MoS₂ Nanosheets Vertically Grown on Graphene\nSheets for Lithium-Ion Battery Anodes

Abstract

A designed nanostructure with MoS₂ nanosheets (NSs)\nperpendicularly grown on graphene sheets (MoS₂/G) is achieved\nby a facile and scalable hydrothermal method, which involves adsorption\nof Mo₇O₂₄^6– on a graphene\noxide (GO) surface, due to the electrostatic attraction, followed\nby <i>in situ</i> growth of MoS₂. These results\ngive an explicit proof that the presence of oxygen-containing groups\nand pH of the solution are crucial factors enabling formation of a\nlamellar structure with MoS₂ NSs uniformly decorated on\ngraphene sheets. The direct coupling of edge Mo of MoS₂ with the oxygen from functional groups on GO (C–O–Mo\nbond) is proposed. The interfacial interaction of the C–O–Mo\nbonds can enhance electron transport rate and structural stability\nof the MoS₂/G electrode, which is beneficial for the improvement\nof rate performance and long cycle life. The graphene sheets improve\nthe electrical conductivity of the composite and, at the same time,\nact not only as a substrate to disperse active MoS₂ NSs\nhomogeneously but also as a buffer to accommodate the volume changes\nduring cycling. As an anode material for lithium-ion batteries, the\nmanufactured MoS₂/G electrode manifests a stable cycling\nperformance (1077 mAh g^–1 at 100 mA g^–1 after 150 cycles), excellent rate capability, and a long cycle life\n(907 mAh g^–1 at 1000 mA g^–1 after\n400 cycles).