Hollow Graphene Fibers with Archimedean-Type Spirals for Flexible and Wearable Electronics

Graphene fiber (GF) processes attract prospects for flexible and wearable electronic applications by virtue of their excellent electrical conductivity, flexibility, strength, and being lightweight. Herein, we reported a facile method of fabricating hollow GFs with Archimedean-type spirals via a self-curing process induced from the counter-acting force of evaporation along a parabolic cross section. This strategy can boost the production rate up to 771.4 m h(-1) by printing the graphene oxide (GO) dispersion onto a rotating roller and then immersing in ethanol with the roller instead of injecting that into the coagulation bath directly, breaking through the rate limitation of the solidification in the conventional wet-spinning method. The 3D printing process on the rotating roller can not only transfer the ejecting dispersion continuously to form gel fiber but also provide a unilateral support to compress the fiber in the radial direction to a compacted layer structure during the solvent exchange process. Meanwhile, a series of such kinds of fibers with various diameters can be efficiently obtained by adjusting critical fabricating parameters of the injecting rate and the rotating rate. The as-fabricated pristine hollow GFs showed a reasonable tensile strength of 190.5 MPa with 6.1% elongation strain and good durability for bending over 5000 cycles. The demonstrative supercapacitor with the GF exhibited a high specific capacitance of 170.6 F g(-1). With the specific structure and reasonable performances, the hollow GFs hold great potential application to flexible and wearable electronics like stretchable circuitries, sensors, flexible batteries, and wearable supercapacitors.