Melt Spinning of Low-Cost Activated Carbon Fiber with a Tunable Pore Structure for High-Performance Flexible Supercapacitors

Activated carbon fibers are emerging as one of the most promising electrode for flexible supercapacitors, as they are highly conductive, lightweight, and flexible. However, the high preparation cost and unreasonable pore structure limit their practical application in supercapacitors. Here, we developed a cost effective and green method to fabricate activated carbon fiber with a controllable porous structure by employing Kraft hardwood lignin extracted from black liquor of papermaking as raw material and nano-SiO2 as hard template. The introduction of nano-SiO2 can not only form mesoporous in the fiber but also improve the graphitization degree and hydrophilicity of the fiber. The fabricated fiber with large specific surface area, appropriate pore structure, high conductivity, and strength can act as a superior electrode for flexible supercapacitors in terms of high specific capacitance, high energy and power density, outstanding rate capability, as well as good mechanical stability.