Strong Coupling of MoS Nanosheets and Nitrogen-Doped Graphene for High-Performance Pseudocapacitance Lithium Storage.

Layered material MoS is widely applied as a promising anode for lithium-ion batteries (LIBs). Herein, a scalable and facile dopamine-assisted hydrothermal technique for the preparation of strongly coupled MoS nanosheets and nitrogen-doped graphene (MoS /N-G) composite is developed. In this composite, the interconnected MoS nanosheets are well wrapped onto the surface of graphene, forming a unique veil-like architecture. Experimental results indicate that dopamine plays multiple roles in the synthesis: a binding agent to anchor and uniformly disperse MoS nanosheets, a morphology promoter, and the precursor for in situ nitrogen doping during the self-polymerization process. Density functional theory calculations further reveal that a strong interaction exists at the interface of MoS nanosheets and nitrogen-doped graphene, which facilitates the charge transfer in the hybrid system. When used as the anode for LIBs, the resulting MoS /N-G composite electrode exhibits much higher and more stable Li-ion storage capacity (e.g., 1102 mAh g at 100 mA g ) than that of MoS /G electrode without employing the dopamine linker. Significantly, it is also identified that the thin MoS nanosheets display outstanding high-rate capability due to surface-dominated pseudocapacitance contribution.