Hierarchical composites of ultrathin carbon self-coated TiO2 nanosheets on reduced graphene oxide with enhanced lithium storage capability

Novel carbon self-coated titanium dioxide nanosheets/reduced graphene oxide (TiO2@C/RGO) composites are successfully prepared via a facile one-pot solvothermal process, followed by calcination under an Ar/H-2 atmosphere. Ultrathin TiO2 nanosheets with average thickness of less than 10 nm are homogeneously anchored on surface of reduced graphene oxide nanosheets to form a hierarchical nanostructure, which can provide numerous open channels for the access of electrolyte and facilitate the fast diffusion of lithium ions during the cycling process. The morphological evolution process of the hierarchical structure has been detailedly investigated by sampling at different time intervals, and a possible mechanism has been proposed. When used as an active anode material for lithium ion batteries, the TiO2@C/RGO composites exhibited larger reversible Li-ion storage capacity with excellent cycling stability (401 mA h g(-1) after 200 cycles at a current density of 100 mA g(-1)) and better rate capability (126.5 mA h g(-1) at a current density of 2500 mA g(-1)) compared with those of the pure TiO2 and TiO2@C samples. The approach for the preparation of the hierarchical composite in this study may guide the way for designing new composite materials for enhanced lithium storage capability. (C) 2015 Elsevier B.V. All rights reserved.