Tuning the microstructure and electrochemical behavior of lignin-based ultrafine carbon fibers via hydrogen-bonding interaction

Abstract

Hardwood Kraft lignin (HKL)-based ultrafine carbon fibers with different pore structures and properties were prepared by controlling the intermolecular interaction between HKL and incorporated poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG) triblock copolymer. The thermal properties of HKL-based ultrafine fibers together with the morphology and pore structures of HKL-based ultrafine carbon fibers were extensively investigated with DSC, TG, SEM, BET, DLS and HRTEM to provide comprehensive knowledge on the effect of added PEG-PPG-PEG on the properties of obtained fibers. Results suggested that addition of PEG-PPG-PEG increased the thermal stability of HKL and promoted the formation of graphite crystallites in HKL-based ultrafine carbon fibers via enhanced intermolecular hydrogen bonding interactions. The electrochemical behavior of HKL-based ultrafine carbon fibers with different PEG-PPG-PEG contents were also characterized to expand their potential application in electrochemical capacitors. All the HKL ultrafine carbon fibers-based electrodes showed good capacitive behavior and stability. Besides, the specific capacitance of HKL-based ultrafine carbon fibers can be significantly tuned by the addition of PEG-PPG-PEG.