Wang Yinghui, Yang Ya, Zhang Deyang, Wang Yangbo, Luo Xiaoke, Liu Xianming, Kim Jang-Kyo, Luo Yongsong
Key Laboratory of Microelectronics and Energy of Henan Province, Henan Joint International Research Laboratory of New Energy Storage Technology, School of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, P. R. China.
School of Information Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China.
Nanoscale Horiz. 2020 Jun 29;5(7):1127-1135. doi: 10.1039/d0nh00152j.
As a two-dimensional layered material with a structure analogous to that of graphene, molybdenum disulfide (MoS2) holds great promise in sodium-ion batteries (SIBs). However, recent research findings have revealed some disadvantages in two-dimensional (2D) materials such as poor interlayer conductivity and structural instability, resulting in poor rate performance and short cycle life for SIBs. Herein, we designed MoS2 nanoflowers with an ultra-wide spacing interlayer (W-MoS2/C) anchored on special double carbon tubes to construct three-dimensional (3D) nanostructures. When tested as an anode material in a SIB, the as-prepared CNT@NCT@W-MoS2/C sample achieves high capacities (530 and 230 mA h g-1 at current densities of 0.1 and 2 A g-1, respectively). Density functional theory (DFT) calculations demonstrate that the ultra-wide spacing MoS2/C structure is beneficial for the chemical adsorption of sodium ions and facilitates redox reactions. The wide interlayer spacing and the presence of an intermediate carbon layer provide a rapid diffusion channel for ions and offer a free space for volume expansion of the electrode material.
作为一种结构与石墨烯类似的二维层状材料，二硫化钼（MoS2）在钠离子电池（SIBs）中具有巨大潜力。然而，最近的研究发现揭示了二维（2D）材料存在一些缺点，如层间导电性差和结构不稳定，导致SIBs的倍率性能不佳和循环寿命短。在此，我们设计了具有超宽层间距的二硫化钼纳米花（W-MoS2/C），其锚定在特殊的双碳管上以构建三维（3D）纳米结构。当作为SIBs的负极材料进行测试时，所制备的CNT@NCT@W-MoS2/C样品分别在0.1和2 A g-1的电流密度下实现了高容量（530和230 mA h g-1）。密度泛函理论（DFT）计算表明，超宽层间距的MoS2/C结构有利于钠离子的化学吸附并促进氧化还原反应。宽层间距和中间碳层的存在为离子提供了快速扩散通道，并为电极材料的体积膨胀提供了自由空间。
