First-Principles Study of 3-MoS for High-Capacity and Stable Aluminum Ion Batteries Cathode Material.

Currently, exploring high-capacity, stable cathode materials remains a major challenge for rechargeable Aluminum-ion batteries (AIBs). As an intercalator for rechargeable AIBs, Al produces three times the capacity of AlCl when the same number of anions is inserted. However, the cathode material capable of producing Al intercalation is not a graphite material with AlCl intercalation but a transition metal sulfide material with polar bonding. In this paper, the insertion mechanism of Al in 3-MoS is investigated using first-principles calculations. It is found that Al tends to insert into different interlayer positions at the same time rather than occupying one layer before inserting into another, which is different from the insertion mechanism of AlCl in graphite. Ab initio, molecular dynamics calculations revealed that Al was able to stabilize the insertion of 3-MoS. Diffusion barriers indicate that Al preferentially migrates to nearby stabilization sites in diffusion pathway studies. According to the calculation, the theoretical maximum specific capacity of Al intercalated 3-MoS reached 502.30 mAg h, and the average voltage of the intercalation was in the range of 0.75-0.96 V. Therefore, 3-MoS is a very promising cathode material for AIBs.