Electrically conductive yet thermally insulating SiC nanowire aerogels enabled by vertical graphene nanosheet arrays

To meet the multifunctional demands of integrated electronics, SiC nanowire (SiCNW) aerogels are attractive due to their lightweight nature, thermal stability, and three-dimensional network structure, yet their intrinsically low conductivity and poor surface activity limit their applications. Compositing with carbon can improve conductivity, yet balancing electrical conductivity and thermal insulation performance remains challenging. Herein, vertical graphene nanosheet arrays (VGNs) were in-situ fabricated to construct an ultra-light and flexible SiCNWs@VGNs core-shell aerogel integrating electromagnetic interference (EMI) shielding, supercapacitor performance and thermal insulation performance. VGNs transform single-point nanowire contacts into multi-point conductive connections, enhancing in-plane electrical conductivity while preserving low density and high specific surface area. This structure facilitates rapid electron/ion transport, resulting in an areal capacitance five times that of pristine SiCNWs aerogel. The abundant interfaces and defects of VGNs promote effective electromagnetic wave attenuation, exhibiting a high EMI shielding effectiveness of 41.50 dB at 1.5 mm, a specific shielding effectiveness of 2787.11 dB cm³ g⁻¹ and EMI shielding stability even after 2000 folding cycles. Importantly, the point-contact core-shell architecture and hierarchical pore structure ensure exceptional thermal insulation performance even when exposed to a 650 °C alcohol lamp and a 1300 °C spray gun. This work provides a new strategy for designing lightweight, flexible, conductive, yet thermally insulating materials for next-generation integrated electronic systems.