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 ma-terial 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.