image: Schematic representation of Zn2+ migration in vanadium oxide (VO) intercalated with three types of organic carboxylic acids: monocarboxylic acids, dicarboxylic acids, and polycarboxylic acids. Glycine (Gly), DL-Alanine (DL-Ala), Oxalic acid (OA), Malonic acid (MA), Glutaric acid (GA), 2,5-Thiophenedicarboxylic acid (OB), Iminodiacetic acid (IDA), 1,2,3-Propanetricarboxylic acid (TA), Citric acid (CA), Nitrilotriacetic acid (NTA), Ethylenediaminetetraacetic acid (EDTA).
Credit: ©Science China Press
Aqueous zinc-ion batteries (AZIBs) are considered one of the most promising sustainable energy storage devices and an alternative to lithium-ion batteries due to their high safety, low cost (~2700 USD per Ton), high theoretical specific capacity (820 mAh g-1), and low redox potential (-0.76 V vs SHE). However, the development of AZIBs has been hindered by challenges such as the structural collapse of cathode materials and slow kinetics during charge and discharge processes. As a result, extensive and in-depth research has been conducted on manganese oxides, vanadium oxides, and Prussian blue analogs, with the aim of creating advanced AZIBs.
Vanadium oxides (VO) have attracted significant attention from researchers due to their multivalent states and complex crystal structures. However, two-dimensional layered VO still faces challenges, such as small interlayer spacing, susceptibility to structural collapse, and low ionic conductivity. Additionally, during charge and discharge processes, strong electrostatic repulsion between Zn2+ ions and their high degree of hydration slow down the electrochemical kinetics. To address these issues, researchers have precisely modulated the interlayer spacing by intercalating metal ions and organic molecules, providing sufficient space for Zn2+ migration and storage, thereby enhancing the energy storage efficiency of AZIBs. However, organic molecule intercalation guests have primarily been neutral electron donors in previous reports, while research on vanadium oxides intercalated with charged organic ligands remains scarce.
To address this issue, the research team led by Professor Huan Pang from Yangzhou University, inspired by the synthesis of metal-organic frameworks (MOFs), successfully prepared VO nanomaterials intercalated with charged organic carboxylic acid ligand through a one-step hydrothermal method. In this approach, organic carboxylic acid ligands, functioning as structural scaffolds, were employed as intercalation guests within two-dimensional layered materials. The study revealed that the synthesized VO nanomaterials exhibit uniform morphology and particle size, large interlayer spacing, and stable ion channels, facilitating the migration and storage of zinc ions during charge and discharge processes. Furthermore, the negatively charged organic carboxylic acid ligand reduce electrostatic interactions between zinc ions, promoting rapid ion migration. This work establishes a new connection between metal-organic frameworks and two-dimensional layered materials, offering fresh insights for materials synthesis.
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See the article:
Charged organic ligands inserting/supporting the nanolayer spacing of vanadium oxides for high-stability/efficiency zinc ion batteries
https://doi.org/10.1093/nsr/nwae336
Journal
National Science Review