Graphene-supported TiO2 nanospheres as a high-capacity and long-cycle life anode for sodium ion batteries

Abstract

Anatase TiO₂ has low-cost and potentially high capacity as a Na-storage anode, but its low capacity utilization and poor rate capability remain a challenge for practical battery applications. To address this issue, we synthesized graphene-supported TiO₂ nanospheres through a facile hydrothermal process, aiming at enhancing the electrochemical capacity and kinetics of this material. The porous TiO₂ nanospheres offer abundant electrochemically active surface sites and ionic channels, enabling high utilization of the TiO₂ nanoparticles, meanwhile the rGO matrices provide high electronic conduction and prevent the aggregation of the TiO₂ nanoparticles during repeated cycles. The as-prepared rGO–TiO₂ electrode demonstrates a high capacity of 300 mA h g⁻¹ and a cycling stability with a capacity retention of 208 mA h g⁻¹ over 300 cycles. Also, this rGO–TiO₂ electrode exhibits a high rate capability of 123.1 mA h g⁻¹ at a very high rate of 4.0 A g⁻¹. The structural design and synthesis route described in this work may provide an effective approach to promote the electrochemical performance of Na-insertion materials for high-rate and high capacity Na-ion batteries.