First-Principles Investigation of Graphenylene as a Long-Life Cathode Material in Aluminum Ion Batteries

Aluminum ion batteries are a promising alternative to lithium ion batteries. However, many previous cathode materials may have limitations such as poor longevity. Large AlCl4 ions intercalate in the cathode, causing deformation and, subsequently, degradation of most cathode materials. Using first-principles density functional theory calculations, we have investigated the interaction between graphenylene and AlCl4 ions to improve aluminum ion battery performance. We have calculated the binding energy for one and two AlCl4 ions absorbed on the same substrate, and the energies are −1.812 and −1.446 eV, separately, which indicates that an increasing number of ions causes a decreasing binding strength. We have also calculated the energy barrier for an AlCl4 ion to diffuse on the substrate, which is 0.594 eV. This small energy allows for high ion mobility and cathode longevity. Finally, we conclude that graphenylene is a suitable cathode material for aluminum ion batteries.