Although hydrophilic and electrically conductive transition-metal carbon/nitride (MXenes) nanosheets hold great promise for electrically conductive and electromagnetic interference (EMI) shielding applications, the weak interaction among MXene nanosheets makes them difficult to form compressible three-dimensional architectures with high conductivity. Herein, inspired by the plant "Parthenocissus tricuspidata", an efficient approach is demonstrated to fabricate conductive and lightweight Ti3C2Tx MXene/acidified carbon nanotube anisotropic aerogels (MCAs) with superelasticity and high thermal insulation. The MXene nanosheets construct the anisotropic and porous skeleton, while the acidified carbon nanotubes reinforce the pore walls of MXene nanosheets, making the MCAs superelastic and compressible. The superelastic MCA with only 5 wt % of the acidified carbon nanotubes is structurally stable during cyclic compressions at both high and ultralow temperatures. Its high conductivity (447.2 S m-1) and ultralow density (9.1 mg cm-3) endow its paraffin composite with a high EMI shielding efficiency of ∼51 dB at an ultralow filler content of 0.3 vol %. When the density of MCA increases to 18.2 mg cm-3, its EMI shielding effectiveness reaches 90 dB. Additionally, the porous and ultralight MCAs exhibit better thermal insulation performances as compared to commercial melamine and polystyrene foams. Therefore, the superelastic, electrically conductive, lightweight, and thermally insulating MCAs would be promising for EMI shielding applications in space equipment and portable wearable devices.
Keywords: MXene aerogels; compressibility; electrical conductivity; electromagnetic interference shielding; thermal insulation.