Nanooctahedra Particles Assembled FeSe2 Microspheres Embedded into Sulfur-Doped Reduced Graphene Oxide Sheets As a Promising Anode for Sodium Ion Batteries

Presently, considerable attention has been paid to the Fe-based dichalcogenides as anode materials for sodium ion batteries (SIBs) due to their abundant resources, chemical stability, and high theoretical capacity. In this paper, we make nanooctahedra particles assembled FeSe2 microspheres embedded into sulfur-doped reduced graphene oxide sheets through a one-step hydrothermal reduction route, in which the reduction of graphene oxide, the doping of sulfur atoms, and the preparation of FeSe2/sulfur-doped reduced graphene oxide (FeSe2/SG) composites are realized at the same time. When serving as anodes for SIBs, the FeSe2/SG electrode can display superior electrochemical performances with a large reversible capacity of 447.5 mA h g–1 at 0.5 A g–1 and an excellent rate capability of 383.3 and 277.5 mA h g–1 at the current density of 2.0 and 5.0 A g–1, which could be attributed to the introduction of sulfur atoms into the reduced graphene oxide structure and the synergistic effect between microsphere-like FeSe2 particles and sulfur-doped reduced graphene oxide sheets.