Hollow graphene fibres of highly ordered structure via coaxial wet spinning with application to multi-functional flexible wearables

Hollow graphene fibres have a large specific surface area with hollow, thereby increasing electrode electrolyte interfacial contact and promoting electron transport, have a layers structure of sheath as well as improving the mechanical properties. In this study, a one-step coaxial wet spinning method was adopted in which the core spinning solution was the same as the solidification solution. The graphene oxide (GO) dope in the shell was subjected to two-way solidification inside and outside and formed a dense shell. At the time, the injection speed ratio core/shell caused the core layer to pull rapidly on the shell, and the spinning dope was washed by the coagulation solution. The two opposite forces exerted a tug-of-war effect on the curved graphene sheet to gradually straighten it. Finally, a novel hollow graphene fibre with a dense and highly ordered shell was formed. Hollow fibres with a shell thickness of approximately 0.8 μm have a volume resistance of 1.14 × 10 −2 Ω cm and a strength of 79.27 MPa, while non-hollow graphene fibres have a volume resistance of 2.69 × 10 −2 Ω cm and a strength of 28.03 MPa. The hollow fibre also exhibited very stable electrical resistance during lateral compression cycles, providing a basis for the development of innovative hollow fibres for use in wearable flexible devices.