Innovative N-doped graphene-coated WS2 nanosheets on graphene hollow spheres anode with double-sided protective structure for Li-Ion storage

Abstract

By skillfully designing the double-sided protective structure, WS2 nanosheets in situ grow on reduced graphene oxide hollow spheres (Hs-rGO). Then nitrogen doped graphene (NG) is coated on the outer layer to obtained NG@WS2@Hs-rGO. Double-sided protective structure of NG@WS2@Hs-rGO is successfully fabricated via a facile synthesis strategy. When evaluated as an anode material for Lithium-ion batteries (LIBs), NG@WS2@Hs-rGO exhibits a high specific capacity of 1309.4 mAh g−1 at 100 mA g−1 and excellent rate capability (166.1 mAh g−1 at a high current density of 4000 mA g−1). More strikingly, at a high current density of 1000 mA g−1, the NG@WS2@Hs-rGO electrode delivers a discharge capacity of 300.9 mAh g−1 after 320 cycles. The capacity retention of the electrode material reaches as high as 106% of the discharge capacity after the 10th cycle. Internally, the elastic Hs-rGO provides space for the bulk expansion of WS2. Externally, the outer layer of WS2 coated with NG not only improves the conductivity, but also provides more active sites for Li ion storage. The double-sided protective structure makes NG@WS2@Hs-rGO a potential anode material for light and high-performance LIBs.