Aramid Nanofibers Aerogel‐filled Wood‐based Carbon Material for Flexible Solid Supercapacitors

Abstract Delignified wood‐based carbon material is a potential cost‐effective and environmentally‐friendly flexible electrode material. However, the abundant intertubular cavities not only endow excellent flexibility, but also inevitably deteriorate the conductivity, integrity and areal density of the delignified wood‐based flexible carbon material, which is not conducive to improve the energy storage performance. In this work, an aramid nanofiber‐based carbon aerogel was filled in the intertubular cavities via a series of processes, including filled by virtue of the unidirectional capillary forces, gelation, freeze‐drying and carbonization. The filled carbon aerogel can significantly increase the conductivity and the sheet resistance is as low as about 28±5 Ω sq⁻¹. The filled carbon aerogel does not deteriorate its excellent energy storage behavior derived from the unique low‐tortuosity and open slender tubular microstructure. The filled carbon aerogel can improve the space utilization of the delignified wood‐based carbon. The areal specific capacitance has been increased from 20.8 to 51.9 mF cm⁻² at a current density of 50 μA cm⁻². The area specific capacitance still remains at 33.9 mF cm⁻² when the current density increased to 1000 μA cm⁻². The aramid nanofibers aerogel‐filled wood‐based carbon flexible interdigitated solid supercapacitors also exhibit excellent flexibility and folding endurance.