A graphene-like MoS2/graphene nanocomposite as a highperformance anode for lithium ion batteries

Abstract

In this article, we report on the preparation of a graphene-like MoS₂/graphene nanocomposite by hydrolysis of lithiated MoS₂ (LiMoS₂) and its application as the anode material for lithium ion batteries. When the mass ratio of graphene/LiMoS₂ is 15/100, the obtained composite (MoS₂/GNS-15) displays a flower-like architecture composed of exfoliated nanosheets. The structure analyses further demonstrate that graphene-like MoS₂ is supported on the surface of graphene nanosheets (GNS) and some of the interlayer spacings of MoS₂ are enlarged with the intercalation of graphene. The reversible capacity of the MoS₂/GNS-15 nanocomposite is ∼1400 mA h g⁻¹ in the initial cycle and remains 1351 mA h g⁻¹ after 200 cycles at 100 mA g⁻¹. Furthermore, the capacity can reach 591 mA h g⁻¹ even at a high current density of 1000 mA g⁻¹. The excellent electrochemical performance of MoS₂/GNS-15 is due to the synergetic effect between highly conductive GNS and graphene-like MoS₂. On one hand, the GNS matrix can offer two-dimensional conductive networks and effectively suppress the aggregation of layered MoS₂ during the lithiation/delithiation process. On the other hand, graphene-like MoS₂ with an enlarged gallery can ensure the flooding of the electrolyte, provide more active sites and lower the diffusion energy barrier of Li⁺ ions.