Rechargeable magnesium batteries (RMBs) have been considered as promising candidates for large-scale energy storage devices due to their high safety and high energy density. However, searching for cathode materials with excellent cycling stability remains a major challenge hindering their development. In this work, we investigated, for the first time, the effects of different solvent systems on the composition and electrochemical performance of a material. The results showed that the final product is a CuCo₂S₄/CuS composite when deionized water is used as the solvent, in which CuCo₂S₄ appears as sheets and CuS has a bulk morphology. CuCo₂S₄/CuS had the highest first discharge specific capacity, while its cycling performance was poor. Therefore, we successfully synthesized a CuCo₂S₄/CuS@MWCNTs composite as a cathode material for RMBs with the addition of an appropriate amount of MWCNTs to enhance the cycling stability. The electrochemical results showed that CuCo₂S₄/CuS@MWCNTs (15 wt %) exhibits a high initial discharge specific capacity of 214.79 mAh g^–1 at 10 mA g^–1 and 118.29 mAh g^–1 at 300 mA g^–1, excellent rate performance, and long cycle stability over 1000 cycles at 300 mA g^–1. These results demonstrated that the CuCo₂S₄/CuS@MWCNTs composite is a promising cathode for RMBs with long cycle life.

中文翻译：

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CuCo2S4/CuS@MWCNTs复合材料作为可充电镁离子电池的阴极，具有长循环寿命

可充电镁电池（RMBs）由于其高安全性和高能量密度而被认为是大规模储能设备的有希望的候选者。然而，寻找具有优异循环稳定性的正极材料仍然是阻碍其发展的主要挑战。在这项工作中，我们首次研究了不同溶剂体系对材料组成和电化学性能的影响。结果表明，以去离子水为溶剂，最终产物为CuCo ₂ S ₄ /CuS复合物，其中CuCo ₂ S ₄呈片状，CuS呈块状。铜钴₂ S ₄/CuS的首次放电比容量最高，但循环性能较差。因此，我们成功地合成了CuCo ₂ S ₄ /CuS@MWCNTs 复合材料作为RMBs的正极材料，并添加了适量的MWCNTs 以提高循环稳定性。显示的电化学结果CUCO ₂小号₄ / @硫化铜多壁碳纳米管（15重量％）显示出214.79毫安g的高的初始放电比容量^-1在10mA克^-1和118.29毫安克^-1在300mA克^-1，优异的倍率性能，以及在 300 mA g ^{–1 下}超过 1000 次循环的长循环稳定性。这些结果表明，CuCo ₂S ₄ /CuS@MWCNTs 复合材料是一种具有长循环寿命的有前途的人民币正极。