A gel electrolyte, its preparation method and use

Abstract

The application discloses a kind of gel electrolyte and its preparation method and application.The gel electrolyte includes polymer gel and the ion liquid gel coated on the surface of the polymer gel;Polymer is selected from at least one in polyacrylamide, polyvinyl alcohol, polyacrylic acid;Ion liquid is selected from at least one in acryloyloxyethyl trimethylammonium chloride, (3-acrylamide propyl) trimethylammonium chloride, 1-vinyl-3-methyl imidazole triflate, 1-vinyl-3-methyl imidazole tetrafluoroborate.Due to the synergistic effect of ion liquid and acrylamide, the multilayer gel electrolyte proposed in the application has higher ion conductivity, the wettability of electrode-electrolyte interface is good, and the growth of zinc dendrite can also be effectively hindered, and the cycle life of battery is improved.

Description

Technical Field

[0001] This application relates to a gel electrolyte, its preparation method, and its application, belonging to the field of electrolyte materials. Background Technology

[0002] The growth of portable electronics, electric vehicles, and renewable energy has fueled a huge demand for high-performance energy storage devices. Lithium-ion batteries (LIBS) have garnered significant attention due to their high energy density and efficiency; however, concerns about their safety stem from the limited availability of lithium resources and the use of organic solvents as electrolytes. In recent years, rechargeable aqueous zinc-ion batteries (ZIBs) have emerged as a promising next-generation alternative energy storage technology due to their abundant resources, environmental friendliness, low cost, and good safety performance.

[0003] Liquid electrolytes face challenges such as leakage, combustion risk, and corrosion associated with organic electrolytes, while all-solid-state electrolytes, due to the presence of Zn... 2+ Its poor diffusion kinetics and low ionic conductivity greatly limit its applications. Summary of the Invention

[0004] Hydrogel electrolytes, prepared by mixing zinc salt solutions with a matrix, can significantly improve electrode interface contact, ionic conductivity, and safety performance. The hydrogel acts as a mechanical barrier and, to some extent, inhibits dendrite growth and mitigates water-induced side reactions. Furthermore, due to their adjustable shape, high flexibility, porous structure, and good mechanical properties, they are commonly used in flexible wearable batteries.

[0005] The purpose of this invention is to provide a multi-level gel electrolyte with a concentration gradient, its preparation method and application. The multi-level gel electrolyte can effectively prevent liquid leakage and dendrite growth in the zinc anode.

[0006] According to one aspect of this application, a gel electrolyte is provided, the gel electrolyte comprising a polymer gel and an ionic liquid gel coated on the surface of the polymer gel;

[0007] The polymer is selected from at least one of polyacrylamide, polyvinyl alcohol, and polyacrylic acid;

[0008] The ionic liquid is selected from at least one of acryloyloxyethyltrimethylammonium chloride, (3-acrylamidopropyl)trimethylammonium chloride, 1-vinyl-3-methylimidazolium trifluoromethanesulfonate, and 1-vinyl-3-methylimidazolium tetrafluoroborate.

[0009] The thickness of the gel electrolyte is 0.5 mm to 1 mm.

[0010] According to another aspect of this application, a method for preparing the above-mentioned gel electrolyte is provided, comprising the following steps:

[0011] (1) An aqueous solution containing polymer monomers, crosslinking agents and initiators is polymerized in a mold to obtain a polymer gel;

[0012] (2) Spray the surface of the polymer gel obtained in (1) sequentially with an aqueous solution of ionic liquid, an aqueous solution of crosslinking agent and an aqueous solution of initiator, and react to obtain the gel electrolyte.

[0013] The polymer monomer is selected from at least one of acrylamide, vinyl alcohol, and acrylic acid;

[0014] The crosslinking agent is selected from at least one of N,N'-methylenebisacrylamide, ethylene glycol diacrylate, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate.

[0015] The initiator is selected from at least one of ammonium persulfate, potassium persulfate, benzoyl peroxide, and tert-butyl hydroperoxide.

[0016] In an aqueous solution containing polymer monomers, crosslinking agents, and initiators, the mass concentration of the polymer monomers is 50–350 mg / ml;

[0017] The mass ratio of the crosslinking agent to the polymer monomer is 0.002:1 to 0.004:1;

[0018] The mass ratio of the initiator to the polymer monomer is 0.002:1 to 0.004:1.

[0019] The polymerization temperature is 70–80°C;

[0020] The polymerization time is 12 to 24 hours.

[0021] Before polymerization, nitrogen gas is introduced into an aqueous solution containing polymer monomers, crosslinking agents, and initiators.

