Diboron-porphyrin monolayer: a cathode material for aluminum-ion batteries

To examine the suitability of diboron porphyrin (DP) for aluminum-ion batteries (AIBs), the adsorption of AlCl4 on DP monolayer is studied using the density functional theory (DFT) computations. The strength of AlCl4 adsorption on DP is found comparable to graphene and slightly more than graphdiyne. The thermal stability of AlCl4 molecules on DP sheets at temperatures as high as 500 K is verified by ab-initio molecular dynamics (AIMD) simulations. A theoretical capacity of 337 mAhg−1 is predicted for AIBs based on DP monolayer. The semiconducting properties of a DP single layer change to metallic after the adsorption of AlCl4. This indicates that AlCl4 adsorption enhances the electrical conductivity of DP which is necessary for electrode material in AIBs. The low diffusion barrier with low voltage confirms the fast charging and discharging processes in the DP-based AIBs. Our results prove that a monolayer of DP can be a proper cathode material in AIBs.