▎ 摘　　要

The sodium ion batteries have received great attention in recent years. However, the radius of sodium ion is larger than that of lithium ion, which results in the limited performance of sodium ion battery. In this work, to decrease the the diffusion time of sodium ions and improve the cyclic stability of sodium ion battery, the stack of manganese layered transition metal oxides and reduced graphene oxide (rGO) sheets has been fabricated as the cathode material. The layered MnO2@rGO composites were synthesized via the flocculation of the delaminated MnO2 nanosheets and rGO nanosheets with Na+ ions. By the synergistic effect of the two-dimensional MnO2 nanosheets and rGO, the sodium ion diffusion distance was decreased efficiently and abundant active sites were provided. By adopting the MnO2@rGO cathode, the sodium ion battery delivered specific capacity up to 167 mAh g(-1) at 0.5C, and exhibited excellent cycling stability (100 mAh g(-1)after 200 cycles). This work provides an efficient way to improve performance of sodium ion batteries.