Dual Effects of Metal and Organic Ions Co‐Intercalation Boosting the Kinetics and Stability of Hydrated Vanadate Cathodes for Aqueous Zinc‐Ion Batteries

Abstract

AbstractFor the development of aqueous zinc‐ion batteries, exploiting vanadium‐based cathode materials with quick kinetics and acceptable cycling stability is crucial. Herein, to achieve these goals, transition metal ions (Zn2+) and organic ions (C5H14ON+ and Ch+) are introduced into layered hydrated V2O5. The intrinsic high conductivity of Ch+ and the oxygen vacancies generated through ion pre‐intercalation accelerate the electrical mobility by optimizing the electronic structure. The Zn2+ stabilizes the layered structure and the expanded interlayer spacing improves the ionic diffusivity. The synergistic effect of pre‐intercalated Zn2+ and Ch+ results in the (Zn0.1, Ch0.1)V2O4.92·0.56H2O cathode exhibiting a discharge capacity of 473 mAh g−1 at 0.1 A g−1 with a high energy efficiency of 88% and excellent cycling stability with 91% retention after 2000 cycles at 4 A g−1. Ex situ characterizations and density functional theory calculations reveal a reversible intercalation mechanism of Zn2+, and the improved electrochemical kinetics are attributed to the altered electronic conductivity and the reduced binding energy between Zn2+ and host O2−.