Graphene\nFibers Containing Activated Graphene for\nHigh-Performance Solid-State Flexible Supercapacitors

Abstract

Fiber\nsupercapacitors (FSCs) can be used to power future flexible\ndevices such as wearable electronics and smart textiles. Here, highly\nporous activated graphene (AG) is embedded into graphene fibers to\nenhance the electrochemical performance of FSCs based on electric\ndouble-layer capacitance (EDLC). Wet spinning of AG mixed with graphene\noxide (GO) and subsequent chemical reduction of GO to reduced graphene\noxide (rGO) enable the fabrication of continuous and conductive graphene\nfibers. The AG powders with an extremely high surface area significantly\nimprove the electrochemical performance of the FSCs. In particular,\nthe rGO/AG fiber with an rGO/AG mass ratio of 80/20 achieves a specific\nareal capacitance of 145.1 mF/cm² at a current density\nof 0.8 mA/cm² with a PVA/LiCl gel electrolyte. This corresponds\nto areal energy and power densities of 5.04 μWh/cm² and 0.50 mW/cm² for the FSCs, respectively. Furthermore,\nflexible FSCs using the rGO/AG fibers demonstrate decent cycling capability,\nwith a capacitance retention of 91.5% after 10 000 cycles.\nThis work shows significant potential in fabricating AG-based fibers\nfor developing high-performance flexible FSCs.