Synthesis of Size-Tunable Anatase TiO2 Nanospindles and Their Assembly into Anatase@Titanium Oxynitride/Titanium Nitride-Graphene Nanocomposites for Rechargeable Lithium Ion Batteries with High Cycling Performance

This paper embarks upon three levels of undertaking ranging from nanomaterials synthesis to assembly and functionalization. First, we have prepared size-tunable anatase TiO2 nanospindles via a hydrothermal process by using tubular titanates as self sacrificing precursors. Second, we have densely dispersed the TiO2 nanospindles onto functional graphene oxides (GO) via a spontaneous self assembly process. After annealing of the TiO2/GO hybrid nanocomposite in an NH3 gas flow, the TiO2 surface was effectively nitridated and the GO was reduced to graphene sheets (GS) in order to further fortify the electronic functionality of the nanocomposite. Third, the anatase@oxynitride/titanium nitride GS(TiO2@TiOxNy/TiN-GS) hybrid nanocomposite was studied as an anode material for lithium ion batteries (LIBS). showing excellent rate capability and cycling performance compared to the pure TiO2 nanospindles. Our systematic studies have revealed that the TiO2@TiOxNy/TiN-GS nanocomposite with graphene nanosheets covered with the TiO2@TiOxNy/TiN nanospindles on both sides provide a promising solutions to the problems of poor electron transport and severe aggregation of TiO2 nanoparticles by enhancing both electron transport through the conductive matrix and Li ion accessibility to the active material from the liquid electrolyte. More generally, the size-tunable TiO2 nanospindles with their unique (101) outer surface planes provide an archetype for the in depth investigation of their surface-specific and size dependent phsicochemical properties.