CuCo2S4/CuS@MWCNTs Composite as a Cathode for Rechargeable Magnesium-Ion Batteries with Long Cycle Life

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@MVVCNTs 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/CuSp 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)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.

Automated summary

Rechargeable magnesium batteries (RMBs) are promising candidates for energy storage devices, but finding cathode materials with excellent cycling stability remains a challenge. In this study, a CuCo2S4/CuS@MWCNTs composite was successfully synthesized as a promising cathode material for RMBs.