ScS2 Monolayer as a Potential Cathode Material for Alkali-ion Batteries and Beyond
Abstract
Sc is the lightest transition metal that could help to achieve the goal of high theoretical capacity. Hence, we here explored the performance of ScS2 monolayer as a cathode material for alkali-ion batteries (Li, Na, K) and other multi-valent metal-ion batteries (Mg, Al). Previous studies on ScS2 have focused only on the fundamental electronic and magnetic properties of the ScS2 monolayer, but not on its possible applications. Our first-principles calculations show that 2D ScS2 is able to deliver a large theoretical capacity of 491.36 mAh g-1 for alkali-ions and 324.29 mAh g-1 for Mg and Al-ions while maintaining good average open-circuit voltages. We also studied the diffusivity of these metal ions on the ScS2 surface which is related to the charge/discharge rate capability of batteries. Our results suggest low diffusion barriers for all metal ions except Al. Owing to these results, we, therefore, believe that the ScS2 monolayer can be an interesting candidate for cathode material to be used in alkali-ion batteries and beyond.