Highly Strong and Conductive Carbon Fibers Originated from Bioinspired Lignin/Nanocellulose Precursors Obtained by Flow-Assisted Alignment and In Situ Interfacial Complexation
Lihong Geng, Yuhua Cai, Lu Li, Yaopeng Zhang, Yanxiang Li, Binyi Chen, Xiangfang Peng
Abstract
Composite filaments comprised of lignin and cellulose nanofibers (CNFs) were fabricated by a microfluidic spinning technique together with in situ interfacial complexation. The hierarchical assembly of well-ordered lignin/CNFs cross-linked using chitosan by ionic bonds resulted in the high orientation degree and compact microstructure of the filament, which was a promising precursor of carbon fibers. After stabilization and carbonization, bio-based carbon fibers with fine graphite microcrystals were obtained and carbon lattice was highly oriented along the fiber direction, contributing to the superior macro-performance. When the content of lignin was 75 wt %, the tensile strength and electrical conductivity of the carbon fibers reached 1648 MPa and 185.3 S/cm, respectively, surpassing the most reported values in the literature. Furthermore, a combined TG-FTIR approach was applied to further analyze the carbonization process of lignin/CNF precursors. The excellent mechanical and electrical performance of the bio-based carbon fibers would broaden their applications as a reinforcing agent and an electrical device. The demonstrated spinning technology also offered an avenue for the fabrication of high-performance filaments and carbon fibers.