Silk fibroin reinforced graphene fibers with outstanding electrical conductivity and mechanical strength

High-performance graphene fiber with intriguing functionality and mechanical strength is expected for wide potential applications. However, it still demands reliable means to realize the rapid wet-spinning of highly aligned fibers because of the insufficient gel strength of graphene oxide (GO) dope and the possible structural imperfections in the obtained fibers. Here, we demonstrate the fabrication of highly conductive and strong graphene fibers by regulating the rheology and spinnability of trace-carbonyl GO dispersion with silk fibroin (SF). The amphiphilic SF can form hydrogen bonds and π-π interactions with GO sheets to significantly enhance the gel strength of spinning dopes, enabling the conformation adjustment and sheet alignment under large drawing ratio and performance enhancement of the GO/SF fibers. After a chemical reduction, the highly orientated and stacked structure endows the fibers with an exceptional tensile strength of 938.6 MPa and a high electrical conductivity of 1501.7 S cm−1. Even more, the conductivity can be further increased to 2700.7 S cm−1, which is among the highest values for chemically reduced GO fibers. This work offers a promising method to produce strong, flexible, and robust graphene fibers for versatile applications in multifunctional fabrics, energy conversion, and health protection areas.