Resilient mesoporous TiO₂/graphene nanocomposite for high rate performance lithium-ion batteries

Mesoporous TiO₂/graphene composite is synthesized using graphene oxide (GO) and cheap TiOSO₄ as precursors via a facile one-step hydrothermal route. In this process, Ti(OH)₄, the hydrolysis product of TiOSO₄ in acidic environment reacts with functional groups (epoxy bridges, hydroxyl groups, carboxyl groups) on the GO sheets, which establishes strong Ti-O-C chemical bonds that link in situ formed TiO₂ nanoparticles and graphene sheets together. Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS) confirms the existence of the Ti-O-C chemical bond in the resultant composite. Such kind of chemical bond could prevent the aggregation of TiO₂ nanoparticles, avoid the restacking of graphene sheets, facilitate the fast transport of the Li-ions, enhance electronic conductivity, offer a high tap density, maintain the structural integrity during charge/discharge process, and consequently achieve excellent cycle stability and high rate capability in Li-ion batteries. At the current density of 5000mAg^-1, the discharge capacity of the composite can be readily retained at 141.7mAh g^-1 after 100 cycles, which is outstanding among the TiO₂ composites in the literature.