Facile heteroatom doping of biomass-derived carbon aerogels with hierarchically porous architecture and hybrid conductive network: Towards high electromagnetic interference shielding effectiveness and high absorption coefficient

In order to eliminate the secondary electromagnetic pollution, it is imperative to develop high-performance electromagnetic shielding materials with high-efficiency absorption coefficient. However, it remains a formidable challenge to simultaneously achieve high EMI shielding effectiveness (SE) and high absorption coefficient. Herein, a facile and environmentally strategy was proposed to fabricate heteroatom-doped carbon aerogels via graphene oxide nanosheet (GONS)/cellulose composite hydrogels as precursors for absorbing organic dyes, followed by freeze-drying and a specific two-stage carbonization process. The biomass-derived carbon aerogels possessed hierarchically porous architecture and heterogeneous conductive network with great conductivity difference. Consequently, the heteroatom-doped GNS-based carbon aerogels exhibited an outstanding EMI SE of 97.3 dB in the X band and high absorption coefficient of 0.69 at a density of as low as 68.9 mg/cm3. The highly efficient EMI shielding performance originated from the multiple shielding mechanisms involving multiple reflection, interfacial polarization, conduction loss and dipole polarization, which could effectively absorb and dissipate the incident EMWs as heat energy. The ingenious structural design puts forward a promising approach to conquering the contradiction between high EMI SE and high absorption coefficient, and the carbon aerogels have great potential or value in the applications of aircraft and spacecraft as lightweight shielding materials.