Capacitive properties of carbon nanofibers derived from blends of cellulose acetate and polyacrylonitrile

Abstract

In this study, porous carbon nanofibers were produced via one-step carbonization and activation of cellulose acetate/polyacrylonitrile (CA/PAN) hybrid nanofibers using electrospinning. Zinc acetate effectively enhanced the thermal stability of CA without deacetylation and served as a template for pore creation. The effect of the mass ratio of CA to PAN on the microstructure and capacitive properties of the resulting carbon nanofiber membrane electrodes was investigated. All the membrane electrodes displayed self-supporting structures. The specific surface area, pore volume and specific capacitance of the membrane electrodes gradually increased with an increase in the CA : PAN mass ratio from 2 : 1 to 6 : 1, and then slightly decreased when the mass ratio reached 8 : 1. The CNF-C₆P₁ membrane electrode exhibited excellent flexibility, with a maximum specific surface area of ∼563.8 m² g⁻¹, largest specific capacitance of 132.2 F g⁻¹ at 0.5 A g⁻¹, and excellent rate capability of 53.3% at 20 A g⁻¹. After 4000 cycles of the charge/discharge process in a two-electrode system, this membrane electrode could still retain 85.1% of the original specific capacitance and the coulombic efficiency was close to 100%, showing high electrochemical stability and reversibility. This work provides a simple and effective strategy for the design and synthesis of flexible electrode materials for supercapacitors from cellulose acetate.