Ultrathin sandwich-like MoS2@N-doped carbon nanosheets for anodes of lithium ion batteries

Abstract

In this work, we report on a simple and scalable process to synthesize the core-shell nanostructure of MoS2@N-doped carbon nanosheets (MoS2@C), in which polydopamine is coated on the MoS2 surface and is then carbonized. An intensive investigation using transmission electron microscopy and Raman spectroscopy reveals that the as-synthesized MoS2@C possesses a nanoscopic and ultrathin layer of MoS2 sheets with a thin and conformal coating of carbon layers (similar to 3 nm). The MoS2@C demonstrates a superior electrochemical performances as an anode material for lithium ion batteries compared to exfoliated MoS2 and bulk MoS2 samples. This unique core-shell structure is capable of delivering an excellent Li+ ion charging-discharging process as follows: a specific capacity as high as 1239 mA h g(-1), a high rate capability even at a high current rate of 10 A g(-1) while retaining 597 mA h g(-1), and a good cycle stability over 200 cycles at a high current rate of 2 A g(-1).