Electric field-induced self-polymerizing colloid electrolyte, its preparation method and application

Abstract

This invention provides an electric field-induced self-polymerizing colloidal electrolyte, its preparation method, and its application, belonging to the field of battery technology. The electrolyte of this invention consists of a soluble zinc salt, acryloyloxyethyltrimethylammonium chloride, and a solvent. An electric field is applied to the electrolyte during cycling to induce a self-polymerization reaction, yielding a colloidal electrolyte. Acryloyloxyethyltrimethylammonium chloride is used as an additive in the aqueous electrolyte. This monomer can spontaneously generate and polymerize during battery cycling, and under the influence of the electric field, it spontaneously arranges itself on the surface of the zinc electrode, constructing an electrostatic buffer layer at the electrode interface, which facilitates uniform zinc deposition. Furthermore, the polymer segments formed after electropolymerization can transform the aqueous electrolyte into a colloidal system, achieving regulation of the zinc ion solvation structure and suppressing hydrogen evolution and byproducts.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electric field-induced self-polymerizing colloidal electrolyte, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries have rapidly gained dominance in many fields due to their high energy density, mature production technology, and excellent cycle stability. However, lithium-ion batteries are expensive and pose significant safety risks, making the development of green, safe, and high-performance alternatives essential. Against this backdrop, aqueous zinc-ion batteries have emerged as a promising alternative due to their high theoretical capacity (volume specific capacity reaching 5855 mAh cm⁻¹). -3 The specific capacity can reach 820 mAh g. -1 Its advantages, such as high safety and low cost, have made it stand out and attracted widespread attention from scientific research and industry.

[0003] However, aqueous zinc-ion batteries face problems such as dendrite growth, hydrogen evolution corrosion, side reactions, and electrode dissolution. To suppress these side reactions and dendrite growth issues, researchers have proposed many strategies, among which electrolyte regulation strategies centered on additives have received widespread attention. Cationic additives have been chosen as additives for aqueous zinc-ion batteries because they can improve the electric field at the electrode / electrolyte interface and effectively suppress dendrite growth. Chinese patent CN116014265A discloses a high-valence metal cation additive for aqueous zinc-ion batteries and its application (cerium chloride, protactinium bromide, etc.). These high-valence metal cations can generate a denser electric double layer near the zinc anode, constructing a water-poor interface and inducing uniform zinc ion deposition. However, these additives involve rare metals, and most are expensive. Chinese patent CN115101832A discloses a method for introducing cationic additives into the electrolyte of a zinc-ion battery. The additives are one or more of primary amine salt surfactants, secondary amine salt surfactants, tertiary amine salt surfactants, quaternary ammonium salt surfactants, heterocyclic surfactants, onium salt surfactants, and metal cations. When used in aqueous zinc-ion batteries, these additives can suppress hydrogen evolution reaction and zinc dendrite growth to a certain extent. However, most electrolyte additives described in existing patents only play a role in regulating solvation and cannot synergistically regulate the electrolyte-electrode interface, thus having limited effectiveness in suppressing side reactions such as hydrogen evolution. Summary of the Invention

[0004] Based on the above background, this invention proposes an electric field-induced self-polymerizing colloidal electrolyte, its preparation method, and its application. This invention selects a cationic monomer with an olefin C=C structure as an additive component in an aqueous electrolyte. This monomer can self-polymerize during battery cycling and spontaneously arrange itself on the zinc electrode surface under the action of an electric field, constructing an electrostatic buffer layer at the electrode interface, which facilitates uniform zinc deposition. Furthermore, the polymer segments formed after electropolymerization can transform the aqueous electrolyte into a colloidal system, achieving regulation of the zinc ion solvation structure and suppressing hydrogen evolution and byproducts.

[0005] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of the present invention is an electrolyte composed of a soluble zinc salt, acryloyloxyethyltrimethylammonium chloride and a solvent.

[0006] The second technical solution of the present invention is a method for preparing a colloidal electrolyte, wherein an electric field is applied to the above-mentioned electrolyte for cycling to carry out a self-polymerization reaction, thereby obtaining the colloidal electrolyte.

[0007] The third technical solution of the present invention is a colloidal electrolyte prepared by the above preparation method.

[0008] The fourth technical solution of the present invention is the application of the above-mentioned electrolyte or the above-mentioned colloidal electrolyte in an aqueous zinc-ion battery.

