Silicon carbide coated carbon nanotube porous sponge with super Elasticity, low Density, high thermal Resistivity, and synergistically enhanced electromagnetic interference shielding performances

•Carbon nanotube@SiC composite sponge has low density, high thermal resistivity.•Heterojunction doping forms at the interface and changes the electrical property.•The composites show outstanding electron-magnetic shielding property (greater than75 dB).•The composites achieved super elasticity and long cyclic stability. Electromagnetic interference (EMI) shielding materials with high thermal resistivity, lightweight and flexibility have been intensively demanded to protect precision electronic instruments in various cutting-edge fields. Herein, using a low-temperature growth strategy, we successfully constructed a carbon nanotube (CNT) @ silicon carbide (SiC) coaxial 3D porous composite sponge with comprehensive outstanding performances, including low density of 15–32 mg·cm−3; super elasticity with high shape-recovery of 95 % at compression strain of 96 %; reversible compression-release stability with shape retention of 86 % and stress retention of 85 % after 1000 loading–unloading cycles; excellent thermal resistivity of over 1000 °C in Argon or 700 °C in Air; eye-catching EMI shielding performance with EMI shielding effectiveness of up to 75.7 ± 6 dB in X-band which, to the best of our knowledge, is the highest value for silicon carbide (SiC) based porous EMI shielding materials. Our results not only provide guidance for the further development of the next-generation EMI shielding materials under extreme conditions, but also cast a light to explore fundamental mechanisms behind porous EMI shielding materials.