Ultrathin MoS2/Nitrogen‐Doped Graphene Nanosheets with Highly Reversible Lithium Storage

Abstract

The extensive range of possibilities for using a rechargeable lithium ion battery (LIB) for stationary power storage applications has stimulated signifi cant research to improve its energy, power density and cycling life. The current use of graphite as a commercially available anode material cannot fully meet the energy density requirements for LIB applications in electric vehicles due to its relatively small capacity (372 mAh/g). In the next generation LIB, graphite should be replaced by alternative higher capacity materials and graphene based composite is one of the promising choices. The discovery of graphene has attracted wide-ranging interest due to its unique physical and chemical properties and potential for applications in electronic devices and sensors. [ 1–3 ] This has led to the development of a signifi cant number of graphene-based materials for use as LIB anodes and results have been generally promising due to high specifi c capacity and improvement of its cycling ability. In recent years, chemical substitutional doping has been used to enhance the properties of graphene—further improving its properties beyond just morphology and size control. This includes the use of sulfur, boron, and nitrogen doping, the latter of which is particularly effective in modulating the electronic properties of graphene. [ 4–6 ] Based on these results, we expect that nitrogen-doped (N-doped) graphene will be used as a template for synthesis of active electrode materials. Compared to graphene-based metal oxide materials, some graphene-based transition metal sulfi des possess consummate 2D-layered structures. The matched structure between transition metal sulfi des and graphene avoids the exfoliation of electrode materials and capacity fading during the charge/discharge process. [ 7–9 ] As a typical layered transition metal sulfi de, MoS 2 has a structure similar to graphite, consisting of three atom layers of S-Mo-S stacked together through van der Waals interactions. [ 10 , 11 ] This layered structure enables the effi cient intercalation and deintercalation of lithium ions. In recent years, many published reports have articulated various processes for preparing MoS 2 or MoS 2 composites as LIB anodes, which