Preparation method and application of zinc / aluminum-rich layered bimetallic oxide doped iodine elementary substance electrode
By preparing ZnAl-LDH@I2 composite electrode materials, the layered structure and weak interactions of iodine were used to load elemental iodine, thus solving the iodine dissolution and shuttle phenomenon and improving the electrochemical performance of zinc-iodine batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-03-27
AI Technical Summary
In the existing technology, the iodine dissolution and shuttle phenomenon of iodine-based cathodes leads to low capacity and short cycle life of zinc-iodine batteries, and existing improvement methods have limited effect.
ZnAl-LDH nanosheets were prepared by hydrothermal synthesis and then combined with iodine to form ZnAl-LDH@I2 composite electrode material. The layered structure and weak interactions of iodine provide space for insertion and extraction, and also enhance conductivity.
The ZnAl-LDH nanosheets and iodine composite electrode material prepared by hydrothermal synthesis solved the problems of iodine dissolution and shuttle, and improved the electrochemical performance of zinc-iodine batteries.
Smart Images
Figure CN121748260A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of zinc-iodine battery technology, specifically relating to a method for preparing and applying a zinc / aluminum-rich layered bimetallic oxide-doped iodine elemental electrode. Background Technology
[0002] Aqueous zinc-iodine batteries are electrochemical energy storage devices that use metallic zinc as the negative electrode, iodine-based materials as the positive electrode, and an aqueous electrolyte. These batteries have attracted widespread attention due to their high safety, high energy density, low cost, and environmental friendliness. Their positive and negative electrode active materials are iodine and zinc, respectively. These materials are not only safe and environmentally friendly, but zinc and iodine are also abundant in the Earth's crust, making them easy to mine and extract. This makes large-scale application of aqueous zinc-iodine batteries possible in the energy storage field.
[0003] However, iodine-based cathodes suffer from iodine dissolution and shuttle phenomena. Specifically, polyiodide ions dissolve into the electrolyte and diffuse towards the negative electrode, ultimately leading to low battery capacity and short cycle life. Currently, there are two main approaches to address this issue: one is to load iodine into porous carbon materials (such as activated carbon and graphene) or covalent organic frameworks (COFs); the other is to modify the electrolyte by introducing polyiodide anchoring agents (such as quaternary ammonium salts and MXene). However, current strategies involve loading iodine into porous carbon (such as activated carbon and graphene) or COFs to neutralize electrolyte modification, i.e., introducing polyiodide anchoring agents (such as quaternary ammonium salts and MXene). However, the improvement is limited and still cannot meet the requirements for zinc-iodine batteries. Summary of the Invention
[0004] This invention first synthesizes ZnAl-LDH nanosheets via hydrothermal synthesis, and then combines them with elemental iodine to form a ZnAl-LDH@I2 composite electrode material.
[0005] The ZnAl-LDH@I2 composite electrode material obtained by this invention is prepared by a two-step method of hydrothermal synthesis and iodine elemental sublimation. The final material exhibits excellent electrochemical performance when applied to zinc-iodine batteries.
[0006] The technical solution adopted in this invention is:
[0007] A method for preparing a zinc / aluminum-rich layered bimetallic oxide-doped iodine electrode includes the following steps:
[0008] 1) Dissolve zinc nitrate hexahydrate and aluminum nitrate nonahydrate in 60 mL of deionized water, then add urea and stir until completely dissolved. Then, transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene and place it in an oven for hydrothermal reaction. After the reaction is complete, allow it to cool naturally, centrifuge to collect the white precipitate, wash it with deionized water and ethanol, and finally dry the precipitate to obtain ZnAl-LDH nanosheets.
[0009] 2) ZnAl-LDH nanosheets and iodine were mixed, ground evenly, and then sealed in a glass bottle and heated. Subsequently, the iodine-loaded ZnAl-LDH nanosheets were ultrasonically mixed with conductive carbon in ethanol. The mixture was centrifuged and washed to obtain a precipitate. Finally, the precipitate was dried to obtain the ZnAl-LDH@I2 composite electrode material.
[0010] Furthermore, in the above preparation method, in step 1), the molar ratio of zinc nitrate hexahydrate and aluminum nitrate nonahydrate is 3:1.
[0011] Furthermore, in the above preparation method, step 1), the hydrothermal reaction conditions are 130°C for 24 hours.
[0012] Furthermore, in the above preparation method, step 1), the drying conditions are drying at 60°C overnight.
[0013] Furthermore, in step 2) of the above preparation method, the ZnAl-LDH nanosheets and elemental iodine are mixed at a mass ratio of 1:2.
[0014] Furthermore, in the above preparation method, step 2), the heating condition is heating at 60°C for 6 hours.
[0015] Furthermore, in step 2) of the above preparation method, the mass ratio of the iodine-loaded ZnAl-LDH nanosheets to conductive carbon is 7:3.
