Biomimetic Biomass-Bsed Carbon Fibers: Effect of Covalent-Bnd Connection on Performance of Derived Carbon Fibers

Abstract

The morphological collapse of pure biomassbased carbon fibers is the main challenge restricting its development. Inspiration comes from nature that cellulose and lignin in natural trees are linked by covalent-bonds, leading to good extensibility and stability of wood. In this work, an effective strategy is presented to connect lignin and celluloseacetate by covalent-bond to obtain a novel carbon fiber precursor material. Isophorone diisocyanate was used as a chemical modifier to successfully connect lignin and celluloseacetate through a covalent-bond, which is formed by the urethane reaction of isocyanate group and hydroxyl group. With the introduction of covalent-bond connection, the precursor fibers exhibit a large molecular weight, uniform molecular weight distribution, excellent thermal stability, and good spinnability. After thermo-stabilization and carbonization, the pure biomass-based carbon fibers are successfully prepared. The results of SEM, BET, tensile test, and electrochemical properties test indicate that the covalent-bond connection effectively maintains morphology of fiber, which plays a key role for increasing the strength and the energy storage capacity of carbon fibers. The pure-biomass-based carbon fibers show promise for the production of high-quality, green, and cost reduced carbon fibers.

State of the Art and New Directions on Electrospun Lignin/Cellulose Nanofibers for Supercapacitor Application: A Systematic Literature Review

“…Filamentous and beads free nanofiber could mean that stable ECH influenced covalent bond formation between lignin and CA had successfully eliminated phase separation between lignin and CA molecular phases. A much similar approach to electrospinning covalently bonded lignin and CA into fine nanofibers was reported by Z. Dai et al [83]. In their report, isophorone diisocyanate (IPDI) was used to blend lignin and cellulose acetate.…”

“…However, electrospun lignin/cellulose nanofibers are not very successful due to morphological collapse of the resultant nanofibers due to phase separation. Phase separation between lignin and cellulose molecular phases are due to weak intermolecular interaction between lignin phenolic groups and cellulose hydroxyl groups [81][82][83]. Observed phase-separated nanofibers show two distinct phases: thermally stable but rigid lignin phase and mechanically flexible but thermally unstable cellulosic phase.…”

“…This supercapacitor recorded a high capacitance of 87 Fg −1 and a high energy density of 37 Whkg −1 . Alternatively, a homogenous slurry containing lignin/CA (active material), carbon black (conductive additive), and PTFE (binder) were coated onto nickel foam (current collector) to form the electrode [9,15,83].…”

“…Furthermore, lignin/cellulose nanofibers exhibit the thermal stability of lignin and flexibility of cellulose. The resultant carbon nanofiber maintains its fibrous morphology after carbonization [9,15,83]. Therefore lignin/cellulose nanofiber is a promising electrode material for supercapacitor applications.…”

Lignocellulosic Biomass-Derived Carbon Electrodes for Flexible Supercapacitors: An Overview

“…Studies of active materials for flexible/wearable energy storage devices based on these cellulose derivatives are still at an initial stage. For instance, isophorone diisocyanate (IPDI) was used as a chemical modifier to effectively connect lignin and cellulose acetate by covalent bond ( Figure 10 ) for better fiber spinnability [ 151 ]. The biomass-based carbon fibers had enhanced mechanical properties (maximum tensile strength of 49 MPa, Young’s modulus of 3 GPa), as well as good EC performance (later presented in Section 5.2 , Table 4 ).…”