Molybdenum disulfide nanosheet embedded three-dimensional vertically aligned carbon nanotube arrays for extremely-excellent cycling stability lithium-ion anodes

Abstract

Molybdenum disulfide (MoS₂) nanosheets embedded in three-dimensional (3D) vertically aligned carbon nanotube arrays (VACNTs) have been fabricated via a simple nebulization-assisted hydrothermal method. The MoS₂/VACNTs possess a highly ordered and uniformly oriented 3D structure with MoS₂ nanosheets adhering strictly to the surface of VACNTs. When evaluated as lithium-ion anode materials, so-obtained MoS₂/VACNTs composites containing 52 wt% MoS₂ exhibit superb electrochemical performances, including high capacity (1078 mA h g⁻¹ at 100 mA g⁻¹ after 1st cycle), good rate capability (789 mA h g⁻¹ at 2000 mA g⁻¹ after 20 cycles), and extremely-excellent cycling stability, for the MoS₂/VACNTs electrode can still deliver a discharge capacity of 512 mA h g⁻¹ after 1000 cycles at 5000 mA g⁻¹, compared with pristine MoS₂ (negligible discharge capacity at the 70th cycle). Such high electrical properties can mainly be attributed to the unique well-directed pore-morphology which provides low-resistant shortest diffusion pathways upon the high-conductive VACNTs to accelerate ion/electron movement. Moreover, the elastic spare-space inside/outside VACNTs as a buffer factor effectively restrains large volumetric change from MoS₂ during the charge/discharge process. It can be determined that such a structure is attractive to achieve extremely-excellent cycling stability lithium-ion anodes.