TiO2nanocrystal embedded ordered mesoporous carbons as anode materials for lithium-ion batteries with highly reversible capacity and rate performance

Abstract

The ordered mesoporous carbon/TiO₂ (OMCT) nanocomposites with TiO₂ nanocrystals embedded within ordered mesoporous carbon (OMC) were prepared by a simple solvothermal method. The effect of TiO₂ nanoparticle incorporation in OMC matrix on the mesoporous structure, pore size, pore volume, surface area and microstructure of OMCT composites was investigated using X-ray diffraction, N₂ adsorption–desorption and Brunauer–Emmett–Teller method, scanning electron microscopy and transmission electron microscopy. The electrochemical lithium storage capacities of OMCT composites with different incorporated TiO₂ nanoparticles are comparatively investigated using cyclic voltammetry and galvanostatic charge–discharge techniques. It is suggested that the OMCT composites as anode materials for lithium ion batteries display a greatly improved electrochemical performance with high reversible capacity, coulombic efficiency, rate capability and cycling performance. As an anode electrode for Li-ion battery, OMCT₁₅ composite with an incorporated TiO₂ nanocrystal content possesses a high reversible capacity of 540.9 mA h g⁻¹ even up to 60 cycles at a high current density of 100 mA g⁻¹, with a stable coulombic efficiency of 98% and good rate capability. Especially at the current density of 1600 mA g⁻¹ after 50 cycles, the reversible capacity of the OMCT₁₅ remains at a value of 260 mA h g⁻¹, 5 times that of the OMC (48.9 mA h g⁻¹) and 21 times that of the pure TiO₂ (12.4 mA h g⁻¹) electrodes, respectively. The improved electrochemical lithium storage performance of high reversible capacity, coulombic efficiency, rate performance and cycling ability can be mainly attributed to the synergic effects between the TiO₂ nanoparticles and the three dimensional OMC matrices.