Ultra-light MXene aerogel/wood-derived porous carbon composites with wall-like "mortar/brick" structures for electromagnetic interference shielding.

Renewable porous biochar and 2D MXene have attracted significant attention in high-end electromagnetic interference (EMI) shielding fields, due to unique orderly structures and excellent electrical conductivity (σ) value. In this work, the wood-derived porous carbon (WPC) skeleton from natural wood was performed as a template. And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites, based on highly ordered honeycomb cells inner WPC as a microreactor. Higher carbonization temperature is more conducive to the graphitization degree of natural wood. MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 dB at density as low as 0.197 g/cm. Such wall-like "mortar-brick" structures (WPC skeleton as "mortar" and MXene aerogel as "brick") not only effectively solve the unstable structure problem of MXene aerogel networks, but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy, thereby exhibiting the superior EMI shielding performance. In addition, MXene aerogel/WPC composites also exhibit good anisotropic compressive strength, excellent thermal insulation and flame retardant properties. Such ultra-light, green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry, etc.