Porous Carbon Nanofiber Derived from a Waste Biomass as Anode Material in Lithium-Ion Batteries

In this study the entire process chain from raw biomass to carbon nanofiber (CNF) to high functioning lithium ion batteries (LIB) have been followed to evaluate the use of renewable materials for components of energy storage device. Electrospun CNF was prepared from a waste walnut shells using a relatively simple procedure for liquefying, electrospinning and carbonizing the fibrils. Mats of these CNF were used in LIB without binder, and the performance was measured as a function of the parameters used to prepare the nanofibers. Electrospinning solutions to polyvinyl alcohol at mass ratio of 80/20, 70/30 to 60/40 and carbonization temperature in the range from 800, 1000 to 1200 °C were used and the morphology, structure properties, and specific surface area of the walnut shell-derived carbon nanofiber (CNF) were comprehensively characterized. Their electrochemical performance were also investigated as electrode materials in LIB. The electrode obtained at 800 °C with mass ratio of 80/20 shows the highest specific capacity of 380 mA h g⁻¹ at 0.03 A g⁻¹ with an initial efficiency of 55.89%, and presents excellent cycling performance and high degree of reversibility (above 280 mA h g⁻¹ specific capacity after 200 cycles at 0.1 A g⁻¹).