Preparation of hierarchical porous polyacrylonitrile-based fiber sponges and electrochemical performance study

Electrospinning is a simple and effective technique for preparing carbon nanofibers. However, carbon nanofiber materials have some drawbacks, such as low specific surface area, small pore size, and low porosity, which can affect the electrochemical performance of supercapacitors. This article proposes a preparation method for a multi-level porous structure for thick electrodes. Sponge-like nanofibers are formed through electrospinning by adding a certain amount of PMMA to the polyacrylonitrile mixed spinning solution after doping with heteroatoms. After reverse hanging pre-oxidation and carbonization, a hierarchical porous, highly conductive, and flexible carbon nanofiber sponge is obtained. After testing, at a current density of 0.25 A g-1, its specific capacitance reached 207 F g-1. As the power density increased from 250 W kg-1 to 3997.89 W kg-1, the energy density changed from 28.73 W h kg-1 to 8.44 W h kg-1, demonstrating that the porous active carbon nanofiber sponge electrode has a significant energy storage advantage.