Si/C composite nanofibers with stable electric conductive network for use as durable lithium-ion battery anode

Abstract

High-energy anode materials have attracted significant attention because of their potential applications in large-scale energy storage devices. However, they often suffer from rapid capacity fading due to the pulverization of the electrode and the breakdown of electric conductive network caused by the large volume changes of active material upon repeated lithium insertion and extraction. In this work, a new electrode composed of Si/C composite nanofibers was prepared, aiming at the improvement of cycling performance of Si anodes through the establishment of a stable electric conductive network for Si during cycling. By electrospinning, a three-dimensional network of carbon nanofibers, which possesses good elasticity to maintain the structure integrity and stable electric conductive network, is formed; by carbon coating, all Si nanoparticles are tightly bonded with carbon fibers to form a stable electric conductive pathway for electrode reactions. The nanofiber structure and the carbon coating on Si, combined with the binder, lead to a stable network structure that can accommodate the huge volume change of Si during the repeated volume expansion and contraction, thus resulting in excellent cycling performance.