Zinc ion battery electrolyte and zinc metal negative electrode passivation layer constructed by same
By adding thiodiic acid additives to zinc ion electrolytes, a passivation layer with toughness and self-healing ability is constructed, which solves the problems of easy cracking of the passivation layer and uncontrollable metal deposition in aqueous zinc metal batteries, extends battery life and supports high-reliability energy storage applications.
Patent Information
- Application Number
- CN202511758989.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-02-06
AI Technical Summary
The passivation layer of existing aqueous zinc metal batteries is sensitive to electrode surface defects and is prone to cracking. Furthermore, the metal deposition behavior is uncontrollable, leading to short circuits and shortened cycle life.
Thiodi acid additives are added to zinc ion electrolyte to form a passivation layer composed of organic molecules. Through chemical reaction, a tough and self-healing passivation layer is generated to adapt to changes in the electrode surface.
It achieves high tolerance and self-healing capability for electrode surface defects, extends battery life, and supports energy storage applications with high reliability and high continuity.
Smart Images
Figure CN121484239A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of batteries, and more specifically to a zinc-ion battery electrolyte and a zinc metal negative electrode passivation layer constructed therefrom. Background Technology
[0002] Aqueous zinc metal batteries are expected to become a new type of energy storage device that can be widely used due to their advantages such as large theoretical capacity, multi-electron redox reaction, relatively low equilibrium potential, good stability to water / air, low cost, and environmental friendliness.
[0003] Because the electrochemical potential of zinc metal (-0.76 V vs. standard hydrogen electrode) is lower than the hydrogen evolution potential of commonly used aqueous electrolytes (2MZnSO4, ZnCl2, etc.), the electrolyte and electrode react continuously, resulting in severe self-discharge. Furthermore, the metal deposition behavior is highly uncontrollable, with severe dendrite growth leading to short circuits and significantly shortening the battery's cycle life.
[0004] The formation of traditional passivation layers is an electrochemical process driven by the energy difference between the LUMO of the electrolyte and the HOMO of the electrode, which is highly sensitive to the inhomogeneity of the chemical potential on the electrode surface (such as defects). Traditional passivation layers are mostly inorganic materials, but the rigidity of inorganic materials makes them lack toughness and have poor deformation ability. Moreover, they have strong adhesion to the electrode surface, making them prone to cracking when the electrode volume changes drastically. Summary of the Invention
[0005] To address the problems of existing passivation layer construction methods for aqueous zinc metal batteries, such as sensitivity to electrode surface defects and susceptibility to cracking with changes in electrode volume, this invention proposes a zinc-ion battery electrolyte and a zinc metal negative electrode passivation layer constructed therefrom. The specific technical solution is as follows: A zinc-ion battery electrolyte includes a reference electrolyte and a thiodiic acid additive; The reference electrolyte is selected from any one or more of zinc sulfate, zinc bromide, zinc nitrate, zinc chloride, zinc perchlorate, zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonylimide) zinc salt and zinc acetate, and prepared in any proportion; The thiodicarboxylic acid additive is 3,3'-thiodipropionic acid or 3,3'-dithiodipropionic acid.
[0006] Furthermore, the concentration of the reference electrolyte is 0.1-12M.
[0007] Furthermore, the amount of the thiodic acid additive added to the reference electrolyte satisfies the following condition: the thiodic acid additive reaches a saturation concentration in the reference electrolyte.
[0008] A zinc metal negative electrode passivation layer constructed from zinc-ion battery electrolyte.
[0009] A method for constructing a zinc metal anode passivation layer using a zinc-ion battery electrolyte includes: The zinc metal electrode is immersed in the electrolyte of the zinc-ion battery to obtain a uniformly covered passivation layer on the surface of the zinc metal electrode. or, Zinc metal batteries are assembled using the zinc-ion battery electrolyte and cycled to form a passivation layer on the surface of the zinc metal electrode. Alternatively, the zinc-ion battery electrolyte can be injected into a working zinc metal battery to obtain a passivation layer on the surface of the zinc metal electrode.
[0010] The beneficial effects of this invention are as follows: 1. The passivation layer constructed from the zinc-ion battery electrolyte of this invention exhibits high defect tolerance and self-healing capabilities. The passivation layer is composed of organic molecules and organic compounds derived from electrolyte additives, possessing a certain degree of toughness. The main components of the passivation layer are generated through a chemical (distinct from electrochemical) reaction between the electrolyte additives and the electrode. The generation process of the passivation layer is largely unaffected by the chemical potential of the electrode surface and exhibits a clear interface with the electrode. These characteristics make the passivation layer less prone to breakage during drastic expansion of the electrode volume.
