In situ reduction of WS 2 nanosheets for WS 2 /reduced graphene oxide composite with superior Li-ion storage

Abstract Two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS 2 ), have been actively studied as suitable candidates for anode materials used in lithium ion batteries recently, due to their remarkable ion intercalation properties. However, the difficulties in the synthesis of phase-pure WS 2 , restacking between WS 2 nanosheets, low electronic conductivity and brittle nature of WS 2 severely limit its Li-ion batteries application. Here, we adopt a one-pot method for synthesizing of WS 2 /reduced Graphene Oxide (rGO) composite to improve the battery performance dramatically. The WS 2 /rGO anode shows a stable discharge capacity of 431.2 mAh/g, at a current density of 0.1 A/g after 100 cycles, while the capacity of bare WS 2 is only 65.5 mAh/g under the same condition. The added graphene oxide is reduced to rGO in reaction process and constitute stable composite with WS 2 , not only avoiding the restacking between WS 2 nanosheets and improving the conductive properties, but also promoting the reduction of WO 3 effectively. Our work may provide a possible route to avoid oxygen impurities in transition metal dichalcogenides.