Synergistic effects from graphene oxide nanosheets and TiO2 hierarchical structures enable robust and resilient electrodes for high-performance lithium-ion batteries

Abstract

We present a facile one-step route for successfully fabrication of a flowerlike rutile/anatase TiO₂ hierarchical structure decorated with graphene oxide (GO). The primary oriented TiO₂ nanorods, with diameter of 10–20 nm, were closely wrapped with GO nanosheets to build secondary hierarchical architecture with a size of 1.07 μm, resulting in a compact, mechanically robust and stable structure, which is completely different from the TiO₂ nanoparticle/graphene composite obtained by using graphene as precursor under the same conditions. When used as an anode materials for lithium-ion batteries (LIBs), it exhibited a high reversible capacity and long cycling stability with high discharge capacities of 211 mA h g⁻¹ at 1C over 500 cycles and 130 mA h g⁻¹ at 5C after 1000 cycles. To better understand what underlying factors lead this TiO₂@GO hierarchical structure to achieve its excellent electrochemical performance, we have synthesized a series of bare TiO₂ hierarchical structures with systematic phase evolution changing from rutile to rutile/anatase and anatase. The effect of crystal phase on the electrochemical performance is then discussed, and the anatase TiO₂ electrode exhibited the best electrochemical performance among the bare TiO₂ electrodes. However, the rutile/anatase TiO₂@GO hierarchical structure demonstrated much better performance than the anatase TiO₂ electrode, which is ascribed to the synergistic effects from the TiO₂ hierarchical structure and GO nanosheets. This study will further guide the fabrication of functional nanocomposites by applying the “two is better than one” strategy.