[0011] 2. The passivation layer constructed from the zinc-ion battery electrolyte of the present invention is compatible with metal electrodes with many surface processing defects and large volume changes during cycling, thereby achieving long-term protection of the zinc metal electrode and extending the battery's service life.
[0012] 3. The passivation layer constructed by the zinc-ion battery electrolyte of the present invention can be constructed by injecting zinc-ion electrolyte into the zinc-ion battery without interrupting battery operation, and can be used in high-reliability and high-continuity energy storage application scenarios.
[0013] 4. The zinc-ion battery electrolyte, passivation layer, and their construction method of the present invention use inexpensive raw materials, have a simple technical route, and can be applied on a large scale. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a zinc metal electrode with a passivation layer on its surface, obtained by immersing a zinc metal electrode in a zinc-ion battery electrolyte for 24 hours or more. Figure 1 The right image is a magnified view of a portion of the left image.
[0015] Figure 2 X-ray diffraction patterns and structural formulas of organic molecules.
[0016] Figure 3A schematic diagram showing the formation of a passivation layer approximately 400 nm thick on the electrode surface after three or more cycles of a zinc metal symmetric battery assembled using an electrolyte containing additives.
[0017] Figure 4 for Figure 3 The energy spectrum of the passivation layer.
[0018] Figure 5 X-ray diffraction patterns of electrode surfaces after the battery has been cycled three times or more, in order to assemble a zinc metal symmetric cell using an electrolyte containing additives. Figure 6 Photograph of a Swagelok molded battery used for electrolyte injection.
[0019] Figure 7 Charge-discharge cycle curves of zinc-ion symmetric batteries that have been operating for a period of time using a reference electrolyte and are about to fail, obtained by injecting zinc-ion electrolyte.
[0020] Figure 8 Comparison of photographs and scanning electron microscope images of a scratched zinc metal electrode after cycling in a standard electrolyte and a zinc ion electrolyte, respectively.
[0021] Figure 9 The constant current charge-discharge curves of the zinc-ion symmetric battery are shown when using a reference electrolyte and a zinc-ion electrolyte, respectively.
[0022] Figure 10 The graph shows the changes in energy density and coulombic efficiency of zinc-ion full cells with charge-discharge cycles when using a reference electrolyte and a zinc-ion electrolyte, respectively. Detailed Implementation
[0023] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become clearer. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.
[0024] Example 1 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of a 2 M zinc chloride solution; Add 0.267 g of 3'3-thiodipropionic acid to a zinc chloride solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc sulfate solution and just reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0025] A passivated zinc metal electrode was obtained by immersing it in a zinc ion electrolyte for 3 days. Figure 1 As shown. Figure 1The right image is a magnified view of a portion of the left image. It can be seen from the right image that there is a uniformly covered passivation layer on the surface of the zinc metal electrode.
[0026] The main component of this passivation layer is considered to be an organic molecule, and its X-ray diffraction pattern and structural formula are as follows: Figure 2 As shown.
[0027] Example 2 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of a 2 M zinc chloride solution; Add 0.267 g of 3'3-thiodipropionic acid to a zinc chloride solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc chloride solution and just reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0028] Zinc foil is placed inside the positive electrode shell, followed by the separator, zinc ion electrolyte, zinc foil, stainless steel gasket, and negative electrode shell. The assembled battery is then pressed and sealed in a static pressure machine to obtain a zinc-ion symmetrical battery.
[0029] Zinc-ion batteries at 0.2 mA cm⁻¹ -2 - 0.2 mAh cm -2 Under normal operating conditions, it is charged and discharged 10 times.
[0030] After disassembling the zinc-ion battery in operation, a passivated zinc metal electrode was obtained. The cross-section of the passivated zinc metal electrode was observed using a scanning electron microscope, as shown below. Figure 3 As shown. The energy spectrum of the same region is as follows. Figure 4 As shown. From Figure 2 As shown in Figure (a), a dense passivation layer with a thickness of approximately 400 nm has formed on the surface of the zinc metal electrode. From... Figure 4 It can be seen that the passivation layer is composed of zinc, oxygen, sulfur and carbon elements, and the elements are evenly distributed along the passivation layer.
[0031] The main components of this passivation layer are considered to be the same as those in Example 1, and its X-ray diffraction pattern is as follows: Figure 5 As shown.
