Microwave-anion-exchange route to spinel CuCo₂S₄ nanosheets as cathode materials for magnesium storage

Exploring high-performance cathode materials is of great significance for development of rechargeable magnesium batteries. Herein, two-dimensional ultrathin spinel CuCo₂S₄ nanosheets synthesized via microwave-assisted liquid-phase growth and anion-exchange post-sulfuration method. As a magnesium storage material, the electrochemical behavior of the CuCo₂S₄ nanosheets is investigated in different voltage ranges. After activated for several cycles in 0.1–2.1 V, the CuCo₂S₄ nanosheet material can show good electrochemical reversibility between 0.1 and 2.0 V with capacity of 191.4 mAh g⁻¹ (50 mA g⁻¹) and 114.5 mAh g⁻¹ (500 mA g⁻¹). The excellent Mg-storage properties are attributed to the fast kinetics of Mg²⁺ by the 2D morphology and ternary structure. A conversion reaction of the magnesium ion storage mechanism is confirmed by ex situ X-ray diffraction characterization. The excellent performance of spinel CuCo₂S₄ nanosheets validates the viability of the multinary strategy and sheds light on the application of 2D material design for cathode research.