Lightweight, stiff and Heat-Resistant Bamboo-Derived carbon scaffolds with gradient aligned microchannels for highly efficient EMI shielding

Abstract

Advanced multifunctional electromagnetic interference (EMI) shielding materials with lightweight, stiff, heat-resistant and superb shielding performance features are highly desired to eliminate the increasingly serious EM pollution. Herein, a series of bamboo-derived carbon scaffolds with naturally optimized anisotropic, hierarchical gradient and aligned microchannels are successfully fabricated as shielding materials through pyrolysis. The 3-mm thick pyrolyzed bamboo charcoal exhibits an ultrahigh shielding effectiveness (SE) of 81.52 dB, which can be significantly improved to a superb level of 95.67 dB, with the SEA value accounting for 93.71%, by endowing the charcoal with a more porous structure and an extra magnetic loss. The specific SE reaches 1823–2676 dB cm2 g−1, and the normalized SE achieves 75.55 dB/mm, which is higher than those of other carbon scaffolds produced to date. Such excellent shielding performance is mainly attributed to the ingenious combination of dielectric loss, the natural hierarchical gradient structure, the anisotropic pore effect, and magnetic loss. More importantly, the bamboo-derived carbon scaffold features robust compressive strength (35.97 MPa), ultralow thermal conductivity (0.161 W m−1 K−1), and high thermal structural stability (500 °C in air). This study paves the way for the utilization of natural green bamboo-based porous carbon scaffolds as multifunctional high-performance shielding materials.