High Performance and Flexible Aqueous Zinc Batteries Using N-Containing Organic Cathodes

Aqueous zinc batteries are considered as one of the most promising energy storage systems for large-scale energy storage and wearable electronics, owing to their low cost and intrinsic safety. However, cathode materials that can reversibly host Zn²⁺ are still less. Here, we demonstrate that two N-containing organic compounds, hexamethoxy hexaazatrinaphthylene (HMHATN) and hexaazatrinaphthylene (HATN), used as cathodes can exhibit excellent reversible Zn²⁺ storage capability with fast kinetics and the high capacity of 542 and 963 mA h g^-1, respectively. The Zn//HMHATN and Zn//HATN full batteries display the high energy density of 160 and 221.6 W h kg^-1, respectively, and long-term cycling stability. Further, we investigate the mechanism of Zn²⁺ storage in the cathodes. More importantly, the flexible aqueous Zn//HMHATN and Zn//HATN batteries fabricated also have high capacity, long-term cycling life and impressive energy density, displaying its application prospect in wearable electronics. Our work opens a new system for finding organic cathode materials used in aqueous zinc batteries.