Capillarity-driven assembly of single-walled carbon nanotubes onto nickel wires for flexible wire-shaped supercapacitors

Abstract

The carbon nanomaterials have been incorporated into composite electrode for wire-shaped supercapacitors (WSSs) to promote development of wearable electronics. Coating of carbon nanomaterials directly onto functional fiber is a facile strategy to prepare wire-shaped electrodes. However, it is still a critical challenge to maximize the adhesion of the nanomaterials onto aimed substrate fiber, while still maintaining the high specific area of the nanomaterials. Herein, both carbon nanotubes (CNTs) and graphene were coated onto the surface of nickel wires via capillary effect driven process. It was discovered that the one dimensional morphology of the CNTs not only benefited the adhesion of CNTs on the relatively smooth surface of the nickel metal wire, but also strengthened the infiltration of the electrolyte among the CNTs. On the contrast, the restacking of graphene oxide (GO) sheets retarded the infiltration of the electrolyte, resulting in inferior capacitive performance. The prepared Ni-CNT electrodes showed excellent electrochemical double layer capacitive performance along with the mechanical robustness and high flexibility. The constructed all-solid flexible wire-shaped supercapacitors maintained a high specific capacitance of approximately 30 F/g after 3000 cycles when bent by 45 degree. Keywords: Nickel wires, Carbon nanotubes, Graphene oxide, Capillary effect, Wire-shaped supercapacitors