Honeycomb-Structured MoSe2/rGO Composites as High-Performance Anode Materials for Sodium-Ion Batteries

Sodium-ion batteries are a promising substitute for lithium batteries due to the abundant resources and low cost of sodium. Herein, honeycomb-shaped MoSe 2 /reduced graphene oxide (rGO) composite materials are synthesized from graphene oxide (GO) and MoSe 2 through a one-step solvothermal process. Experiments show that the 3D honeycomb structure provides excellent electrolyte penetration while alleviating the volume change during electrochemical cycling. An anode prepared with MoSe 2 /rGO composites exhibits significantly improved sodium-ion storage properties, where a large reversible capacity of 215 mAh g −1 is obtained after 2700 cycles at the current density of 30.0 A g −1 or after 5900 cycles at 8.0 A g −1 . When such an anode is paired with Na 3 V 2 (PO 4 ) 3 to form a full cell, a reversible specific capacity of 107.5 mAh g −1 can be retained after 1000 cycles at the current of 1.0 A g −1 . Transmission electron microscopy, X-ray photoelectron spectroscopy and in situ X-ray diffraction (XRD) characterization reveal the reversible storage reaction of Na ions in the MoSe 2 /rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique honeycomb microstructure and the use of ether-based electrolytes. This study illustrates that combining rGO with ether-based electrolytes has tremendous potential in constructing high-performance sodium-ion batteries.