Preparation of flexible and binder-free lignin-based carbon nanofiber electrode materials by electrospinning in aqueous system

Lignin, as a widely distributed, renewable and environmentally friendly source of carbon, could been utilized for carbon nanofibers to not only maximize the usage of resources, but also expand the energy-related opportunities. In this research, flexible lignin-based carbon nanofibers are prepared by electrospinning lignin nanofibers in a new green aqueous solution of lignin and polyvinyl alcohol (PVA), which is then characterized by physical and chemical characterizations. The results reveal that optimal carbonization temperature of 800 degree celsius shows great improvements on the structural properties of lignin-based carbon nanofibers, which can be applied as binder-free electric double layer capacitor (EDLC) electrodes with good flexibility. The 2032 type button battery has a superior electrochemical performance with a large specific capacitance of 217.2 F g(-1) at a 0.2 A g(-1) current density, and remarkable cyclic stability of 94.9 % capacitance retention even after 10,000 charge and discharge cycles, due to the abundance of mesoporous volume and large microporous surface area of lignin-based carbon nanofiber electrodes carbonized in 800 degree celsius.