One-Pot Spray-Dried Graphene Sheets-Encapsulated Nano-Li4Ti5O12 Microspheres for a Hybrid BatCap System

In this study, we report a facile strategy for constructing three-dimensional (3D) crumpled graphene sheets-wrapped nano-Li4Ti5O12 (LTO@GS) composites using a one-pot spray-drying assisted solid-phase reaction method with anatase TiO2 as a starting material. The proportion of graphene oxide (GO) in the LTO@GS composite greatly influences the phase formation and electrochemical performance of the composite. As an anode material for a nonaqueous, hybrid battery-capacitor (Bat Cap) system, the LTO@GS composite exhibits good high-rate capability and long cycle life. The specific capacitance still retains 90% of the initial value after 20 000 cycles, and the Coulombic efficiencies are close to 100%. This can reasonably be attributed to the interesting crumpled graphene-encapsulated structure and extraordinary synergistic effects between the two components.