MoS2/Graphene Nanosheets from Commercial Bulky MoS2 and Graphite as Anode Materials for High Rate Sodium-Ion Batteries

Tuning heterointerfaces between hybrid phases is a very promising strategy for designing advanced energy storage materials. Herein, a low-cost, high-yield, and scalable two-step approach is reported to prepare a new type of hybrid material containing MoS2/graphene nanosheets prepared from ball-milling and exfoliation of commercial bulky MoS2 and graphite. When tested as an anode material for a sodium-ion battery, the as-prepared MoS2/graphene nanosheets exhibit remarkably high rate capability (284 mA h g(-1) at 20 A g(-1) (approximate to 30C) and 201 mA h g(-1) at 50 A g(-1) (approximate to 75C)) and excellent cycling stability (capacity retention of 95% after 250 cycles at 0.3 A g(-1)). Detailed experimental measurements and density functional theory calculation reveal that the functional groups in 2D MoS2/graphene heterostructures can be well tuned. The impressive rate capacity of the as-prepared MoS2/graphene hybrids should be attributed to the heterostructures with a low degree of defects and residual oxygen containing groups in graphene, which subsequently improve the electronic conductivity of graphene and decrease the Na+ diffusion barrier at the MoS2/graphene interfaces in comparison with the acid treated one.