Facile synthesis of MoS2/graphene composites: effects of different cationic surfactants on microstructures and electrochemical properties of reversible lithium storage
MoS2/graphene composites were synthesized through the concurrent reducing of (NH4)2MoS4 and graphene oxide sheets with assistance of different cationic surfactants (DTAB, OTAB and TBAB) followed by heat treatment in a nitrogen atmosphere. The effects of the three cationic surfactants on the microstructures and electrochemical performances of the composites for reversible lithium storage were investigated. The MoS2 in the composites prepared with assistance of DTAB or OTAB displays single-/few-layer structure, while the layered MoS2 sheets with about 6–7 layers are observed in the composite prepared with assistance of TBAB. The former two composites exhibit greatly enhanced electrochemical performance for reversible Li+ storage. In particular, MoS2/graphene composite prepared with assistance of OTAB delivered a high reversible capacity of 1056 mA h g−1 with excellent cycle stability and good rate capability. The significant improvement in the electrochemical performances is attributed to the roubest composite structure and the synergistic interactions between graphene and single-/few-layer MoS2. This work also presented a facile process to prepare MoS2/graphene composites, in which the layer number of MoS2 sheets could be adjusted to a certain extent by using different cationic surfactants.