Bundled Defect-Rich MoS2 for a High-Rate and Long-Life Sodium-Ion Battery: Achieving 3D Diffusion of Sodium Ion by Vacancies to Improve Kinetics

Kai Yao; Zhanwei Xu; Jianfeng Huang; Meng Ma; Licai Fu; Xuetao Shen; Jia Li; Maosen Fu

doi:10.1002/smll.201805405

Bundled Defect-Rich MoS₂ for a High-Rate and Long-Life Sodium-Ion Battery: Achieving 3D Diffusion of Sodium Ion by Vacancies to Improve Kinetics

Small. 2019 Mar;15(12):e1805405. doi: 10.1002/smll.201805405. Epub 2019 Feb 20.

Authors

Kai Yao¹, Zhanwei Xu¹, Jianfeng Huang¹, Meng Ma¹, Licai Fu², Xuetao Shen¹, Jia Li², Maosen Fu³

Affiliations

¹ School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an, 710021, China.
² College of Material Science and Engineering, Hunan University, Changsha, 410082, China.
³ Shaannxi Materials Analysis and Research Center, State Key Laboratory of Solidification Processing, School of Materials Science, Northwestern Polytechnical University, Xi'an, 710072, China.

PMID: 30786155
DOI: 10.1002/smll.201805405

Abstract

Molybdenum disulfide (MoS₂ ), a 2D-layered compound, is regarded as a promising anode for sodium-ion batteries (SIBs) due to its attractive theoretical capacity and low cost. The main challenges associated with MoS₂ are the low rate capability suffering from the sluggish kinetics of Na⁺ intercalation and the poor cycling stability owning to the stack of MoS₂ sheets. In this work, a unique architecture of bundled defect-rich MoS₂ (BD-MoS₂ ) that consists of MoS₂ with large vacancies bundled by ultrathin MoO₃ is achieved via a facile quenching process. When employed as anode for a SIB, the BD-MoS₂ electrode exhibits an ultrafast charge/discharge due to the pseudocapacitive-controlled Na⁺ storage mechanism in it. Further experimental and theoretical calculations show that Na⁺ is able to cross the MoS₂ layer by vacancies, not only limited to diffusion along the layer, thus realizing a 3D Na⁺ diffusion with faster kinetics. Meanwhile, the bundling architecture reduces the stack of sheets with a superior cycle life illustrating the highly reversible capacities of 350 and 272 mAh g^-1 at 2 and 5 A g^-1 after 1000 cycles.

Keywords: MoS2; defects; high rate; long life; sodium storage.

Abstract

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