A Bioinspired Nanofibrous Titania/Silicon Composite as an Anode Material for Lithium-Ion Batteries

A hierarchical nanofibrous titania/silicon composite composed of anatase titania nanoparticles anchored as a thin coating layer on the surface of a silicon nanofiber was synthesized by employing natural cellulose substance (e.g., commercial laboratory filter paper) as a template. It was obtained through magnesiothermic reduction of the titania/silica replica of a cellulose substance prepared by a sol-gel process. When used as an anode material for lithium-ion batteries, it showed improved electrochemical performances that were superior to those of the bare silicon counterpart, and which improved with increasing titania content in the composites. For the composite with 54.3wt% titania and titania nanoparticles with sizes of about 12nm, it delivered a specific capacity of 498.9mAhg(-1) after 200 charge/discharge cycles at a current density of 200mAg(-1). The enhanced electrochemical performances of the composite are attributed to its unique network structure, as well as the buffering effect of the titania coating layer for huge volume changes to the silicon fiber during repeated lithiation and delithiation processes.