Sulfiphilic Few-Layered MoSe2 Nanoflakes Decorated rGO as a Highly Efficient Sulfur Host for Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSBs) have been regarded as a competitive candidate for next-generation electrochemical energy-storage technologies due to their merits in energy density. The sluggish redox kinetics of the electrochemistry and the high solubility of polysulfides during cycling result in insufficient sulfur utilization, severe polarization, and poor cyclic stability. Herein, sulfiphilic few-layered MoSe2 nanoflakes decorated rGO (MoSe2@rGO) hybrid has been synthesized through a facile hydrothermal method and for the first time, is used as a conceptually new-style sulfur host for LSBs. Specifically, MoSe2@rGO not only strongly interacts with polysulfides but also dynamically strengthens polysulfide redox reactions. The polarization problem is effectively alleviated by relying on the sulfiphilic MoSe2. Moreover, MoSe2@rGO is demonstrated to be beneficial for the fast nucleation and uniform deposition of Li2S, contributing to the high discharge capacity and good cyclic stability. A high initial capacity of 1608 mAh g(-1) at 0.1 C, a slow decay rate of 0.042% per loop at 0.25 C, and a high reversible capacity of 870 mAh g(-1) with areal sulfur loading of 4.2 mg cm(-2) at 0.3 C are obtained. The concept of introducing sulfiphilic transition-metal selenides into the LSBs system can stimulate engineering of novel architectures with enhanced properties for various energy-storage devices.