[0016] Furthermore, in the above preparation method, step 2), the ultrasonic mixing time is 1 hour.
[0017] Furthermore, in the above preparation method, step 2), the drying conditions are drying at 60°C overnight.
[0018] The application of ZnAl-LDH@I2 composite electrode material prepared by any of the above preparation methods as a positive electrode in zinc-iodine batteries.
[0019] Furthermore, in the above application, the zinc-iodine battery assembly method is as follows: ZnAl-LDH@I2 composite electrode material as the positive electrode, separator, and zinc foil as the negative electrode are sequentially loaded into a 2032 button cell, and electrolyte is added to obtain the battery.
[0020] Furthermore, in the above application method, the concentration of zinc iodide in the electrolyte is 0.2-0.5 mol / L, the concentration of zinc sulfate is 2-2.2 mol / L, and the solvent is deionized water.
[0021] Furthermore, in the above application method, the diaphragm is made of glass fiber.
[0022] The beneficial effects of this invention are:
[0023] 1. The ZnAl-LDH@I2 composite electrode material provided by this invention, with the help of the two-dimensional layered structure of the layered metal oxide and its weak interlayer interactions (such as van der Waals forces), allows ions or molecules to be inserted / extracted between the layers. Iodine is loaded in its two-dimensional layered structure, which can both protect the iodine and provide a suitable site for the insertion and extraction of iodine, thus ensuring the high conductivity of the composite material.
[0024] 2. This invention prepares a zinc / aluminum-rich layered bimetallic oxide by hydrothermal synthesis, which not only provides space for the doping of iodine, but also unlocks the vertical transport channel of the hydroxide layer, thus achieving the goal of significantly improving the performance of zinc-iodine batteries. Attached Figure Description
[0025] Figure 1 These are scanning electron microscope images of the ZnAl-LDH@I2 composite electrode material prepared in Example 1 at different magnifications.
[0026] Figure 2 These are scanning electron microscope images of the ZnAl-LDH nanosheets prepared in Comparative Example 1 at different magnifications.
[0027] Figure 3 The images show the XRD patterns of the ZnAl-LDH@I2 composite electrode material prepared in Example 1 and the ZnAl-LDH nanosheets prepared in Comparative Example 1.
[0028] Figure 4 These are the infrared spectra of the ZnAl-LDH@I2 composite electrode material prepared in Example 1 and the ZnAl-LDH nanosheets prepared in Comparative Example 1.
[0029] Figure 5 These are the charge-discharge curves of the ZnAl-LDH@I2 composite electrode material.
[0030] Figure 6 This is a scaling factor diagram of the ZnAl-LDH@I2 composite electrode material. Detailed Implementation
[0031] Example 1
[0032] 1) Dissolve 9 mM zinc nitrate hexahydrate and 3 mM aluminum nitrate nonahydrate in 60 mL of deionized water. Stir until completely dissolved, then add 0.8 M urea and stir until completely dissolved. Transfer the mixture to a 100 mL stainless steel reactor lined with polytetrafluoroethylene and react at 130 °C for 24 h. After the reaction is complete, allow to cool naturally, centrifuge to collect the white precipitate, wash three times with deionized water and ethanol, and dry the precipitate overnight at 60 °C to obtain ZnAl-LDH nanosheets.
[0033] 2) The dried ZnAl-LDH nanosheets and elemental iodine were mixed at a mass ratio of 1:2, ground evenly, and sealed in a glass bottle. The mixture was heated at 60°C for 6 hours. Then, the iodine-loaded ZnAl-LDH nanosheets and conductive carbon were ultrasonically mixed in ethanol at a mass ratio of 7:3 for 1 hour. The mixture was centrifuged and washed. Finally, the precipitate was dried at 60°C overnight to obtain the ZnAl-LDH@I2 composite material.
[0034] Figure 1 These are scanning electron microscope (SEM) images of the ZnAl-LDH@I2 composite electrode material prepared in Example 1 at different magnifications. It can be seen that many iodine microspheres are loaded between the layered structures.
[0035] Figure 5 This is a charge-discharge curve of the ZnAl-LDH@I2 composite electrode material prepared in Example 1. Figure 6 The graphs show the scaling factor of the ZnAl-LDH@I2 composite electrode material. Both graphs clearly demonstrate a significant improvement in both capacity and stability.
[0036] Comparative Example 1
[0037] Preparation of zinc / aluminum layered bimetallic oxide (ZnAl-LDH): 9 mM zinc nitrate hexahydrate and 3 mM aluminum nitrate nonahydrate were dissolved in 60 mL of deionized water and stirred until completely dissolved. Then, 0.8 M urea was added and stirred until completely dissolved. The mixture was transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene and reacted at 130 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, and the precipitate was collected by centrifugation. The precipitate was washed three times with deionized water and ethanol, and then dried overnight at 60 °C.
