Surface modified TiO2/reduced graphite oxide nanocomposite anodes for lithium ion batteries

Abstract

Anatase TiO2 nanoparticles with an average crystallite size of ~ 20 nm are synthesized through a sol-gel method. A composite anode for Li-ion batteries is prepared with the synthesized TiO2 nanoparticles and reduced graphite oxide (RGO) as the conductive carbon source. After the preparation of TiO2/RGO nanocomposite, a novel surface modification is carried out by the employment of H2O2 to enhance the overall electrochemical performance of nanocomposite anode (TiO2/RGO-P composite). The physical and chemical characterizations of the surface modified TiO2/RGO-P composites are performed with X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analyses. The electrochemical performance of TiO2/RGO-P composite electrodes is investigated via galvanostatic charge-discharge cycling tests in a potential window of 1.0-3.0 V. Compared to the plain TiO2/RGO composite anode, the TiO2/RGO-P composite anode has higher reversible capacities and better cycling performance due to the enhanced and stable formation of 3D channels of TiO2 nanoparticles with RGO stemming from the surface modification with H2O2. The TiO2/RGO-P composite anode delivers reversible discharge capacities around 291 mA h g(-1) at a rate of 100 mA g(-1), whereas the value stays at 214 and 143 mA h g(-1) for the plain TiO2/RGO composite and TiO2 nanoparticle without any RGO, respectively.