Novel Organic Cathode\nwith Conjugated N‑Heteroaromatic\nStructures for High-Performance Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) are being considered\nnew choices\nof batteries not only because of their inherent safety but also because\nof their low price advantage. Nevertheless, it is still an important\ntask to develop organic cathode materials with green sustainability\nand high performance. Hexaazatriphenylene (HAT)-based organic materials\nhave shown great potential for use in AZIBs. Herein, 5,6,11,12,17,18-hexaazatrinaphthylene-2,8,14-tricarboxylic\nacid (HATTA) is designed and prepared as the AZIB cathode. Benefiting\nfrom the conjugative effect of −COOH, extended π-conjugated\nstructure, and abundant active sites, the HATTA electrode exhibits\na high capacity (225.8 mA h g^–1 at 0.05 A g^–1), an outstanding rate performance (136.1 mA h g^–1 at 25 A g^–1), and a long-term cycling\nlifespan (84.07% of the initial capacity after 10,000 cycles at 25\nA g^–1). Meanwhile, the characterization results\nof ex situ spectroscopic tests prove that the unsaturated bond (CN)\nis the redox-active moiety of HATTA. In addition, the flexible Zn//HATTA\nbattery also exhibits impressive long-term cycling stability and good\nflexibility, showing its promising application in wearable electronics.\nThis work provides a strategy with rational designing for constructing\nhigh-performance AZIBs with organics.