[0022] The nitrogen gas is introduced for 1 to 10 minutes.

[0023] The mass concentration of the ionic liquid aqueous solution is 100–300 mg / ml;

[0024] The volume of the ionic liquid aqueous solution is 1% to 5% of the volume of the aqueous solution containing polymer monomers, crosslinking agents, and initiators;

[0025] The mass concentration of the crosslinking agent aqueous solution is 2-6 mg / ml;

[0026] The volume of the crosslinking agent aqueous solution is 1% to 5% of the volume of the aqueous solution containing polymer monomers, crosslinking agent, and initiator;

[0027] The mass concentration of the initiator aqueous solution is 2–6 mg / ml;

[0028] The volume of the initiator aqueous solution is 1% to 5% of the volume of the aqueous solution containing the polymer monomer, crosslinking agent, and initiator.

[0029] The reaction time is 12–24 hours;

[0030] The reaction temperature is 70–80°C.

[0031] According to another aspect of this application, an aqueous zinc-ion battery is provided, the aqueous zinc-ion battery containing the above-described gel electrolyte.

[0032] Due to the synergistic effect of ionic liquid and acrylamide, the multilayer gel electrolyte proposed in this invention has high ionic conductivity, good wettability at the electrode-electrolyte interface, and can effectively inhibit the growth of zinc dendrites, thereby improving the cycle life of the battery.

[0033] The beneficial effects that this application can produce include:

[0034] (1) The method for preparing multi-level gel electrolyte with concentration gradient proposed in this invention is simple, environmentally friendly, low in cost and safe.

[0035] (2) Because the surface is coated with an ionic liquid gel electrolyte with a concentration gradient, and because it has the characteristics of both ionic liquid and polymer network, its polymer molecular chains are connected or entangled to form a spatial network structure. The structural voids are filled with anions and cations as dispersion media, so the ionic gel has high ionic conductivity.

[0036] (3) The multi-level gel electrolyte with a concentration gradient proposed in this invention avoids concentration polarization caused by anion migration during cycling, and Zn 2+ It can be uniformly deposited / stripped onto the surface without generating zinc dendrites, significantly enhancing the cycle life of aqueous zinc-ion batteries. Attached Figure Description

[0037] Figure 1 The symmetric cycling curves are for the symmetrical cells assembled with multi-level gel electrolytes with concentration gradients prepared in Example 1.

[0038] Figure 2 The image shows a SEM image of the zinc plate after 100 cycles of the multi-level gel electrolyte symmetric battery with concentration gradient prepared in Example 1, at a scale of 1 μm.

[0039] Figure 3 The coulombic efficiency diagram of Zn / Cu assembled with a concentration gradient multi-level gel electrolyte as shown in Example 1.

[0040] Figure 4 Rate plots of the symmetrical cell with concentration gradient multi-level gel electrolyte assembly prepared in Example 1 at different current densities.

[0041] Figure 5 The voltage-current curves are shown for the Zn / Ti battery assembled with a multi-level gel electrolyte and concentration gradient prepared in Example 1. Detailed Implementation

[0042] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0043] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0044] Example 1:

[0045] (1) At 25℃, 7g of acrylamide was completely dissolved in 42mL of deionized water, and then 0.021g of N,N'-methylenebisacrylamide and 0.021g of ammonium persulfate were added sequentially until completely dissolved to obtain a mixed acrylamide solution;

[0046] (2) After passing nitrogen gas through the acrylamide mixed solution prepared in (1), pour it into a mold and heat it at 70℃~80℃ for 12 hours for polymerization.

[0047] (3) Dissolve 0.4g of acryloyloxyethyltrimethylammonium chloride completely in 2mL of deionized water, then add 0.008g of N,N'-methylenebisacrylamide and dissolve it completely before spraying it onto the surface of the polyacrylamide gel prepared in (2) using a spray gun.

[0048] (4) After (3) has been standing for 2 hours, take 0.008 g of ammonium persulfate and dissolve it completely in 2 mL of deionized water. Then, use a spray gun to spray it onto the surface of the gel after it has been standing.

[0049] (5) The gel prepared in (4) was heated and polymerized at 70℃~80℃ for 12 hours to finally obtain a multi-level gel electrolyte with a concentration gradient.

[0050] Figure 1 The symmetrical cycling curves of the symmetrical battery assembled with a multi-level gel electrolyte with a concentration gradient prepared in Example 1 show that the voltage polarization is small and stable during cycling.

