Chemically Bonded TiO₂–Bronze Nanosheet/Reduced Graphene Oxide Hybrid for High-Power Lithium Ion Batteries

Although Li-ion batteries have attracted significant interest due to their higher energy density, lack of high rate performance electrode materials and intrinsic safety issues challenge their commercial applications. Herein, we demonstrate a simple photocatalytic reduction method that simultaneously reduces graphene oxide (GO) and anchors (010)-faceted mesoporous bronze-phase titania (TiO₂–B) nanosheets to reduced graphene oxide (RGO) through Ti³⁺–C bonds. Formation of Ti³⁺–C bonds during the photocatalytic reduction process was identified using electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) techniques. When cycled between 1–3 V (vs Li^+/0), these chemically bonded TiO₂–B/RGO hybrid nanostructures show significantly higher Li-ion storage capacities and rate capability compared to bare TiO₂–B nanosheets and a physically mixed TiO₂–B/RGO composite. In addition, 80% of the initial specific (gravimetric) capacity was retained even after 1000 charge–discharge cycles at a high rate of 40C. The improved electrochemical performance of TiO₂–B/RGO nanoarchitectures is attributed to the presence of exposed (010) facets, mesoporosity, and efficient interfacial charge transfer between RGO monolayers and TiO₂–B nanosheets.