Li Jianbo, Xu Yifan, He Yanan, Zhang Zhuangzhuang, Zhu Chuannan, Zhou Xiaosi
School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu 210023, People's Republic of China.
J Phys Chem Lett. 2022 Jun 30;13(25):5726-5733. doi: 10.1021/acs.jpclett.2c01299. Epub 2022 Jun 17.
As a typical layered transition metal chalcogenide, VS is considered as a promising cathode material for advanced magnesium-ion batteries. However, the poor electronic conductivity and severe polarization effect restrict its practical applications. Herein, we report a betaine-assisted solvothermal strategy to coat VS nanoblocks on the surface of carbon nanotubes (CNTs), obtaining unique core-shell-structured CNT@VS nanonecklaces. As a result of the morphology-controlling effect of betaine, VS exhibits an unusual nanoblock morphology, which renders abundant active sites and promotes the contact between the electrode and electrolyte. CNTs serve as a highly conductive skeleton, combining with the VS nanoblocks and ensuring their uniform distribution. As a benefit from the synergistic effect of abundant active sites and electron-conductive highways, the as-synthesized CNT@VS nanonecklaces manifest remarkable performance for magnesium storage, including a large reversible capacity of 170 mAh g at 0.1 A g, outstanding cycle stability (76.3 mAh g after 800 cycles at 0.5 A g), and superior rate performance (77.2 mAh g at 2 A g).
作为一种典型的层状过渡金属硫族化合物，VS被认为是一种用于先进镁离子电池的有前景的正极材料。然而，其较差的电子导电性和严重的极化效应限制了它的实际应用。在此，我们报道了一种甜菜碱辅助的溶剂热策略，用于在碳纳米管（CNT）表面包覆VS纳米块，从而获得独特的核壳结构CNT@VS纳米项链。由于甜菜碱的形貌控制作用，VS呈现出不寻常的纳米块形貌，这提供了丰富的活性位点并促进了电极与电解质之间的接触。碳纳米管作为高导电骨架，与VS纳米块结合并确保它们均匀分布。得益于丰富的活性位点和电子传导通道的协同效应，所合成的CNT@VS纳米项链在镁存储方面表现出卓越性能，包括在0.1 A g下具有170 mAh g的大可逆容量、出色的循环稳定性（在0.5 A g下800次循环后为76.3 mAh g）以及优异的倍率性能（在2 A g下为77.2 mAh g）。
