Environmentally friendly a multifunctional cellulose-based carbon foam for superior electromagnetic wave absorption performance

Ingenious microstructure and suitable multicomponent are still challenging for designing lightweight, low-cost, and resource-renewable microwave absorption materials. Herein, environmentally friendly cellulose-based three-dimensional (3D) porous carbon foams were successfully prepared by freeze-drying and carbonization process. The pyrolysis process under gradient temperature could give rise to tunable electromagnetic (EM) parameters. The minimum reflection loss of carbon nanotubes/cellulose foam under 700°C is −55.4 dB (2.11 mm) at 9.27 GHz benefiting from the construction of double nano-interfaces so-called unique “1D-1D” combination, which can improve interface polarization and impedance matching. Furthermore, such carbon foam exhibits good thermal insulation and hydrophobicity , guaranteeing the stable and durable EM wave absorption application in the field of resist deformation, water or humid environments, and high-temperature attacks. The ultralow density and strong absorption of 3D-network carbonized cellulose-based aerogel with superior heat insulation ability and exceptional hydrophobicity were successfully prepared via freeze-drying and annealing process in the first time, which could be useful to applicate in the aerospace, stealth weapons, EM protection, etc. • The innovative double-nano effect of nanocellulose combined with CNT promotes the dielectric loss. • The optimal reflection loss of carbon foam reaches -55.4 dB at 2.11 mm . • This carbon foam exhibits excellent heat insulation and hydrophobic properties .