Hydrothermal synthesis of mixed crystal phases TiO2–reduced graphene oxide nanocomposites with small particle size for lithium ion batteries

•Small particle sizes TiO2–RGO from 5 nm to 20 nm in diameter.•Fast charge/discharge rate and high enhanced cycling performance.•A green synthetic route to produce the small particle nanocomposite of TiO2–RGO.

A rutile and anatase mixed crystal phase of nano-rod TiO2 and TiO2–reduced graphene oxide (TiO2–RGO) nanocomposites with small particle size were prepared via a facile hydrothermal approach with titanium tetrabutoxide and graphene oxide as the precursor. Hydrolysis of titanium tetrabutoxide and mild reduction of graphene oxide were simultaneously carried out. Compared with traditional multistep methods, a novel green synthetic route to produce TiO2–RGO without toxic solvents or reducing agents was employed. TiO2–RGO as anode of lithium ion batteries was characterized by extensive measurements. The nanocomposites exhibited notable improvement in lithium ion insertion/extraction behavior compared with TiO2, indicating an initial irreversible capacity and a reversible capacity of 295.4 and 112.3 mA h g−1 for TiO2–RGO after 100 cycles at a high charge rate of 10 C. The enhanced electrochemical performance is attributed to increased conductivity in presence of reduced graphene oxide in TiO2–RGO, a rutile and anatase mixed crystal phase of nano-rod TiO2/GNS composites, small size of TiO2 particles in nanocomposites, and enlarged electrode–electrolyte contact area, leading to more electroactive sites in TiO2–RGO.