Scalable synthesis of TiO_2/graphene nanostructured composite with high-rate performance for lithium ion batteries

摘要

A simple and scalable method is developed to synthesize TiO_2/graphene nanostructured composites as high-performance anode materials for Li-ion batteries using hydroxyl titanium oxalate (HTO) as the intermediate for TiO_2. With assistance of a surfactant, amorphous HTO can condense as a flower-like nanostructure on graphene oxide (GO) sheets. By calcination, the HTO/GO nanocomposite can be converted to TiO_2/graphene nanocomposite with well preserved flower-like nanostructure. In the composite, TiO_2 nanoparticles with an ultrasmall size of several nanometers construct the porous flower-like nanostructure which strongly attached onto conductive graphene nanosheets. The TiO_2/graphene nanocomposite is able to deliver a capacity of 230 mA h g~(-1) at 0.1 C (corresponding to a current density of 17 mA g~(-1)), and demonstrates superior high-rate charge-discharge capability and cycling stability at charge/discharge rates up to 50 C in a half cell configuration. Full cell measurement using the TiO_2/graphene as the anode material and spinel LiMnO_2 as the cathode material exhibit good high-rate performance and cycling stability, indicating that the TiO_2/graphene nanocomposite has a practical application potential in advanced Li-ion batteries.