Large-scale preparation of thermally conductive graphene fiber filaments

Graphene fiber has emerged as a promising carbonaceous fiber with excellent integrated properties. Previous laboratory researches have focused on the prototype single fiber, but the scalable fabrication of graphene fiber filaments still remains nearly unexplored. Here, we report the large-scale industrial fabrication of graphene fiber filaments with high strength and superior thermal conductivity. During scalable wet -spinning process, we introduce step -wise solvent intercalation plastic stretching to improve the uniformity, density and structural order of precursor graphene oxide fiber filaments. The chemical reduction and high -temperature graphitization restore graphene atomic structure and achieve large graphitic crystallite sizes of filaments. The graphene fiber filaments demonstrate favorable overall performances, including tensile strength of 1.4 GPa, density of 1.93 g/ cm3, electrical conductivity of 4.1 x 105 S/m, and thermal conductivity of 1204 W/mK. The fabrication of graphene fiber filaments lays a foundation of their wide applications as textiles and composites and the solvent intercalation plastic stretching could be a general method to fabricate high performance fiber filaments of twodimensional materials.