Highly Branched VS4 Nanodendrites with 1D Atomic‐Chain Structure as a Promising Cathode Material for Long‐Cycling Magnesium Batteries. Issue 32 (25th June 2018) - Wang, Yanrong
Abstract: Rechargeable magnesium batteries have attracted increasing attention due to the high theoretical volumetric capacities, dendrite formation‐free characteristic and low cost of Mg metal anodes. However, the development of magnesium batteries is seriously hindered by the lack of capable cathode materials with long cycling life and fast solid‐state diffusion kinetics for highly‐polarized divalent Mg 2+ ions. Herein, vanadium tetrasulfide (VS4 ) with special one‐dimensional atomic‐chain structure is reported to be able to serve as a favorable cathode material for high‐performance magnesium batteries. Through a surfactant‐assisted solution‐phase process, sea‐urchin‐like VS4 nanodendrites are controllably prepared. Benefiting from the chain‐like crystalline structure of VS4, the S2 2‐ dimers in the VS4 nanodendrites provide abundant sites for Mg 2+ insertion. Moreover, the VS4 atomic‐chains bonded by weak van der Waals forces are beneficial to the diffusion kinetics of Mg 2+ ions inside the open channels of VS4 . Through a series of systematic ex situ characterizations and density functional theory calculations, the magnesiation/demagnesiation mechanism of VS4 are elucidated. The VS4 nanodendrites present remarkable performance for Mg 2+ storage among existing cathode materials, exhibiting a remarkable initial discharge capacity of 251 mAh g ‐1 at 100 mA g ‐1 and an impressive long‐term cyclability at large current density of 500 mA g ‐1 (74 mAh g ‐1 after 800 cycles). Abstract : VS4 nanodendrites with 1D atomic‐chain structure can serve as a favorable cathode material for magnesium batteries. The S2 2− dimers in VS4 provide abundant void sites for Mg 2+ insertion. The VS4 atomic chains are bonded by weak van der Waals forces, which are in favor of diffusion of Mg 2+ inside the open channels of VS4 and present remarkable performance for Mg 2+ storage.