Textured Na₂V₆O₁₆·3H₂O Cathode Tuned via Crystal Engineering Endows Aqueous Zn-Ion Batteries with High Rate Capability and Adequate Lifespan

Abstract

Aqueous zinc-ion batteries (ZIBs) play a vital role in large-scale energy storage for smart grids due to their environmental friendliness, safety, and low cost. Unfortunately, the application of ZIBs has been challenged by the relatively low capacity of cathode materials, especially at higher rates, which originates from the sluggish diffusion of Zn ions. Herein, a crystal engineering strategy is explored for using bernesite, Na 2 V 6 O 16 •3H 2 O (NVO), for regulating the diffusion-preferable texture, which was beneficial for fostering Zn ions' diffusion and thus guaranteeing a uniform concentration inside the cathode. An enlarged capacity at a higher rate was obtained, delivering a capacity of 156.9 mAh g −1 at the ultra-high current density of 20 A g −1 , of which 140.6 mAh g −1 remained after 5000 cycles. The use of crystal engineering to regulate the texture of cathode materials paves the way to boost the application of NVO in aqueous ZIBs, which could be translated to design state-of-the-art cathodes for other battery systems.

Designing strategies of advanced electrode materials for high-rate rechargeable batteries

“…Xiong et al tuned the textured Na 2 V 6 O 16 $3H 2 O via a crystal engineering to avoid undesirable phase transition and regulate the effective Zn 2+ transfer pathway. 231 From the multiphysics simulation in Fig. 7g, with the increasing depth of discharge, the textured NVO guaranteed the uniform concentration eld of Zn ions and electric eld inside the electrode.…”

“…However, the hollow structure sacrices the volumetric energy density of the electrode to a certain extent. 231 Copyright 2022, American Chemical Society. (h) Computational study of K-ion diffusion pathways and the schematics of low energy barrier.…”

“…230 Copyright 2022, Elsevier. (g) Multiphysical simulation of the textured NVO cathode 231. Copyright 2022, American Chemical Society.…”

Spatiotemporal Resolution of Phase Formation in Thick Porous Sodium Vanadium Oxide (NaV3O8) Electrodes via Operando Energy Dispersive X-ray Diffraction

“…At 50, 100, 200, 500, and 1000 mA/g, NVO(300) delivers capacities of 2.35 (389), 1.88 (312), 1.70 (286), 1.57 (260), and 1.40 (231) mAh/cm 2 (mAh/g), which are 19, 19, 27.5, 44.4, and 69.9% higher than NVO(500). The higher rate capability and capacity for the NVO(300) material has previously been attributed to a higher effective diffusion coefficient compared to NVO(500), 18,30 while the increased capacity retention of NVO(500) is attributed to greater stability of the overall structure due to a surface limited Zn insertion resulting from the larger crystallite size and less hydrated interlayer. 19 Further analysis of the voltage profiles was conducted.…”

Chrysanthemum-like Polyaniline-Anchored PANI0.22·V2O5·0.88H2O-Hybridized Cathode for High-Stable Aqueous Zinc-Ion Batteries

“…To tackle these problems, a series of guest ions/molecules preintercalated in V-based oxide materials are proposed to stabilize their crystal frameworks and enlarge the interlayer spacing for facile Zn 2+ diffusion. However, most hetero ions are redox inactive and are liable to be extracted irreversibly during the repeat discharge processes, which will be at the expense of the overall reversible capacity of the materials. − Recent investigations demonstrate that introducing conductive organic small molecules [poly­(3,4-ethylene dioxythiophene), polyaniline, etc. ] to the interlayer of layered oxides allows for interlayer regulation and stabilizing structures via forming hydrogen bonds between the −NH 2 group and the V–O layer. − However, most of the so-called preinserted hydrated V 2 O 5 materials exhibit 2D belt-like or sheet-like architectures with relatively low specific surface areas.…”