Fabrication of polyacrylonitrile/lignin-based carbon nanofibers for high-power lithium ion battery anodes

Low-cost carbon nanofibers are fabricated from lignin, the second most abundant raw material in wood after cellulose and polyacrylonitrile mixture as a carbon precursor by electrospinning, followed by suitable heat treatments. As the lignin content in the precursor increases, the carbon nanofibers become thinner, as seen from scanning electron microscopy images. However, their carbon structure and electrochemical performance are found to be very similar, even though surface functional groups on carbon nanofibers are slightly different from each other. For example, in the initial charge (lithium insertion) and discharge (lithium deinsertion) process, the reversible specific capacities of the various carbon nanofibers come from different precursor ratios of lignin and polyacrylonitrile are similar. Even at a fast (7 min) charge and discharge condition, the carbon nanofibers prepared from the lignin-containing precursors show a discharge capacity of 150 mAh g^-1. The lignin-based carbon nanofibers thus show promise for use in high-power lithium ion battery anodes with low price.