rapid sensing response, robust fire resistance/fire waring, and excellent electromagnetic interference (EMI) shielding of approximately 61 dB in both radial and axial directions. The structural integrity and EMI shielding performance remain stable from over a wide temperature range (-196ºC to 1300ºC). The performance indicates the potential of CMA as a promising attractive to existing thermal insulation under the extreme conditions.