Construction of VS2/VOx Heterostructure via Hydrolysis-Oxidation Coupling Reaction with Superior Sodium Storage Properties |
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Authors: | Yuxiang Zhang Yangziyu Chen Yan Jiang Jing Wang Xiangyi Zheng Bo Han Kaisheng Xia Qiang Gao Zhao Cai Chenggang Zhou Ruimin Sun |
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Affiliation: | Faculty of Materials Science and Chemistry, China University of Geosciences (Wuhan), Wuhan, 430074 China |
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Abstract: | Heterostructure engineering is one of the most promising modification strategies for reinforcing Na+ storage of transition metal sulfides. Herein, based on the spontaneous hydrolysis-oxidation coupling reaction of transition metal sulfides in aqueous media, a VOx layer is induced and formed on the surface of VS2, realizing tight combination of VS2 and VOx at the nanoscale and constructing homologous VS2/VOx heterostructure. Benefiting from the built-in electric field at the heterointerfaces, high chemical stability of VOx, and high electrical conductivity of VS2, the obtained VS2/VOx electrode exhibits superior cycling stability and rate properties. In particular, the VS2/VOx anode shows a high capacity of 878.2 mAh g?1 after 200 cycles at 0.2 A g?1. It also exhibits long cycling life (721.6 mAh g?1 capacity retained after 1000 cycles at 2 A g?1) and ultrahigh rate property (up to 654.8 mAh g?1 at 10 A g?1). Density functional theory calculations show that the formation of heterostructures reduces the activation energy for Na+ migration and increases the electrical conductivity of the material, which accelerates the ion/electron transfer and improves the reaction kinetics of the VS2/VOx electrode. |
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Keywords: | anode materials heterostructures hydrolysis-oxidation coupling reactions sodium-ion batteries VS
2/VO
x |
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