Cationic Co-doping in copper sulfide nanosheet cathodes for efficient magnesium storage

Sluggish kinetics and inferior redox reversibility have limited the further development of the CuS cathode material in advanced rechargeable magnesium batteries. Herein, a cation-doping strategy is reported to regulate the electrochemical Mg²⁺ storage behaviors of Co-doped CuS nanosheet cathodes via an effective microwave assisted synthesis technique. With cationic Co-doping, the fast electrochemical diffusion kinetics and optimized reversible redox reaction could be achieved over Co-doped CuS nanosheet cathodes. Specifically, the optimized Co-doped CuS nanosheet cathodes deliver excellent reversible capacity of 297 mAh g⁻¹ under 200 mA g⁻¹, outstanding rate capabilities of 143.4 mAh g⁻¹ at 1.0 A g⁻¹, and enhanced long-term cyclic life with 0.0722 % capacity decay of per cycle at 1.0 A g⁻¹. The enriched electrochemical performance of Co-doped CuS nanosheet cathodes can be attributed to the cation-doping effect that could efficiently shield the strong Coulombic effect among magnesium ions and host anions to accelerate Mg²⁺ diffusion kinetics. Therefore, the cationic Co-doping strategy provides a novel avenue to regulate the favorable cathode reaction for rapid magnesium storage.