<i>n</i> ‐type Organic Cathodes Containing Multiple Imine Groups for Aqueous Aluminum Batteries

Organic cathodes have gained increasing attention in the field of aqueous batteries due to their molecular design flexibility and environmental friendliness. Among them, n-type organic compounds are favored for their unique ionic coordination mechanism and high capacity due to multiple active centers. Herein, an organic material, Diphenazino[2,3-b](5,6,12,13-tetrahydropyrazino[2',3':9,10]phenanthro[4,5-fgh]quinoxaline) (DTPQ) enriched with multiple C═N groups is designed by hot solvent condensation as rechargeable aqueous aluminum batteries (AABs) cathodes. The enriched imine group as active centers provides good specific capacity and capacity retention and exhibits excellent reaction kinetics. The extension of the π-conjugated structure also enables DTPQ to exhibit excellent rate capability while ensuring structural stability. In addition, theoretical calculations confirm the improvement of ion storage redox kinetics by the π-conjugate extension brought about by the rich electronic states and high aromatic backbone. Meanwhile, the storage mechanism of the imine group for Al-containing cations is explained by a series of ex situ characterizations. New ideas are provided for the design and application of n-type organic cathodes in AABs.