Design and fabrication of cellulose derived free-standing carbon nanofiber membranes for high performance supercapacitors

Free-standing N-doped carbon nanofiber membranes have been obtained from cellulose acetate (CA) and soy protein isolate (SPI). As an environmental friendliness, inexpensive and abundant polysaccharide in nature, cellulose and its derivatives have shown great potentials in the preparation of energy storage materials. This work successfully fabricated cellulose-based carbon nanofiber membranes through electrospinning, regeneration process and carbonization. Furthermore, this paper has intensively studied the electrospinning parameters of CA (main component) and SPI composite fiber membranes and explored the influence of carbonization temperature on their microstructure and electrochemical properties. The resultant CA-SPI derived carbon nanofiber membranes are applied in supercapacitors (SCs) for the first time, and display good electrochemical performance because of their unique structures and pseudo-capacitance contribution from heteroatoms. The asreceived CA-SPI-800 exhibits large specific capacitance of 219.3 F g(-1) at 0.2 A g(-1) in 6 M KOH. CA-SPI-800 shows high cycling stability with 98.9% capacitance retention after 50,000 cycles at 20 A g(-1). The symmetrical supercapacitor possesses 99% Columbic efficiency and outstanding cycling stability of 94.1% retention after 40,000 charging-discharging processes at 20 A g(-1). It is expected that the design of CA-SPI nanofiber membranes will provide a successful route for the preparation of cellulose derived nanofibers, and broaden their applications in low-consumption and green energy storage devices.