Hierarchical MoS<sub>2</sub> Hollow Architectures with Abundant Mo Vacancies for Efficient Sodium Storage.

Li, Yang; Zhang, Rupeng; Zhou, Wei; Wu, Xin; Zhang, Huabin; Zhang, Jian · ACS Nano · 2019

basic_science · Level V

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Abstract

Achieving a molecular level understanding of surface performance of nanomaterials by modulating the electronic structure is important but challenging. Here, we have developed a hollow microcube framework constructed by Mo-defect-rich ultrathin MoS<sub>2</sub> nanosheets (HMF-MoS<sub>2</sub>) through a zeolite-like-framework-engaged strategy. The hollow structured HMF-MoS<sub>2</sub> delivers an impressive specific capacity (384.3 mA h g<sup>-1</sup> after 100 cycles at 100 mA g<sup>-1</sup>) and cycle stability (267 mA h g<sup>-1</sup> after 125 cycles at 1 A g<sup>-1</sup>) for sodium storage. As evidenced by experiments and density functional theory calculations, abundant Mo vacancies in MoS<sub>2</sub> can greatly accelerate the charge transfer and enhance the interaction between MoS<sub>2</sub> and sodium, resulting in the promotion of sodium storage. Kinetic analysis result reveals that the ultrafast sodium ion storage of HMF-MoS<sub>2</sub> could be associated with the significant contribution of capacitive energy storage. This work highlights the detailed molecular level understanding of chemical reaction on MoS<sub>2</sub> surface by defect and morphology engineering, which can be applied to other metal sulfides for energy storage devices.