A High‐Potential Bipolar Phenothiazine Derivative Cathode for Aqueous Zinc Batteries

Abstract Aqueous zinc ion batteries (AZIBs) are gaining popularity as advanced energy storage devices that are economical, safe, and use resource‐abundant storage options. In this study, we have synthesized a bipolar phenothiazine organic scaffold known as 3,7‐bis(melaminyl)phenothiazin‐5‐ium iodide (PTDM), which is obtained by undergoing nucleophilic substitution through phenothiazinium tetraiodide hydrate (PTD) and melamine. Electrochemical results indicate that PTDM can act as a high‐potential cathode material for rechargeable AZIBs. In detail, the aqueous PTDM//Zn full cell exhibits a high average voltage of approximate 1.13 V, along with a specific capacity of 118.3 mAh g−1 at 0.1 A g−1. Furthermore, this demonstrated cell displays moderate long‐term cycling stability over 6400 cycles, which is encouraging and suggests potential for developing advanced organic electrode materials for rechargeable AZIBs.