▎ 摘　　要

Given the rapid developments in modern electronics, there is an urgent need for polymer composites with excellent heat-dissipating capabilities to address the cooling problem of these devices. However, designing a highly thermally conductive polymer composite that can outperform metals and ceramics while also exhibiting high processability and low cost remains a challenge. Herein, inspired by the fibrous pathway of human nervous system, natural wood fibers (WFs) are used as the template and coated with graphene nanoplates (GNPs) via a simple electrostatic self-assembly approach. Subsequent hot-pressing process yields "core-sheath" microstructured fibers, wherein the GNPs are compactly contacted face to face and arranged along the surfaces of the fibrous WF "cores". This WF@G biocomposite consists of highly efficient 3D fibrous "tracks" for heat transmission, resulting in an extremely high thermal conductivity of 134 W (m K)(-1), which is at par with those of many metals. It also exhibits several other desirable properties and functionalities, including high mechanical strength and excellent flame resistance as well as remarkable electromagnetic shielding and Joule heating performances, which has significant potential for use as a functional thermal management material (TMM). Hence, this study describes a simple yet scalable manufacturing technique for the development of advanced metal-level biomass-based TMMs.