Electrospun biomass based carbon nanofibers as high-performance supercapacitors.

• We first put forward the concept: a precursor fiber is a tree. It not only has good thermal stability of lignin, but also has flexibility of cellulose. • With the introduction of covalent-bond connection, the precursor fibers exhibit a large molecular weight, uniform molecular weight distribution, excellent thermal stability, and good spinnability. • The properties of resulting pure biomass-based carbon fibers are effectively improved by controlling the formation of covalent-bonds between lignin and cellulose-acetate. • The resulting pure biomass-based carbon fibers show independent filamentous morphology, uniform diameter, large surface area, excellent mechanical property and power storage capacity. • This work is a very valuable reference to the preparation of renewable and low-cost controllable fiber supercapacitor. The morphological collapse of pure biomass-based carbon nanofibers (CNFs) is due to the poor thermal stability of cellulose. Inspired by nature, cellulose and lignin are linked by covalent-bonds in trees made wood extensible and stable. In this work, an effective strategy was presented to mimic this biological structure for the preparation of biomass-based CNFs. Epichlorohydrin (ECH) is used to form the covalent-bonds between lignin and cellulose-acetate (CA) for a novel precursor material. With the introduction of covalent-bonds, precursor materials not only exhibit the spinnability of cellulose, but also possess the thermal stability of lignin. After carbonization, the pure biomass-based CNFs are successfully prepared and exhibit independent filamentous morphology, uniform diameter, large surface area, and power storage capacity. The specific capacitance of 320.3 F/g is obtained by using the CNFs-6 (prepared with 10 % ECH content) as super-capacitor. Simultaneously, the biomass-based CNFs super-capacitor device delivers a high energy density of 30.2 Wh/ kg at the power density of 400 W/kg. These results indicate that the introduction of covalent-bonds can effectively increase the energy storage properties significantly. This novel strategy showed a successful route for the preparation of high quality and low cost biomass-based CNFs. [ABSTRACT FROM AUTHOR]