[0038] Figure 2 These are scanning electron microscope (SEM) images of the ZnAl-LDH nanosheets prepared in Comparative Example 1 at different magnifications. It can be seen that the three-dimensional interlaced ZnAl-LDH nanosheets without iodine loading possess excellent interlayer structure, which is more conducive to the entry of iodine molecules into their interlayers. This provides an ideal framework for the iodine loading step in Example 1.
[0039] Figure 3The image shows XRD patterns of two materials: ZnAl-LDH@I2 and ZnAl-LDH nanosheets. Both samples exhibit typical Zn-Al LDH diffraction peaks, appearing at 2θ≈11.7, 23.6, and 34.6, respectively, which are consistent with their crystal planes (003), (006), and (012) (JCPDS. 48–1023), indicating the successful synthesis of the materials.
[0040] Figure 4 The images show infrared schematics of two materials: ZnAl-LDH@I2 and ZnAl-LDH nanosheets. Both samples have abundant hydroxyl groups, which can provide ample loading space. The characteristic peaks of carbonate ions prove that the carbonate ions of urea have been inserted into the layers, which also indicates the successful synthesis of the materials.
[0041] Example 2
[0042] Assemble the CR2032 button cell:
[0043] Its overall structure includes: a positive electrode, a separator, an electrolyte (100 μL), and a negative electrode. The main material of the positive electrode is ZnAl-LDH@I2 composite electrode material, a conductive agent (acetylene black), and a binder (PVDF). The mass ratio of ZnAl-LDH@I2 composite electrode material, conductive agent, and binder is 8:1:1. The drying temperature of the coated electrode is 60℃, and the drying time is 8 hours. The loading of the positive electrode is 1 mg. The negative electrode is zinc metal, preferably zinc foil. The separator is glass fiber. The main components of the electrolyte include zinc salt and iodine salt. To avoid the additional influence of anions, a salt solution with the same anion is selected. Preferably, the effective concentration of the electrolyte is 2 mol ZnSO4 + 0.5 mol ZnI2, and the solvent is deionized water.
Claims
1. A method for preparing a zinc / aluminum-rich layered double metal oxide doped with elemental iodine electrode, characterized in that, The preparation method is a two-step preparation method of hydrothermal synthesis and iodine element sublimation, comprising the following steps: 1) Dissolve zinc nitrate hexahydrate and aluminum nitrate nonahydrate in 60 mL of deionized water, then add urea and stir until completely dissolved, then transfer the mixed solution to a stainless steel reaction kettle lined with polytetrafluoroethylene, and place it in an oven for hydrothermal reaction. After the reaction is completed, it is naturally cooled, centrifuged to collect the white precipitate, washed with deionized water and ethanol, and finally the obtained precipitate is dried to obtain ZnAl-LDH nanosheets; 2) Mix the ZnAl-LDH nanosheets and iodine element, grind uniformly, seal in a glass bottle and heat, then mix the iodine-loaded ZnAl-LDH nanosheets with conductive carbon in ethanol by ultrasonic mixing, centrifuge the mixture to obtain a precipitate, and finally dry the obtained precipitate to obtain a ZnAl-LDH@I2 composite electrode material.
2. The production method according to claim 1, characterized by, In step 1), the molar ratio of zinc nitrate hexahydrate to aluminum nitrate nonahydrate is 3:
1.
3. The preparation method according to claim 1, characterized in that, In step 1), the hydrothermal reaction conditions are 130℃ for 24h.
4. The production method according to claim 1, characterized by, In step 2), the ZnAl-LDH nanosheets and iodine element are mixed in a mass ratio of 1:
2.
5. The preparation method according to claim 1, characterized in that, In step 2), the heating conditions are 60℃ for 6 hours.
6. The method of claim 1, wherein, In step 2), the mass ratio of iodine-loaded ZnAl-LDH nanosheets to conductive carbon is 7:
3.
7. The preparation method according to claim 1, characterized in that, In step 2), the ultrasonic mixing time is 1 hour.
8. The method of claim 1, wherein, In steps 1) and 2), the drying conditions are drying at 60℃ overnight.
9. The application of the ZnAl-LDH@I2 composite electrode material prepared by the preparation method of any one of claims 1-8 as a positive electrode in a zinc-iodine battery.
10. Use according to claim 9, characterized in that, The assembly method of the zinc-iodine battery is as follows: ZnAl-LDH@I2 composite electrode material as positive electrode, separator, zinc foil as negative electrode are sequentially loaded into a 2032 size button cell, and electrolyte is added to obtain a battery; the concentration of zinc iodide in the electrolyte is 0.2-0.5mol / L, the concentration of zinc sulfate is 2-2.2mol / L, and the solvent is deionized water; the separator is glass fiber.