Graphene/SiC nanowire heterointerfaces in wood-derived carbon scaffolds for integrated electromagnetic attenuation and phase-change thermal management

The progressive miniaturization and high power density of modern electronic devices have created an urgent demand for multifunctional materials that can simultaneously address electromagnetic interference (EMI) and thermal dissipation challenges. Herein, a wood-derived carbon (WDC) scaffold was sequentially modified with SiC nanowires (SiCnws) and graphene (GE) nanosheets via sol-gel/carbothermal reduction and chemical vapor deposition, followed by paraffin wax (PW) infiltration, to fabricate a multifunctional WDC-SiCnws-GE-PW phase change composite. The synergistic incorporation of SiCnws and GE constructed abundant heterointerfaces and a continuous conductive network within the hierarchically porous WDC skeleton. The WDC-SiCnws-GE absorber delivered a minimum reflection loss of −54 dB and an effective absorption bandwidth of 3.1 GHz at an ultrathin thickness of 2.1 mm. Cole-Cole analysis, together with microstructural and compositional evidence, suggested that the enhanced absorption performance is associated with a synergistic dielectric loss mechanism involving interfacial polarization at multiple heterointerfaces such as SiCnws-GE, WDC-GE, and WDC-SiCnws, dipole polarization from SiCnws stacking faults and GE edge functional groups, and conduction loss from the interconnected GE network. After PW infiltration, the resulting WDC-SiCnws-GE-PW composite exhibited outstanding thermal management performance, including a high axial thermal conductivity of 1.35 W/(m·K) (419% enhancement over WDC-PW), high melting and crystallization enthalpies (149.53 and 138.50 J/g), an energy storage efficiency of 99.35%, and rapid thermal response. This work provides a promising strategy for constructing lightweight, high-performance, multifunctional biomass-derived carbon-based composites for integrated EMW absorption and thermal management applications.