科研之友
微信
新浪微博
Facebook
分享链接
摘要
Molybdenum disulfide (MoS2) has received considerable interest for electrochemical energy storage and conversion. In this work, we demonstrate a material on synthesis of a unique hierarchical hollow structure by growing layered MoS2 nanosheets on assembled graphene nanotubes via a template-sacrificed approach (named as graphene@MoS2 nanotubes). As a proof of concept, the graphene@MoS2 nanotubes as the anode materials of lithium-ion batteries exhibit excellent cycling performance at 400 mA g(-1) up to 120 cycles without considerable capacity loss (830 mA h g(-1), with 96.5% capacity retention) and high rate behavior (502 mA h g(-1) at 2000 mA g(-1)), which is far beyond than that of the pure MoS2 nanosheets and even graphene@MoS2 nanosheets composites. Furthermore, combined with in-situ TEM lithiation experiments, we find a novel conversion reaction mechanism of MoS2 anodes that Li ions induce structural destruction in c-direction following a dynamic layer-by-layer dissociation with Mo/Li2S composites left, rather than well-known multistep reaction in bulk phase. The first-principles computations verify that the surfacial relaxation of Li2S to form an anti-fluorite structure on higher electric conductive LixMoS(2) surface is the primarily thermodynamic driving force for activating the above-mentioned reaction. These results are envisaged to be helpful for designing durable conversion-type MoS2 anodes by surface engineering, and the hierarchical tubular feature further points out a new protocol for graphene based hybrid anode for enhanced lithium-ion batteries.
- 出版日期2017-10
- 单位北京工业大学
