Multisite AlCl₂⁺ Coordination in Flower-like Zn-PTC Superstructures for High-Energy and Long-Life Aluminum-Organic...

Aluminum-organic batteries (AOBs), utilizing [AlCl_x]^(3-x)+ (x = 0-2) species in ionic liquid electrolytes (ILEs), hold promise for low-cost, high-energy storage. However, their development is hampered by poor redox accessibility and sluggish Al-ion coordination in conventional organic cathodes. Herein, we report a three-dimensional Zn(II)-coordinated perylenetetracarboxylic acid superstructure (Zn-PTC) as a high-capacity AOB cathode. The Zn-PTC framework features extended π-conjugation and abundant C═O, C-O, and OH groups, enabling reversible coordination with up to four AlCl₂⁺ ions per unit. Ex situ FTIR, XPS, XRD, and SEM confirm enolate-type redox activity and dynamic structural evolution. Zn-PTC exhibits an outstanding capacity of 1580 mAh g^-1 at 0.1 A g^-1 and retains 128 mAh g^-1 over 850 cycles at 1 A g^-1 in AlCl₃/urea ILE, with high energy density (1633 Wh kg^-1) and Coulombic efficiency (∼99.8%). The superior performance over AlCl₃/[EMIm]Cl IL (646 mAh g^-1 @ 0.1 A g^-1 and 97 mAh g^-1 @ 1 A g^-1) is attributed to enhanced ionic mobility and interfacial kinetics. This study demonstrates a viable supramolecular strategy to overcome coordination and solubility limitations in AOBs, advancing the design of robust, high-performance organic cathode materials.