Nonwoven fabrics

A novel electrode structure for Li-ion batteries was created by thermally treating nonwoven polyacrylonitrile (PAN) fabric in an inert atmosphere. Rapid carbonization of PAN fiber, stabilized in an inert atmosphere, produced a fused carbon fiber structure having a reversible specific capacity for lithium above 300 mAh/g; with charge reversibility between 95 and 100%. Chemical, structural and electrochemical analyses, including electrochemical impedance spectroscopy were performed on carbon fiber electrodes. Scanning electron microscopy revealed grooves and striations on the surfaces of carbon fibers prepared from PAN precursors stabilized in oxygen; but could not resolve any surface features on the fused carbon fibers, prepared from PAN precursors stabilized in an inert atmosphere. The fused, porous carbon fibers are believed to contain a large fraction of carbon chains with relatively few carbon planes.