Long-Term\nCycling Studies on Electrospun Carbon Nanofibers\nas Anode Material for Lithium Ion Batteries

Abstract

Electrospun\ncarbon nanofibers (CNF) have been prepared at different\ncalcination temperatures for a prolonged time (12 h) derived from\nelectrospun polyacrylonitrile (PAN) membranes. They are studied as\nanode materials in lithium ion batteries due to their high reversible\ncapacity, improved long-term cycle performance, and good rate capacity.\nThe fibrous morphologies of fresh electrodes and tested samples for\nmore than 550 cycles have been compared; cyclic voltammogram (CV)\nhas also been studied to understand the lithium intercalation/deintercalation\nmechanism of 1D nanomaterials. CNFs demonstrate interesting galvanostatic\nperformance with fading capacity after the first few cycles, and the\ncapacity increases during long-term cycling. The increasing capacity\nis observed accompanied by volumetric expansion on the nanofibers’\nedge. Results of rate capacity have also been explored for all CNF\nsamples, and their stable electrochemical performances are further\nanalyzed by the galvanostatic intermittent titration technique (GITT)\nand electrochemical impedance spectroscopy (EIS). CNF carbonized at\n800 °C is found to have a larger lithium ion storage ability\nand better cyclic stability than that carbonized at 600 and 1000 °C.