Constructing sheet-assembled hollow CuSe nanocubes to boost the rate capability of rechargeable magnesium batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 9; no. 6; pp. 3648 - 3656
• Main Authors: Du, Changliang, Younas, Waqar, Wang, Zhitao, Yang, Xinyu, Meng, Erchao, Wang, Liqin, Huang, Jiaqin, Ma, Xilan, Zhu, Youqi, Cao, Chuanbao
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 16.02.2021
• Subjects: ambient temperature; Cathodes; Charge density; Conversion; Copper; Copper converters; Copper selenides; Copper sulfides; Discharge; Electrochemistry; Electrode materials; Electrode polarization; electrolytes; Ion diffusion; Magnesium; Morphology; Rechargeable batteries; Room temperature; Selenide; selenides; Specific capacity; Structural hierarchy; Sulfides; Ultrahigh temperature
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/d0ta10708e

Copper selenide has been considered as a much more promising conversion-type cathode material for rechargeable magnesium batteries than copper sulfide because of its better conductivity. However, the magnesium ion diffusion in the lattice of the CuSe host is subject to a great coulombic resistance due to the relatively high charge density and ion polarization of the divalent Mg 2+ , leading to undesired rate capability and low reversible capacity. Herein, a morphology engineering strategy is presented to construct sheet-assembled hollow CuSe nanocubes by a simple template-directed selenation reaction at room temperature. Electrochemical measurements suggest that the CuSe nanocubes could exhibit an ultra-high initial discharge capacity of 596 mA h g −1 and maximum specific capacity of 252 mA h g −1 and maintain a relatively high reversible capacity of 170 mA h g −1 after 100 cycles at 200 mA g −1 . Furthermore, a remarkable rate capability could be obtained with 77.6 mA h g −1 discharge capacity at 5 A g −1 . Additionally, the CuSe nanocubes exhibit excellent compatibility with Mg(BH 4 ) 2 /(CF 3 ) 2 CHOH/DME electrolyte and follow a two-step conversion mechanism. Such superior magnesium storage properties demonstrate that constructing a hierarchical hollow structure could be one of the effective methods to promote the magnesium storage kinetics of CuSe cathode materials. Sheet-assembled hollow CuSe nanocubes are fabricated by a facile template-directed selenation method and exhibit record rate capability among the chalcogenide compounds reported so far.