A High‐Voltage Organic Cathode Enabled by a Continuous Electronegativity Zone in Aqueous Zinc‐Organic Batteries
Runmo Wang, Yu Zhang, Chengbin Ma, Xiangbo Wang, Mian Cai, Huiping Du, Ze Yang, Dongliang Chao, Yaqun Wang
Abstract
Abstract N‐type organics serve as cathode materials for aqueous zinc‐ion batteries, exhibiting high theoretical capacity. However, their operating voltage is typically lower than 1 V (vs Zn 2+ /Zn), which significantly restricts the enhancement of the energy density and the practical application of these batteries. To address this issue, an imine compound 3‐5,6,11,12‐tetraazanaphthacene (3TANC) is designed, characterized by a continuous negative electrostatic potential region. This feature results in lower lowest unoccupied molecular orbital (LUMO) energy levels and enables a high average discharge voltage of 1.05 V (vs Zn 2+ /Zn). The elevated operating voltage allows 3TANC to achieve an energy density of 215 Wh kg −1 at 0.1 A g −1 . Furthermore, the capacity is maintained at 94.38% after 1000 cycles at 2 A g −1 . Additionally, 3TANC demonstrates the ability for NH 4 + storage, exhibiting a high average discharge voltage of −0.1 V (vs SCE) and offers a specific discharge capacity of 267.84 mAh g −1 at 0.1 A g −1 . Moreover, 3TANC's ammonium‐ion half‐cells maintain 100% capacity after 2100 cycles at 5 A g −1 . The Zn||3TANC hybrid ion cell exhibits exceptional cycling stability in 2 m (NH 4 ) 2 SO 4 electrolyte, achieving 90.23% capacity retention over 13800 cycles at 2 A g −1 . This work presents a novel approach for designing high‐voltage organic cathodes.