[0032] Example 3 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of 2 M zinc chloride solution; Add 0.267 g of 3'3-thiodipropionic acid to a zinc chloride solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc sulfate solution and just reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0033] Use such as Figure 6The Swagelok mold, zinc foil, glass fiber diaphragm, and 60 μL of reference electrolyte shown are used to assemble a zinc-ion symmetric battery.
[0034] Zinc-ion symmetric cells at 2 mA cm -2 - 2 mAh cm -2 Under operating conditions, charge and discharge the battery until the battery voltage fluctuates significantly (~60 hours). At this point, inject 20 microliters of zinc ion electrolyte into the zinc ion battery through the top opening of the Swagelok mold battery.
[0035] like Figure 7 As shown, after the zinc ion electrolyte was injected, the working voltage of the zinc ion battery returned to stability and continued to work for 900 hours, indicating that the zinc ion electrolyte can form a passivation layer in situ during battery operation, thus extending the electrode cycle life.
[0036] Example 4 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of 2 M zinc chloride solution; Add 0.267 g of 3'3-thiodipropionic acid to a zinc chloride solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc chloride solution and just reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0037] A 20-micrometer-wide cross-shaped scratch is made on a 50-micrometer-thick zinc foil using a blade, which is used as a zinc metal electrode with surface defects.
[0038] A scratched zinc foil is placed inside the positive electrode shell, followed by the separator, zinc ion electrolyte, scratched zinc foil, stainless steel gasket, and negative electrode shell. The assembled battery is then pressed and sealed in a static pressure machine to obtain a zinc-ion symmetrical battery.
[0039] Example 5 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of 2 M zinc sulfate solution; Add 0.134 g of 3'3-thiodipropionic acid to a zinc sulfate solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc sulfate solution and reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0040] Zinc foil is placed inside the positive electrode shell, followed by the separator, zinc ion electrolyte, zinc foil, stainless steel gasket, and negative electrode shell. The assembled battery is then pressed and sealed in a static pressure machine to obtain a zinc-ion symmetrical battery.
[0041] Example 6 The only difference between Example 6 and Example 5 is that the reference electrolyte is a zinc bromide electrolyte with a concentration of 0.1 M.
[0042] Example 7 The only difference between Example 7 and Example 5 is that the reference electrolyte is a zinc nitrate electrolyte with a concentration of 0.1 M.
[0043] Example 8 The only difference between Example 8 and Example 5 is that the reference electrolyte is a zinc perchlorate electrolyte with a concentration of 0.1 M.
[0044] Example 9 The only difference between Example 9 and Example 5 is that the reference electrolyte is a zinc trifluoromethanesulfonate electrolyte with a concentration of 0.1 M.
[0045] Example 10 The only difference between Example 10 and Example 5 is that the reference electrolyte is a 0.1 M bis(trifluoromethanesulfonyl) zinc electrolyte.
[0046] Example 11 The only difference between Example 11 and Example 5 is that the reference electrolyte is a zinc acetate electrolyte with a concentration of 0.1 M.
[0047] Example 12 The only difference between Example 12 and Example 5 is that the reference electrolyte is a zinc chloride electrolyte with a concentration of 12 M.
[0048] Example 13 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of 2 M zinc chloride solution; Add 0.02 g of 3'3-dithiodipropionic acid to the zinc chloride electrolyte and stir continuously until the 3'3-dithiodipropionic acid is completely dissolved in the zinc sulfate solution and just reaches the saturation concentration of 3'3-dithiodipropionic acid in the zinc sulfate solution, thus obtaining the zinc ion electrolyte.
[0049] Zinc foil is placed inside the positive electrode shell, followed by the separator, zinc ion electrolyte, zinc foil, stainless steel gasket, and negative electrode shell. The assembled battery is then pressed and sealed in a static pressure machine to obtain a zinc-ion symmetrical battery.
[0050] Example 14 Preparation of standard electrolyte: Deionized water was selected as the solvent to prepare 10 ml of 2 M zinc chloride solution; Add 0.267 g of 3'3-thiodipropionic acid to a zinc chloride solution and stir continuously until the 3'3-thiodipropionic acid is completely dissolved in the zinc chloride solution and just reaches the saturation concentration of 3'3-thiodipropionic acid in the zinc sulfate solution, thus obtaining a zinc ion electrolyte.
