Electrochemical Performance of Sandwich-like Structured TiO2/graphene Composite as Anode for Potassium-ion Batteries

The TiO 2 /graphene composite was synthesized by a simple hydrothermal reaction combined with a post high-temperature sintering in an inert atmosphere using graphene oxide (GO), butyl titanate and NaOH as raw materials. The TiO 2 /graphene composite is composed of mesoporous graphene nanosheets and dispersive TiO 2 nanoparticles that are attached to the surface and reside in the interlayer of graphene. Benefiting from the special microstructure and synergetic effects of electroactive materials TiO 2 and graphene, TiO 2 /graphene composite is superior in charge capacity, rate capability and cycle performance to both graphene and TiO 2 . As anode materials for potassium-ion batteries, TiO 2 /graphene, graphene and TiO 2 present initial charge capacities of 336.8, 261.9 and 30.3 mAh g -1 at 100 mA g -1 , respectively, and maintain 245, 135.5 and 18.5 mAh g -1 after 100 cycles, respectively. Even at a high current density of 600 mA g -1 , the remaining charge capacity of TiO 2 /graphene is 120 mAh g -1 after 100 cycles, significantly higher than those of graphene (50.7 mAh g -1 ) and TiO 2 (4.5 mAh g -1 ).