Highly electrically conductive biomass-derived carbon fibers for permanent carbon sequestration

Carbon fiber derived from biomass is an excellent method for permanently sequestering carbon from the atmosphere because of the chemical inertness of carbon fiber and its versatile applications. However, many biomass-derived carbon fibers fall short in producing high electrical conductivities. Here, we demonstrate bamboo cellulose derived carbon with high electrical conductivity that can permanently sequester 0.85 t of carbon/ha of bamboo/year. To fabricate carbon fibers, bamboo cellulose macrofibers were extracted from bamboo via performic acid treatment and air-drying, followed by stabilization and carbonization to create conductive carbon fibers. The carbon fibers were sequentially Joule-heated to form graphitized carbon fiber at ∼2000 °C for 20–30 s. The resulting carbon fibers demonstrated very high alignment of nanofibrils with high electrical conductivity of 25,300 ± 6270 S/m, which is one of the higher values among reported biomass-derived carbon fibers. Furthermore, a hectare of bamboo can capture 17 t of carbon per year, and the obtained carbon fiber can permanently store 0.85 t of the captured carbon. Additionally, lignin from the delignification process could be processed into valuable products such as battery anodes, wound dressings, supercapacitors, and biobased epoxies. Compared to existing biomass-derived products, the fabrication method presented here is inexpensive and produces fibers with very high electrical conductivity, suggesting fibers could be used in low-cost, high quantity applications such as concrete or bridge sensors requiring electrical conductivity and thermoplastic or resin impregnation.