[0009] The fifth technical solution of the present invention is an aqueous zinc-ion battery, comprising the above-mentioned electrolyte or the above-mentioned colloidal electrolyte.

[0010] The present invention discloses the following technical effects: (1) In this invention, a mixed solution is prepared by uniformly mixing DAC with zinc sulfate solution. DAC is a cationic monomer that readily gains electrons during battery cycling to form free radical anions DAC. ·- It attacks other DAC monomers, thus polymerizing into PDAC. Therefore, DACs can undergo electronic polymerization during battery cycling without the need for additional initiators.

[0011] (2) The PDAC formed by polymerization promotes the formation of a colloidal system in the solution, regulates the solvation structure of zinc ions, and inhibits hydrogen evolution, corrosion and by-products.

[0012] (3) The PDACs formed by polymerization spontaneously arrange themselves on the electrode surface under the action of electric field. The enriched PDACs repel water molecules at the electrode interface and make the electrode interface uniformly positively charged, which promotes the uniform deposition of zinc and avoids serious dendrite growth problems.

[0013] (4) The PDAC generated during the cycle in the Zn / / MnO2 full cell is spontaneously arranged on the positive electrode, which can effectively suppress the dissolution of the positive electrode active material and enable the full cell to obtain stable cycle performance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a comparison of the infrared spectra of the PDAC colloidal electrolyte formed after cycling in the Zn / / Zn symmetric electrolytic cell in Example 1 of the present invention and the electrolyte of the unpolymerized DAC cationic monomer.

[0016] Figure 2 This is a comparison of the Tyndall effect between the PDAC colloidal electrolyte formed after cycling in the Zn / / Zn symmetric electrolytic cell in Example 1 of the present invention and the electrolyte of the unpolymerized DAC cationic monomer.

[0017] Figure 3 This is an optical photograph of the PDAC enriched at the Zn anode in Embodiment 2 of the present invention.

[0018] Figure 4 In Example 2 of this invention, Zn / / Zn symmetric cells using zinc sulfate electrolyte containing DAC (forming PDAC after cycling) and pure zinc sulfate electrolyte as electrolytes were respectively set at 5 mA cm⁻¹. -2 1 mAh cm -2 XPS spectrum of zinc anode after 5 cycles.

[0019] Figure 5 In Example 3 of this invention, zinc button batteries using pure zinc sulfate electrolyte a and zinc sulfate electrolyte b containing DAC (forming PDAC after cycling) as electrolytes were used at 5 mA cm⁻¹. -2 1 mAh cm -2 SEM image of the zinc anode after 5 cycles.

[0020] Figure 6 In Example 3 of this invention, Zn / / Zn symmetric cells using zinc sulfate electrolyte containing DAC (forming PDAC after cycling) and pure zinc sulfate electrolyte as electrolytes were respectively set at 5 mA cm⁻¹. -2 1 mAh cm -2 XRD pattern of zinc anode after 5 cycles.

[0021] Figure 7 In Example 3 of this invention, zinc sulfate electrolyte containing DAC (forming PDAC after cycling) and pure zinc sulfate electrolyte were used as electrolytes at 1 mA cm⁻¹. -2 1 mAh cm -2 Lower cycle curve graph.

[0022] Figure 8 In Example 4 of this invention, a Zn / / MnO2 full cell was cycled 50 times using a zinc sulfate electrolyte containing DAC (which forms PDAC after cycling) and a pure zinc sulfate electrolyte, respectively. The electrolytes after cycling were then tested by ICP-MS to determine the Mn dissolution in the two electrolyte systems.

[0023] Figure 9 In Example 4 of this invention, Zn / / MnO2 full cells using zinc sulfate electrolyte containing DAC (forming PDAC after cycling) and pure zinc sulfate electrolyte as electrolytes were tested at 1 A g. -1 Performance graph for the next cycle. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] The first aspect of the present invention provides an electrolyte composed of a soluble zinc salt, acryloyloxyethyltrimethylammonium chloride (DAC), and a solvent.

[0030] In a preferred embodiment of the present invention, the concentration of acryloyloxyethyltrimethylammonium chloride in the electrolyte is 0.05~0.3mol / L.

