Interaction Mechanism between Cyano-Organic Molecular Structures and Energy Storage of Aluminum Complex Ions in Aluminum Batteries.

Aluminum ion batteries (AIBs) are widely regarded as the most potential large-scale metal ion battery because of its high safety and environment-friendly characteristics. To solve the problem of weak electrical conductivity of organic materials, different structures of cyano organic molecules with electrophilic properties are selected as the cathode materials of aluminum batteries. Through experimental characterization and density functional theory theoretical calculation, Phthalonitrile is the best cathode material among the five organic molecules and proved that the C≡N group is the active site for insertion/extraction of AlCl ions. The first cycle-specific capacity of the assembled flexible package battery is as high as 191.92 mAh g , the discharge-specific capacity is 112.67 mAh g after 1000 cycles, and the coulombic efficiency is ≈97%. At the same time, the influences of different molecular structures and functional groups on the battery are also proved. These research results lay a foundation for selecting safe and stable organic aluminum batteries and provide a new reference for developing high-performance AIBs.