Isotropic thermal insulating cuttlebone-inspired MXene aerogel

Aerogels are considered to be 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 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 material inspired by the wall-septa microstructure of cuttlebone. The cuttlebone-inspired MXene aerogel (CMA) is fabricated through freeze casting colloidal suspensions composed of Ti₃C₂T <i>_x</i> 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 a rapid sensing response, robust fire resistance/fire warning, and excellent electromagnetic interference (EMI) shielding of ∼61 dB in both radial and axial directions. The structural integrity and EMI shielding performance remain stable over a wide temperature range (-196°C to 1300°C). This performance indicates the potential of CMA as a promising alternative to existing thermal insulation under extreme conditions.