[0031] More preferably, the concentration of acryloyloxyethyltrimethylammonium chloride in the electrolyte is 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.20 mol / L, 0.26 mol / L, or 0.3 mol / L.

[0032] In a preferred embodiment of the present invention, the concentration of soluble zinc salt in the electrolyte is 1-2 mol / L; the solvent is water.

[0033] In a preferred embodiment of the present invention, the soluble zinc salt is zinc sulfate.

[0034] A second aspect of the present invention provides a method for preparing a colloidal electrolyte, wherein an electric field is applied to the above-mentioned electrolyte to induce a self-polymerization reaction, thereby obtaining the colloidal electrolyte.

[0035] The cationic monomer DAC does not require an initiator. During electric field cycling, it can generate a polycationic colloidal electrolyte through a spontaneous reaction that gains electrons. While regulating the zinc ion solvation structure, it forms an electrostatic buffer layer at the electrode interface. After the electric field cycling process, under the action of the electric field, the PDAC spontaneously arranges itself at the electrode interface to form an electrostatic buffer layer, which helps to uniformly deposit zinc and significantly improves the safety, cycle performance and service life of aqueous zinc-ion batteries.

[0036] In a preferred embodiment of the present invention, the electric field cycling is achieved during the charging and discharging process of the zinc-based battery; the zinc-based battery is selected from Zn / / Zn symmetric cells or Zn / / MnO2 full cells.

[0037] In a preferred embodiment of the present invention, when the zinc-based battery is selected from a Zn / / Zn symmetric battery, the cycling current density is 1–20 mA cm⁻¹. -2 1~10 mAh cm -2 The cycle life is 5–20 cycles; when the zinc-based battery is selected from Zn / / MnO2 full cells, the cycle current density is 1–5 A g. -1 The number of cycles is 5 to 50.

[0038] A third aspect of the present invention provides a colloidal electrolyte prepared by the above-described preparation method.

[0039] The fourth aspect of the present invention provides an application of the above-described electrolyte or the above-described colloidal electrolyte in an aqueous zinc-ion battery.

[0040] The fifth aspect of the present invention provides an aqueous zinc-ion battery, comprising the above-described electrolyte or the above-described colloidal electrolyte.

[0041] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0042] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0043] Example 1 (1) Dissolve zinc sulfate in deionized water to prepare a zinc sulfate solution with a concentration of 2 mol / L; (2) Dissolve acryloyloxyethyltrimethylammonium chloride in deionized water to prepare a DAC solution with a concentration of 80wt%; then add the DAC solution to the zinc sulfate solution obtained in step (1) (so that the concentration of DAC in the electrolyte is 0.26mol / L); stir magnetically for 10 min to mix evenly and obtain a uniform and transparent mixed solution, i.e., the electrolyte containing DAC before cycling; (3) Using the electrolyte containing DAC obtained in step (2) as the electrolyte, assemble a Zn / / Zn symmetric electrolytic cell and set it at 5 mAcm -2 1 mAh cm -2 The process was repeated 5 times, and the electrolyte after each cycle was taken as the colloidal electrolyte for electropolymerization to generate PDAC. like Figure 1 As shown, FTIR was measured using the electrolyte that formed PDAC after cycling in step (3) of Example 1 and the DAC electrolyte before cycling. The C=C peak attributable to DAC in the electrolyte sample that formed PDAC was significantly reduced. Figure 2 As shown, the electrolyte that forms PDAC after cycling in step (3) and the electrolyte that forms DAC before cycling were tested to detect the Tyndall effect. The Tyndall effect was obvious in the system with added DAC, which proved that a colloidal system was formed.

[0044] Example 2 Evidence of the enrichment of polycationic electrolytes at the Zn negative electrode: (1) Dissolve zinc sulfate in deionized water to prepare a zinc sulfate solution with a concentration of 2 mol / L; (2) Dissolve acryloyloxyethyltrimethylammonium chloride in deionized water to prepare a DAC solution with a concentration of 80wt%; then add the DAC solution to the zinc sulfate solution obtained in step (1) (so that the concentration of DAC in the electrolyte is 0.26mol / L); stir magnetically for 10 min to mix evenly and obtain a uniform and transparent mixed solution, i.e., the electrolyte containing DAC before cycling; (3) Using the electrolyte containing DAC obtained in step (2) as the electrolyte, assemble a Zn / / Zn symmetric electrolytic cell and set it at 1 mAcm -2 It takes 2 hours to charge.

