Onion-like crystalline WS₂ nanoparticles anchored on graphene sheets as high-performance anode materials for lithium-ion batteries

In this study, onion-like crystalline WS₂ nanoparticles uniformly anchored on graphene sheets (WS₂@Gs) were prepared via ball milling using WO₃ nanoparticles and graphene and subsequent sulfidation. They were then employed as high-performance anode materials for Li-ion batteries (LIBs). The ball-milling process facilitated uniform anchoring of WO₃ nanoparticles with a diameter of ∼15 nm on graphene nanosheets without aggregation, and the subsequent sulfidation caused phase transition of the WO₃ nanoparticles to WS₂ nanoparticles with an onion-like crystal lattice structure. As anode materials for LIB, the uniquely structured WS₂@Gs nanocomposites exhibited excellent Li-ions storage performance, with a high reversible capacity of 587.1 mA h g⁻¹ at a current density of 200 mA g⁻¹. To enhance the cyclic stability of WS₂@Gs, the C-coating method was employed by simply adding glucose during ball milling. Even at a high current density of 1000 mA g⁻¹, the C-coated WS₂@Gs (C@WS₂@Gs) electrode exhibited a remarkably high reversible capacity of 371.9 mA h g⁻¹ and appreciable cycling stability, with a high capacity retention of 62% without any drastic capacity fading after 500 cycles.