Enhanced π-conjugation and multi-electron transfer organic cathodes enabled high-performance zinc-ion storage

Small-molecule imine compounds have attracted increasing attention as cathode materials for aqueous zinc-ion batteries (AZIBs) due to the high redox activity of the CN functional group. However, the inherently low electronic conductivity of organic small molecules, combined with their high solubility and the formation of unfavorable discharge products in aqueous electrolytes, significantly hampers their electrochemical performance. Herein, we report the synthesis of an imine-based compound, dipyrido[3,2-a:2',3'-c]quinoxalino[2,3-i]phenazine (DPQPZ), featuring six redox-active sites, intermolecular π-π stacking interactions, and a fully conjugated two-dimensional planar structure with delocalized electron distribution. These structural features synergistically enhance both the reversible capacity and cycling stability, positioning DPQPZ as a promising organic cathode material for high-performance zinc-ion storage. Notably, the DPQPZ electrode delivers a high specific capacity of 398.5 mAh g^-1 at 0.1 A g^-1, approaching its theoretical capacity of 418 mAh g^-1. Furthermore, the extended π-conjugated framework reinforces intermolecular interactions, effectively suppressing material dissolution in aqueous electrolytes. As a result, the electrode exhibits remarkable cycling stability, with 88.7 % capacity retention after 8000 cycles at a high current density of 10 A g^-1.