Towards multifunctional carbon composites: Rapid fabrication of hollow-skeleton and porous-skin composites derived from waste biomass

Carbonized materials are extensively utilized in various fields such as energy storage, catalysis, refractories and electronic devices due to their excellent conductivity, chemical stability and lightweight properties. However, conventional preparation methods are characterized by high energy consumption, time-consuming procedures and the necessity of complex atmospheres, which do not align with sustainable development goals. In this study, waste cotton fabrics and bamboo powder were employed as biomass carbon sources for the fabrication of carbon composites at 900 °C for 15 min under an air atmosphere with intumescent flame retardant (IFR) serving as a catalyst. The carbon composites exhibited a fully interconnected woven network structure, with the internal fibers possessing a hollow-skeleton architecture, while the outer layer consists of a continuous porous carbon. These hollow-skeleton and porous-skin carbon composites exhibits remarkable electrical conductivity and multiple reflective surfaces, which confer excellent electromagnetic interference (EMI) shielding performance. Consequently, their EMI SE T value could achieve an average EMI shielding performance of 36.98 dB. Moreover, the carbon composites could effectively transport electrons and absorbs photons, facilitating both electrical and luminous energy conversion processes. Specifically, IFR-C-B 20 could reaching 115 °C within 60 s under a low voltage of 2 V, and the water evaporation rate could reach 1.27 kg·m −2 ·h −1 . This work introduced a novel approach for the preparation of multifunctional carbon composites, significantly expanding their practical applications.