Lithium Storage Performance of Hollow and Core/Shell TiO2 Microspheres Containing Carbon

TiO2 microspheres containing carbon have been synthesized viaa one-pot hydrothermal process using CTAB as the mesoporous template and nanoparticle stabilizer and Ti(SO4)2 and sucrose as titanium and carbon precursors, respectively. Through well designed calcinations, TiO2 microspheres with various amounts of carbon-residue, such as core/shell C@TiO2, hollow neat H–TiO2, and hollow C/TiO2 composites, are obtained. When these microspheres are used as anode materials for lithium ion batteries, the lithium storage performance is significantly influenced by the structure and carbon-residue. With a thin shell of TiO2 nanoparticles and carbon-residue, the capacity of hollow C/TiO2 composites maintains at 143.3 mA·h·g− 1 at 0.5 C (83.5 mA·g− 1) after 100 cycles. Moreover, after high rate charge/discharge cycles from 0.2 C to 20 C and back to 0.2 C again, the reversible capacity recovers atas high as 195.1 mA·h·g− 1 with respect to its initial value of 205.0 mA·h·g− 1. The results of cycle voltammograms and electrochemical impedance spectroscopy further reveal that Li+ insertion/extraction processes are reversible, and the diffusion coefficient of Li+ in the hollow C/TiO2 composites is much higher than those of others, because the hollow structure can act as the ion-buffering reservoir and facilitate Li+ transfer from both sides of the shell, and the carbon-residue in the shell improves the conductivity as well.

Graphical abstractTiO2 microspheres with various amounts of carbon-residue, such as core/shell C@TiO2, hollow neat H–TiO2, and hollow C/TiO2 composites have been obtained viaa one-pot hydrothermal process. With a thin shell of TiO2 nanoparticles and carbon-residues, the capacity of hollow C/TiO2 composites maintains at 143.3 mAh·g− 1 at 0.5 C (83.5 mA·g− 1) after 100 cycles.Figure optionsDownload full-size imageDownload as PowerPoint slide