Polymerized lignin based carbon nanofiber for high-performance energy generator and storage

• This work presents a simple and efficient strategy for optimizing lignin structure. • Lignin with different chemical structures can be prepared effectively by solvent fractionation. • This work has important reference value for developing high-quality lignin-based materials for the supercapacitors, sensors and moist-electric generators. Lignin is an ideal precursor for the preparation of lignin-based materials. However, the lack of molecular weight, thermal stability and spatial configuration of lignin hinder the practical application of lignin in lignin-based carbon materials. Herein, a novel and effective strategy for preparing high-performance lignin-based carbon nanofibers (CFs) is designed. Lignin samples with different chemical structures are prepared by polymerization modification and fractionation. This strategy completely gets rid of the dependence on petroleum-based polymers in the electrospinning process, and makes the lignin-based CFs show good performance in energy storage, temperature sensor, and moisture power generation. The specific capacitance and energy of lignin-based supercapacitors reach 357.2 F/g and 31.5 Wh/kg, respectively. The CFs exhibit good flame retardancy and thermal sensitivity, and the response time is 1 s. In addition, moisture power generators assembled with CFs exhibit great potential. The output voltage of moisture power generators has a linear relationship with the number of devices. With the increase of series equipment, the output voltage of 5 series moisture power generators is 4.7 V. This work provides a new approach to prepare high-performance lignin-based carbon nanofibers, which has a good application prospect in the fields of energy storage, sensing and power generation.