A hollow CuS nanocube cathode for rechargeable Mg batteries: effect of the structure on the performance

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (37), p.2141-2142
• Main Authors: Shen, Jingwei, Zhang, Yujie, Chen, Dong, Li, Xue, Chen, Zhongxue, Cao, Shun-an, Li, Ting, Xu, Fei
• Format: Article
• Language: English
• Subjects: Cathodes; Copper sulfides; Cycles; Dendritic structure; Diffusion; Diffusion rate; Energy storage; Ion diffusion; Magnesium; Rechargeable batteries; Solid state; Storage batteries; Storage capacity; Storage systems; Thin walls
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta07470h

Rechargeable Mg batteries are potential candidates for large-scale energy storage systems due to highly abundant and dendrite-free Mg anodes. However, their performance is hindered by the bivalent Mg 2+ cation. A hollow structure is advantageous for Mg-storage cathodes because cavities could provide extra electrochemically active sites and a large electrolyte-electrode interface for fast Mg 2+ ion diffusion. In this work, three hollow CuS nanocubes are prepared by a facile method and comparatively investigated as Mg battery cathodes to obtain a comprehensive structure-performance relationship. It is observed that a dilute solution would result in small hollow CuS nanocubes with a thin wall and large specific surface area, which are favorable for solid-state Mg 2+ ion diffusion, and thus result in a high reversible Mg-storage capacity. The hollow structure is also favorable for a good cycling stability. The hollow CuS nanocube cathode could deliver a high reversible capacity of 200 mA h g −1 at 100 mA g −1 , a remarkable rate capability of 50 mA h g −1 at 1000 mA g −1 , and an excellent long-term cycling stability. Mechanism investigation demonstrates a conversion reaction during charge/discharge cycling. This work provides a promising cathode design strategy for rechargeable Mg batteries to overcome the sluggish solid-state Mg 2+ diffusion. Hollow CuS nanocubes are used as rechargeable Mg battery cathodes with fast solid-state Mg 2+ ion diffusion kinetics.