Nanooctahedra Particles Assembled FeSe2Microspheres Embedded into Sulfur-Doped Reduced Graphene Oxide Sheets As a Promising Anode for Sodium Ion Batteries

Abstract

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.