Revealing active sites storage mechanism of organic CO/CN compounds for ultralong-life aqueous zinc-ion batteries

Organic zinc-ion batteries (ZIBs) have been widely studied presently for high capacity, long lifespan, and sustainability of organic CO/CN materials, yet active sites storage mechanism is still unknown. Herein, a CO/CN material of HATTAQ (Hexaazatriphenylene-trianthraquinone) has been designed. Through in-situ experiments and theoretical calculations, the optimal structure of HATTAQ-1Zn-10H is acquired by analyzing 10 more possible discharging products. Besides, there systemically illustrates detailed active sites during formation of HATTAQ-1Zn-10H. One inner CN and one outer CO bind with Zn²⁺ then H⁺ insertion. Initially, H⁺ insert in one CN and one CO in para-position followed by reaction of H⁺ with 4 internal CN and 4 external CO. As expected, HATTAQ ZIBs show long cycle life of 12,000 cycles with 91 % capacity retention. Impressively, flexible HATTAQ ZIBs with a stable capacity are firstly used in wearable sensors. Prospectively, this work would provide ideas into active sites storage mechanism of organic ZIBs.