Long-Term Cycling Stability of Cobalt sulfide Nanosheets for High-Performance Magnesium-Ion Batteries

Rechargeable Magnesium ion batteries (RMIBs) are considered one of the most promising energy storage devices due to their low cost, dendrite-free nature, and ecofriendliness. However, sluggish kinetics, irreversible structural changes, short cycle life, and low capacity of cathodes hinder their practical applications. Herein, Cobalt sulfide (CoS₂) nanosheets are synthesized using microwave method followed by chemical vapor deposition to serve as cathode material for RMIBs. CoS₂ nanosheets exhibit excellent electrochemical performance, providing a high specific capacity of 432 mAh g⁻¹ at 100 mA g⁻¹ current density. Moreover, CoS₂ also demonstrates a long-term operating stability over 2000 cycles giving 284 mAh g⁻¹ capacity at a current density of 500 mA g⁻¹ with approximately 96% capacity retention. Sustainable cathodic performance is the most desirous feature for commercialization. The density functional theory and experimental results reveal that the robust electrochemical performance of CoS₂ as a cathode is attributed to the high surface area of its sheet-like morphology. This work provides meaningful insights regarding morphological limitations and opportunities of CoS₂ cathode for applications in high-performance RMIBs.