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

Abstract

For 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−.

Ce ions and polyaniline co-intercalation into MOF-derived porous V2O5 nanosheets with a synergistic energy storage mechanism for high-capacity and super-stable aqueous zinc-ion batteries

“…3h. 24,27,43–48 It is worth mentioning that the CPVO cathode can provide an energy density of 204 W h kg −1 even at a high power density of 8598 W kg −1 , significantly better than that of many reported state-of-the-art cathode materials (Table S2, for detailed comparison†).…”

2D Layered MnO2 with an Ultralarge Interlayer Spacing for Aqueous Zinc Ion Batteries

“…To overcome these problems, researchers have proposed various strategies, including nanostructure design, , composites with conductive polymers, preintercalation, − and defect engineering, to improve the electrochemical performance of δ-MnO 2 cathodes. In particular, the preintercalation strategy has proven to be a fundamental and highly effective approach for enhancing the capacity, cycle stability, and rate capability of a δ-MnO 2 cathode. , Preintercalated ions or molecules play a crucial role in increasing the interlayer spacing, facilitating ion transfer, and serving as “structural pillars” to prevent structural collapse. − Meanwhile, preintercalation can efficiently fine-tune the electronic structure of the host materials, leading to significant acceleration of electron-transfer processes. − Various ions and molecules have been previously investigated, including alkali ions, ,− NH 4 + , tetramethylammonium, Cu 2+ , Zn 2+ , Ba 2+ , La 3+ , Sn 4+ , Mo 4+ , and polyaniline . Chao et al incorporated Ba 2+ ions as interlayer pillars into δ-MnO 2 , which expanded the interlayer spacing from 0.63 to 0.70 nm, hence improving the Zn 2+ intercalation kinetics and enhancing the structural stability of δ-MnO 2 .…”

“…The interlayer spacing of layered cathodes usually shortens during the discharge process due to the strong electrostatic attraction between Zn 2+ and the host layers . An expanded interlayer spacing with reduced electrostatic repulsion not only will favor the ionic diffusion kinetics but also can diminish the volumetric variation of the cathode during ion insertion/extraction . Therefore, rational design of the interlayer spacing to realize highly stable and fast ion storage is of great importance for the development of δ-MnO 2 cathode material for AZIBs.…”

The importance of electrolyte environment during in situ self-transformation for synthesizing V2O5·nH2O

“…3a 1 and b 1 ). 7,21,22 The TEM images of VOH-1 reveal 0.34 nm lattice fringes, corresponding to the (5 0 0) plane (Fig. S5, ESI†).…”

“…3a 2 and b 2 ). 2,20,21 The peak at 304 cm −1 corresponds to the bending vibration of VO. The peaks at 507 and 725 cm −1 correspond to the stretching vibrations of V 3 –O and V 2 –O.…”