Analysis of AlN monolayer as a prospective cathode for aluminum-ion batteries

Developing cathode materials with high specific capability and excellent electrochemical performance is crucial for the advancement of aluminum-ion batteries, which leverage the high theoretical energy density of aluminum metal anodes. In this paper, we investigated the interaction ofAlCl4cluster and Al atom with AlN (-100) and (001) monolayer using density functional theory to assess the applicability of AlN as cathode material for aluminum-ion batteries. The results show that the AlN (001) monolayer is the most effective for adsorbing and accommodatingAlCl4clusters. Moreover, the AlN (001) monolayer maintains metallic behavior at different concentrations of theAlCl4cluster, laying the foundation for its battery application. The theoretical storage capacity of theAlCl4cluster is 105.93mAhg-1,which exceeds that of the Al/graphite battery. The formation energy ofAlCl4-intercalated AlN compounds is -2.74 eV, and the intercalant gallery height is moderate. Furthermore, the diffusion barrier of 0.19 eV forAlCl4cluster between the AlN (001) monolayer provides high rate capability. The results indicate that AlN monolayer may be a potential cathode material for aluminum-ion batteries.