Three-dimensional macroporous graphene monoliths with entrapped MoS2 nanoflakes from single-step synthesis for high-performance sodium-ion batteries.

ABSTRACT

Layered metal sulfides (MoS2, WS2, SnS2, and SnS) offer high potential as advanced anode materials in sodium ion batteries upon integration with highly-conductive graphene materials. However, in addition to being costly and time-consuming, existing strategies for synthesizing sulfides/graphene composites often involve complicated procedures. It is therefore essential to develop a simple yet scalable pathway to construct sulfide/graphene composites for practical applications. Here, we highlight a one-step, template-free, high-throughput "self-bubbling" method for producing MoS2/graphene composites, which is suitable for large-scale production of sulfide/graphene composites. The final product featured MoS2 nanoflakes distributed in three-dimensional macroporous monolithic graphene. Moreover, this unique MoS2/graphene composite achieved remarkable electrochemical performance when being applied to Na-ion battery anodes; namely, excellent cycling stability (474 mA h g-1 at 0.1 A g-1 after 100 cycles) and high rate capability (406 mA h g-1 at 0.25 A g-1 and 359 mA h g-1 at 0.5 A g-1). This self-bubbling approach should be applicable to delivering other graphene-based composites for emerging applications such as energy storage, catalysis, and sensing.