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

摘要

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 angstrom, 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.