The chemical unzipping of directly-spun carbon nanotube fiber: Simultaneous enhancement of its mechanical and electrical properties as an efficient wearable supercapacitor

The hybridization of carbon nanotube (CNT) and graphene derivatives has been considered as one of the most promising approaches to develop a high-performance fiber-based energy storage with enhanced mechanical, electrical, electrochemical properties. Herein, we develop a simple and efficient unzipping strategy to directly convert CNT fiber (CNTF) into the nanohybrid fiber composed of CNTs and their unzipped counterparts with open edges presenting oxygen-containing functional groups. The unzipped CNTFs exhibit simultaneous enhancement of the wettability, mechanical, electrical, and electrochemical properties. The specific tensile strength, modulus, electrical conductivity, and specific capacitance of the pristine CNTFs are significantly enhanced by unzipping from 0.13 ± 0.01 N/tex, 2.75 ± 0.60 N/tex, 2780 ± 30 S/cm, and 7.62 F/g to 0.38 ± 0.01 N/tex, 8.71 ± 2.12 N/tex, 4440 ± 10 S/cm, and 67.54 F/g, respectively. Based on those improvements, they can be used as an electrical cable and supercapacitor to light a red light emitting diode (LED) bulb with serial connections. These results demonstrate the unzipping process is a significant strategy to fully harness the strong potential of CNTFs as a wearable energy storage device.