[0051] Figure 2The image shows a SEM image of the zinc plate after 100 cycles of the multi-level gel electrolyte symmetric battery with concentration gradient prepared in Example 1, at a scale of 1 μm. The zinc plate surface is smooth after cycling, with less dendrite growth.

[0052] Figure 3 The image shows the coulombic efficiency of the Zn / Cu assembly with a concentration gradient prepared in Example 1. The coulombic efficiency remained stable after 350 cycles.

[0053] Figure 4 The rate capability diagrams of the symmetrical battery assembled with a multi-level gel electrolyte with a concentration gradient prepared in Example 1 at different current densities confirm that the gel electrolyte proposed in this invention has broad application prospects.

[0054] Figure 5 The voltage-current curves are shown for the Zn / Ti battery assembled with a multi-level gel electrolyte and concentration gradient prepared in Example 1.

[0055] Example 2:

[0056] (1) At 25℃, 3g of acrylamide was completely dissolved in 36mL of deionized water, and then 0.009g of N,N'-methylenebisacrylamide and 0.009g of ammonium persulfate were added sequentially until completely dissolved to obtain a mixed acrylamide solution;

[0057] (2) After passing nitrogen gas through the acrylamide mixed solution prepared in (1), pour it into a mold and heat it at 70℃~80℃ for 12 hours for polymerization.

[0058] (3) Dissolve 0.4g of acryloyloxyethyltrimethylammonium chloride completely in 2mL of deionized water, then add 0.008g of N,N'-methylenebisacrylamide and dissolve it completely before spraying it onto the surface of the polyacrylamide gel prepared in (2) using a spray gun.

[0059] (4) After (3) has been standing for 2 hours, take 0.008 g of ammonium persulfate and dissolve it completely in 2 mL of deionized water. Then, use a spray gun to spray it onto the surface of the gel after it has been standing.

[0060] (5) The gel prepared in (4) was heated and polymerized at 70℃~80℃ for 12 hours to finally obtain a multi-level gel electrolyte with a concentration gradient.

[0061] Example 3:

[0062] (1) At 25℃, 14g of acrylamide was completely dissolved in 42mL of deionized water, and then 0.042g of N,N'-methylenebisacrylamide and 0.042g of ammonium persulfate were added sequentially until completely dissolved to obtain a mixed acrylamide solution;

[0063] (2) After passing nitrogen gas through the acrylamide mixed solution prepared in (1), pour it into a mold and heat it at 70℃~80℃ for 12 hours for polymerization.

[0064] (3) Dissolve 0.4g of acryloyloxyethyltrimethylammonium chloride completely in 2mL of deionized water, then add 0.008g of N,N'-methylenebisacrylamide and dissolve it completely before spraying it onto the surface of the polyacrylamide gel prepared in (2) using a spray gun.

[0065] (4) After (3) has been standing for 2 hours, take 0.008 g of ammonium persulfate and dissolve it completely in 2 mL of deionized water. Then, use a spray gun to spray it onto the surface of the gel after it has been standing.

[0066] (5) The gel prepared in (4) was heated and polymerized at 70℃~80℃ for 12 hours to finally obtain a multi-level gel electrolyte with a concentration gradient.

[0067] Example 4:

[0068] (1) At 25℃, 7g of acrylamide was completely dissolved in 42mL of deionized water, and then 0.021g of N,N'-methylenebisacrylamide and 0.021g of ammonium persulfate were added sequentially until completely dissolved to obtain a mixed acrylamide solution;

[0069] (2) After passing nitrogen gas through the acrylamide mixed solution prepared in (1), pour it into a mold and heat it at 70℃~80℃ for 12 hours for polymerization.

[0070] (3) Dissolve 0.2g of acryloyloxyethyltrimethylammonium chloride completely in 2mL of deionized water, then add 0.004g of N,N'-methylenebisacrylamide and dissolve it completely before spraying it onto the surface of the polyacrylamide gel prepared in (2) using a spray gun.

[0071] (4) After (3) has been standing for 2 hours, take 0.004 g of ammonium persulfate and completely dissolve it in 2 mL of deionized water, and spray it onto the gel surface after standing using a spray gun.

[0072] (5) The gel prepared in (4) was heated and polymerized at 70℃~80℃ for 12 hours to finally obtain a multi-level gel electrolyte with a concentration gradient.

[0073] Example 5:

[0074] (1) At 25℃, 7g of acrylamide was completely dissolved in 42mL of deionized water, and then 0.021g of N,N'-methylenebisacrylamide and 0.021g of ammonium persulfate were added sequentially until completely dissolved to obtain a mixed acrylamide solution;

[0075] (2) After passing nitrogen gas through the acrylamide mixed solution prepared in (1), pour it into a mold and heat it at 70℃~80℃ for 12 hours for polymerization.

