Biomass-Based Carbon Nanofibers Modified with Polyaniline for Supercapacitor Applications

The combination of biomass and functional polymers has always been an urgent challenge for the field of renewable energy storage materials. In this work, polyaniline-modified lignin is synthesized by in situ oxidation polymerization using lignin with different physical and chemical properties as a precursor raw material. The results imply that the physical and chemical properties of lignin significantly affect the degree and distribution of polyaniline polymerization, thus seriously affecting the conversion of lignin macromolecules and polyaniline segments during electrospinning and heat treatment. The obtained polyaniline-/biomass-based carbon nanofibers (CNFs) exhibit an excellent capacitance of 420 F/g at 1.0 A/g. Furthermore, the fabricated asymmetric supercapacitor delivers a high energy density of 29.4 W h/kg at a power density of 8 kW/kg in 1 M Na2SO4 with a good cycling stability (98.2% capacitance retention after 10,000 cycle numbers). In addition, biomass-based CNFs exhibit excellent flame retardant properties and fast thermal sensing properties (about 1.5 s). This work proposes the response relationship between chemical structure and chemical modification for the process of high-value utilization of lignin, which has important reference value for the development of high-quality biomass-based materials in supercapacitors.