Controllable Synthesis of TiO2/Graphene Nanocomposites for Long Lifetime Lithium Storage: Nanoparticles vs. Nanolayers

Abstract This work reported controllable synthesis of TiO 2 /graphene nanocomposites with various morphologies by a one-pot one-step solvothermal method and tested their lithium storage performance. In the absence of glucose, TiO 2 nanolayers grafted graphene with low crystallinity were obtained. In the presence of glucose at a low content, TiO 2 /graphene was composed with well-dispersed nanoparticles and has high crystallinity of TiO 2 , while at a high content of glucose, TiO 2 /graphene was a mixture of hierarchical TiO 2 microspheres and graphene covered with amorphous carbon. As a result, these TiO 2 /graphene nanocomposites went through different mechanisms of lithium ions insertion/extraction due to their different particle sizes and crystal structures. Compared with the ultrathin layers and microspheres morphologies, TiO 2 nanoparticles/graphene demonstrated high reversible capacity (>260 mAh g −1 at 0.1C, C = 168 mA g −1 ), long-term cycling ability at 1C (1000 cycles, retention 83%) and superior rate capability from 0.1C to 10C, and still delivers a high capacity of 154 mAh g −1 after 1000 cycles even at 2C. The superiority of TiO 2 nanoparticles/graphene benefits from the combination of small particle size (