Hierarchical nanosheet-assembled copper sulfide microspheres as the cathode materials for rechargeable magnesium batteries

Rechargeable magnesium battery is an inexpensive, high-safety energy storage technology suitable for large-scale applications. However, its development is still hindered by lacking high-performance cathode materials. Herein, we present a simple one-step template-free hydrothermal method to synthesize hierarchical CuS microspheres self-assembled from nanosheets as the cathode materials for rechargeable magnesium battery. Owing to the special structure configuration, the as-synthesized CuS microspheres can exhibit a high specific capacity of 252 mAh g^–1 at 100 mA g^–1, and a reversible specific capacity of 171.2 mAh g^–1 at 500 mA g^–1. Additionally, the CuS microspheres also show good rate capability with 91.7 mAh g^–1 specific capacity at high current density of 1000 mA g^–1 and a long-term cycling stability over 500 cycles. These electrochemical results indicate that the fabrication of the CuS microspheres with hierarchical structure can provide an efficient route to develop high-performance copper sulfide cathode materials for emerging rechargeable magnesium batteries.