[0051] Preparation of V2O5 positive electrode: Polyvinylidene fluoride powder was completely dissolved in N-methylpyrrolidone at a concentration of 50 mg / ml. V2O5 powder, acetylene black, and polyvinylidene fluoride solution were mixed at a mass ratio of 7:2:1 to form a slurry, which was then uniformly coated onto the surface of a titanium mesh and dried in an oven at 80°C for 12 hours to prepare the V2O5 positive electrode.
[0052] A V₂O₅ positive electrode sheet is placed inside the positive electrode shell, followed by a separator, zinc-ion electrolyte, zinc foil, a stainless steel gasket, and a negative electrode shell. The assembled battery is then pressed and sealed in a static pressure machine to obtain a zinc-ion full cell.
[0053] Comparative Example 1 This example provides a method for preparing an aqueous zinc-ion battery, the steps of which are basically the same as those in Example 4, except that a standard electrolyte is used.
[0054] Comparative Example 2 This example provides a method for preparing an aqueous zinc-ion battery, the steps of which are basically the same as those in Example 5, except that a reference electrolyte is used.
[0055] Comparative Example 3 This example provides a method for preparing an aqueous zinc-ion battery, the steps of which are basically the same as those in Example 14, except that a reference electrolyte is used.
[0056] The zinc-ion batteries from Example 4 and Comparative Example 1 were tested at 1 mA cm⁻¹. -2 -1 mAh cm -2 Under the conditions of charge and discharge 10 times. For example... Figure 8 As shown in Figure (a) of Comparative Example 1, obvious scratches can be observed in both the front and back photographs of the zinc metal electrode after cycling. Scanning electron microscopy images reveal uneven zinc deposition, mainly concentrated at the edges of the scratches, where significant pitting corrosion occurs. Figure 8 As shown in Figure (b), scratches are visible in the back photograph of the electrode after cycling in Example 4, but are almost invisible in the front photograph. In the scanning electron microscope image, the zinc deposition is uniformly distributed, and the scratches have become less noticeable, indicating that the presence of the passivation layer improves the tolerance of the zinc metal electrode to electrode surface defects.
[0057] The zinc-ion batteries from Example 5 and Comparative Example 2 were tested at 2 mA cm⁻¹. -2 -2 mAh cm -2 Under the conditions of charging and discharging, such as... Figure 9As shown, the zinc-ion battery in Comparative Example 2 can only cycle for about 110 hours, while the zinc-ion battery in Example 5 can cycle stably for more than 2100 hours, with a cycle life 20 times that of the zinc-ion battery in Comparative Example 2.
[0058] The zinc-ion full cells from Example 14 and Comparative Example 3 were tested at room temperature and 5 A g. -1 Under certain conditions, charging and discharging are performed. For example... Figure 10 As shown, the zinc-ion full cell in Comparative Example 3 exhibited a continuously decreasing capacity and unstable coulombic efficiency (see ZnCl2), while the zinc-ion full cell in Example 14 retained over 90% of its capacity and maintained a stable coulombic efficiency after 2000 cycles. This demonstrates that the electrolyte additives and passivation layer continuously play a role during battery cycling, thereby promoting stable battery capacity.
[0059] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.
Claims
1. A zinc-ion battery electrolyte, characterized in that, Includes a reference electrolyte and thiodiic acid additives; The reference electrolyte is selected from any one or more of zinc sulfate, zinc bromide, zinc nitrate, zinc chloride, zinc perchlorate, zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonylimide) zinc salt and zinc acetate, and prepared in any proportion; The thiodicarboxylic acid additive is 3,3'-thiodipropionic acid or 3,3'-dithiodipropionic acid.
2. The zinc-ion battery electrolyte according to claim 1, characterized in that, The concentration of the reference electrolyte is 0.1-12M.
3. The zinc-ion battery electrolyte according to claim 1, characterized in that, The amount of the thiodic acid additive added to the reference electrolyte is such that the thiodic acid additive reaches a saturation concentration in the reference electrolyte.
4. A zinc metal negative electrode passivation layer constructed from the zinc-ion battery electrolyte according to any one of claims 1 to 3.
5. A method for constructing a zinc metal negative electrode passivation layer using the zinc-ion battery electrolyte according to any one of claims 1 to 3, characterized in that, include: The zinc metal electrode is immersed in the electrolyte of the zinc-ion battery to obtain a uniformly covered passivation layer on the surface of the zinc metal electrode. or, Zinc metal batteries are assembled using the zinc-ion battery electrolyte and cycled to form a passivation layer on the surface of the zinc metal electrode. Alternatively, the zinc-ion battery electrolyte can be injected into a working zinc metal battery to obtain a passivation layer on the surface of the zinc metal electrode.