A novel strategy for large-scale preparation of flexible high-conductivity carbon fiber paper for supercapacitors

Abstract

In order to solve the problems of high cost and high brittleness of commercial carbon fiber paper, a low-cost mass production method of carbon fiber paper for flexible super capacitor was proposed. The dispersant CMC-Na is utilized to achieve uniform dispersion of chopped carbon fiber in a water system through ultrasonic dispersion. Sheath-core composite (PE/PET) fiber not only enhances the tensile strength of CFP but also consolidates the electrode network structure formed based on carbon fiber structure. The CFP-3 electrode, impregnated with 3 % AC phenolic resin, exhibits excellent mechanical and electrochemical properties. SEM images reveal that AC is deposited on each carbon fiber and that the CFP-3 electrode retains its three-dimensional structure (with a porosity of 71.2 %), providing an effective permeation path for electrons (with an electrical conductivity of 0.871 S m−1). The CFP-3 electrode can restore its original shape after folding and bending without damage. Electrochemical tests demonstrate that the CFP-3 electrode has a high areal capacitance of 507.2 mF cm−2 at a current density of 0.5 mA cm−2. At a current density of 10 mA cm−2, the capacitance retention rate of the CFP-3 electrode is 96.1 % after 5000 charge-discharge cycles, owing to the well-interconnected structure of the carbon fiber paper. Furthermore, when used as a direct electrode, CFP exhibits excellent stability. Most notably, the cost of producing the CFP-3 electrode (0.0314 m2) is only $0.195, significantly lower than that of commercial products, excluding equipment, utilities, and labor costs. This research provides valuable insights for the low-cost, large-scale production of paper-based flexible supercapacitors.