[0045] like Figure 3 As shown, PDAC enrichment was observed on the zinc anode.

[0046] Using pure zinc sulfate solution (2 mol / L) and the aforementioned electrolyte containing DAC as electrolytes, and zinc foil with a thickness of 0.1 mm and a diameter of 14 mm as electrodes, Zn / / Zn coin cells were assembled, with a current of 5 mA cm⁻¹. -2 1 mAh cm -2 After five cycles, the zinc-deposited side electrodes of the two systems were collected and compared using XPS testing.

[0047] like Figure 4 As shown, the N 1s peak appears at the interface of the system that forms PDAC colloid after cycling, proving that the PDAC is arranged at the zinc electrode interface.

[0048] Example 3 Dendrite growth, byproducts, and cycle performance test results in a self-polymerizing colloidal electrolyte system: Using pure zinc sulfate solution (2 mol / L) and the DAC-containing electrolyte prepared in Example 2 as electrolytes, and zinc foil with a thickness of 0.1 mm and a diameter of 14 mm as electrodes, Zn / / Zn coin cells were assembled, with a current of 5 mA cm⁻¹. -2 1 mAh cm -2 After 5 cycles, the zinc electrode from both systems was collected and subjected to SEM (Sequencing). Figure 5 XRD Figure 6 Test comparison. SEM images show that the zinc deposition in the PDAC colloidal system is more uniform; XRD patterns show that byproducts at 8.4 °C are almost invisible on the zinc electrode in the PDAC colloidal system. Zn / / Zn coin cells with the two electrolyte systems were compared at 1 mA cm⁻¹. -2 1 mAh cm -2 Cyclic performance testing showed that symmetrical cells in the system that formed PDAC gel after cycling exhibited superior cycle performance. Figure 7 ).

[0049] Example 4 Pure zinc sulfate solution (as a comparison) and the electrolyte containing the cationic monomer DAC prepared in Example 2 were used as electrolytes, respectively. A zinc foil with a thickness of 0.1 mm and a diameter of 14 mm was used as the negative electrode, carbon cloth as the substrate, and MnO2 as the positive electrode material. The positive electrode material loading was 1~2.5 mg / cm³. -2The button cell assembly is completed. The electrolyte, which forms a PDAC colloidal system after 50 cycles, further inhibits MnO2 dissolution. Figure 8 (ICP-MS testing). Furthermore, the Zn / / MnO2 full cell forming the PDAC colloidal electrolyte retained over 80% of its capacity after 1000 cycles, while the capacity retention of pure zinc sulfate electrolyte was only about 50% after 400 cycles. Figure 9 ).

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electrolyte, characterized by, It consists of a soluble zinc salt, acryloyloxyethyltrimethylammonium chloride, and a solvent.

2. The electrolyte according to claim 1, characterized in that, The concentration of acryloyloxyethyltrimethylammonium chloride in the electrolyte is 0.05~0.3 mol / L.

3. The electrolyte of claim 1, wherein The concentration of soluble zinc salt in the electrolyte is 1–2 mol / L; the solvent is water.

4. A method for producing a colloid electrolyte, characterized by, An electric field is applied to the electrolyte of claim 1 and circulated to induce a self-polymerization reaction, thereby obtaining the colloidal electrolyte.

5. The preparation method according to claim 4, characterized in that, The electric field cycle is achieved during the charging and discharging process of the zinc-based battery; the zinc-based battery is selected from Zn / / Zn symmetric cells or Zn / / MnO2 full cells.

6. The production method according to claim 5, characterized by, When the zinc-based battery is selected from a Zn / / Zn symmetric battery, the cycle current density is 1-20 mA cm -2 , 1-10 mAh cm -2 , and the cycle number is 5-20 times; when the zinc-based battery is selected from a Zn / / MnO2 full battery, the cycle current density is 1-5 A g -1 , and the cycle number is 5-50 times.

7. The colloidal electrolyte prepared by the method described in claim 4.

8. The application of the electrolyte as described in claim 1 or the colloidal electrolyte as described in claim 7 in an aqueous zinc-ion battery.

9. An aqueous zinc-ion battery, characterized in that, Includes the electrolyte as described in claim 1 or the colloidal electrolyte as described in claim 7.

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