H2O Activity Adjustment by Hydrogen Bonding Enables High‐Performance Zn‐Organic Battery

Abstract The advantages of low cost and high safety of zinc (Zn) metal have attracted much attention on its application in batteries, but H 2 O‐induced issues of hydrogen evolution reaction (HER), Zn corrosion, and Zn dendrites formation limit the application. Here, a strategy of adjusting H 2 O activity was provided by adding glycerol (GL) and acetonitrile (AN) into aqueous electrolyte to form hydrogen bonds between organic solvents and H 2 O, which alleviated the Zn corrosion. Furthermore, molecular dynamics (MD) simulation indicated that GL could exclude H 2 O from the Zn 2+ solvation shell, thus preventing undesired HER and Zn dendrites formation. Therefore, the corresponding Zn//Zn symmetrical cell showed a ultralong lifespan (1300 h). Then, a Zn‐organic battery with 3,7‐dimorpholino‐phenothiazin‐5‐ium iodide (FD28) cathode was fabricated by using such electrolyte. Interestingly, the reduced H 2 O activity also ensured the stable operation of organic cathode, and thus the full cell showed superior cycle stability for over 9000 cycles (≈1100 h), which is superior to previous reports. Moreover, such electrolyte owns novel properties of nonflammability, great weatherability, and low freezing point, thus boosting the practicality of the battery.