[0076] (3) Dissolve 0.6g of acryloyloxyethyltrimethylammonium chloride completely in 2mL of deionized water, then add 0.012g of N,N'-methylenebisacrylamide and dissolve it completely before spraying it onto the surface of the polyacrylamide gel prepared in (2) using a spray gun.

[0077] (4) After (3) has been standing for 2 hours, take 0.012g of ammonium persulfate and dissolve it completely in 2mL of deionized water. Then, use a spray gun to spray it onto the surface of the gel after it has been standing.

[0078] (5) The gel prepared in (4) was heated and polymerized at 70℃~80℃ for 12 hours to finally obtain a multi-level gel electrolyte with a concentration gradient.

[0079] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A gel electrolyte, characterized in that, The gel electrolyte includes a polymer gel and an ionic liquid gel coated on the surface of the polymer gel; The polymer is selected from at least one of polyacrylamide, polyvinyl alcohol, and polyacrylic acid; The ionic liquid is selected from at least one of acryloyloxyethyltrimethylammonium chloride, (3-acrylamidopropyl)trimethylammonium chloride, 1-vinyl-3-methylimidazolium trifluoromethanesulfonate, and 1-vinyl-3-methylimidazolium tetrafluoroborate. The preparation method of the gel electrolyte includes the following steps: (1) Polymerize an aqueous solution containing polymer monomers, crosslinking agents and initiators to obtain a polymer gel; (2) Spray the surface of the polymer gel obtained in (1) sequentially with an aqueous solution of an ionic liquid, an aqueous solution of a crosslinking agent, and an aqueous solution of an initiator, and react to obtain the gel electrolyte; The gel electrolyte is used in aqueous zinc-ion batteries.

2. The gel electrolyte according to claim 1, characterized in that, The thickness of the gel electrolyte is 0.5 mm to 1 mm.

3. A method for preparing a gel electrolyte according to any one of claims 1 or 2, characterized in that, Includes the following steps: (1) Polymerize an aqueous solution containing polymer monomers, crosslinking agents and initiators to obtain a polymer gel; (2) Spray the surface of the polymer gel obtained in (1) sequentially with an aqueous solution of ionic liquid, an aqueous solution of crosslinking agent and an aqueous solution of initiator, and react to obtain the gel electrolyte.

4. The preparation method according to claim 3, characterized in that, The polymer monomer is selected from at least one of acrylamide, vinyl alcohol, and acrylic acid; The crosslinking agent is selected from at least one of N,N'-methylenebisacrylamide, ethylene glycol diacrylate, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate; The initiator is selected from at least one of ammonium persulfate, potassium persulfate, benzoyl peroxide, and tert-butyl hydroperoxide.

5. The preparation method according to claim 3, characterized in that, In an aqueous solution containing polymer monomers, crosslinking agents, and initiators, the mass concentration of the polymer monomers is 50~350 mg / ml; The mass ratio of the crosslinking agent to the polymer monomer is 0.002:1 to 0.004:1; The mass ratio of the initiator to the polymer monomer is 0.002:1 to 0.004:

1.

6. The preparation method according to claim 3, characterized in that, The polymerization temperature is 70~80℃; The polymerization time is 12~24h.

7. The preparation method according to claim 3, characterized in that, Before polymerization, nitrogen gas is introduced into an aqueous solution containing polymer monomers, crosslinking agents, and initiators. The nitrogen gas is introduced for 1 to 10 minutes.

8. The preparation method according to claim 3, characterized in that, The mass concentration of the ionic liquid aqueous solution is 100~300 mg / ml; The volume of the ionic liquid aqueous solution is 1% to 5% of the volume of the aqueous solution containing polymer monomers, crosslinking agents, and initiators; The mass concentration of the crosslinking agent aqueous solution is 2~6 mg / ml; The volume of the crosslinking agent aqueous solution is 1% to 5% of the volume of the aqueous solution containing polymer monomers, crosslinking agent, and initiator; The mass concentration of the initiator aqueous solution is 2~6 mg / ml; The volume of the initiator aqueous solution is 1% to 5% of the volume of the aqueous solution containing the polymer monomer, crosslinking agent, and initiator.

9. The preparation method according to claim 3, characterized in that, The reaction time is 12-24 hours; The reaction temperature is 70~80℃.

10. An aqueous zinc-ion battery, characterized in that, The aqueous zinc-ion battery contains the gel electrolyte as described in any one of claims 1 or 2.

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