Engineering kinetics-favorable 2D graphene@CuS with long-term cycling stability for rechargeable magnesium batteries

Rechargeable magnesium batteries (rMBs) are regarded as one of the most promising next-generation energy storage devices due to their safe, cost-effective, and dendrite-free Mg deposition advantages. However, a great challenge still continues for the development of rMBs due to lacking capable cathodes with favorable electrochemical reaction kinetics and excellent structural stability. To achieve high electrochemical performances in rMBs, electrochemical reaction kinetics and structural stability of cathode materials should be enhanced by material design and optimization. Herein, the graphene-supported CuS nanosheets (CuS@rGO) with surface-to-surface two-dimensional architecture are fabricated by a facile microwave inorganic chemical synthesis method. By stacking CuS nanosheets on reduced graphene oxide, it is found that the Mg²⁺ cations storage performances can be significantly improved. The CuS@rGO positive-electrode can deliver a high discharge capacity of 421 mAh g⁻¹ at 50 mA g⁻¹ current density. A specific capacity of 51 mAh g⁻¹ is maintained after 500 cycles at 1000 mA g⁻¹ current density. Such excellent electrochemical performances could be ascribed to the conductive network construction of the two-dimensional CuS@rGO. The CuS@rGO can serve as a promising cathode material for rechargeable magnesium batteries.