Hierarchical architecture of WS2 nanosheets on graphene frameworks with enhanced electrochemical properties for lithium storage and hydrogen evolution

Abstract

Hierarchical architecture of ultrathin interlayer-expanded WS₂ nanosheets supported on three-dimensional graphene (3DG) frameworks is fabricated by a facile hydrothermal method for the first time. The 3DG frameworks could provide large surface area for assembling WS₂ nanosheets and continuous pathways for rapid electron transfer and ion transport; and the WS₂ nanosheets with an expanded interlayer spacing of 9.58 Å, due to oxygen incorporation, could afford more space for lithium ion intercalation and more active sites for hydrogen evolution. The as-prepared WS₂/3DG composite exhibits a high capacity of 766 mA h g⁻¹ and excellent cycling stability for lithium storage, much better than its annealed counterpart and bulk WS₂. The hydrated sheet of WS₂/3DG also demonstrates boosted electrocatalytic activity for the hydrogen evolution reaction, possessing a low onset overpotential of 75 mV and an extremely large current density of 137 mA cm⁻² at 300 mV with remarkable durability. This work may open up a new pathway for improving the electrochemical properties by synergistically optimizing the electrode architectures and the intrinsic electroactivity of the active materials.