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

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 fibersbased 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. (C) 2019 Elsevier B.V. All rights reserved.