A method for preparing an inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries
By combining polymer double crosslinking and clay mineral materials, an inorganic composite hydrogel electrolyte with an interpenetrating network structure is formed, which solves the problems of zinc dendrites and interfacial side reactions in zinc-ion batteries, improves the stability and mechanical properties of the battery, and is suitable for flexible wearable devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEBEI UNIV OF TECH
- Filing Date
- 2023-06-12
- Publication Date
- 2026-07-17
AI Technical Summary
Existing aqueous zinc-ion batteries suffer from zinc dendrite growth and electrode/electrolyte interface side reactions, leading to reduced coulombic efficiency and safety hazards. Furthermore, the mechanical and electrochemical properties of existing hydrogel electrolytes are insufficient.
Inorganic composite hydrogel electrolytes were prepared by using polymer double crosslinking technology and clay mineral materials as inorganic fillers to form an interpenetrating double crosslinking network, thereby increasing the density of the gel network and ion transport channels.
It improves the mechanical and electrochemical properties of hydrogel electrolytes, effectively inhibits zinc dendrite growth, and enhances battery stability and safety, making it suitable for flexible wearable devices.
Smart Images
Figure CN116742157B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aqueous zinc-ion battery gel electrolyte preparation technology, specifically relating to a method for preparing an inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries. Background Technology
[0002] Aqueous zinc-ion batteries have attracted much attention due to their advantages such as low cost, high safety, high power density, and environmental friendliness. However, in liquid electrolytes, batteries face problems such as zinc dendrite growth and electrode / electrolyte interface side reactions during charge-discharge cycles, leading to reduced coulombic efficiency, affecting battery life, and the gases generated by side reactions may further pose safety hazards.
[0003] Hydrogel electrolytes are a special type of electrolyte with a state between solid and liquid, possessing excellent ionic conductivity, good mechanical properties, and superior water absorption and retention capabilities. Compared to liquid electrolytes, hydrogel electrolytes can improve the zinc anode surface / interface, regulate interfacial ion transport, and effectively solve zinc anode problems such as zinc dendrite formation and interfacial side reactions. Furthermore, hydrogel electrolytes have water retention capacity and certain mechanical properties, effectively preventing electrolyte leakage that occurs in liquid electrolyte systems, and exhibiting stability under stretching and bending conditions, thus enhancing the application prospects of zinc-ion batteries in flexible batteries. Currently, there are numerous research reports on hydrogel electrolytes prepared from polyvinyl alcohol, polyacrylonitrile, polyacrylamide, polyethylene oxide, xanthan gum, and gelatin, but these generally suffer from poor mechanical and electrochemical properties. Therefore, designing and developing a hydrogel electrolyte with excellent electrochemical performance, superior mechanical properties, and environmental friendliness is of great significance.
[0004] Chinese patent CN115172904A discloses a polyvinyl alcohol-based hydrogel electrolyte and its preparation method. The method involves dissolving polyvinyl alcohol in a phytic acid aqueous solution by heating, preparing a hydrogel, and then immersing the hydrogel in an electrolyte solution to obtain the corresponding hydrogel electrolyte. The obtained electrolyte exhibits good mechanical properties and the ability to suppress zinc dendrites. However, the preparation method disclosed in the patent is relatively complex, and the conductivity and cycle stability of the prepared hydrogel can be further improved.
[0005] To address the above problems, this invention provides a hydrogel electrolyte utilizing polymer double crosslinking and clay mineral materials as inorganic fillers. The polymer double crosslinking structure effectively enhances molecular interactions and stabilizes the gel structure. Simultaneously, the clay minerals, primarily composed of aluminum and magnesium, are hydrous silicate minerals with natural nanostructures, exhibiting excellent adsorption and ion exchange capabilities. The addition of clay mineral materials increases the number of inorganic crosslinking points, resulting in a denser gel network distribution and providing more ion transport channels, effectively improving the electrochemical performance of zinc-ion batteries. This method is simple, easy to control, and can prepare inorganic composite hydrogel electrolytes with excellent electrochemical performance, superior mechanical properties, and high stability. Summary of the Invention
[0006] The purpose of this invention is to address the technical challenges in preparing gel electrolytes for aqueous zinc-ion batteries by providing a method for preparing an inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries. This method utilizes in-situ polymerization of polymer monomers to form an interpenetrating double cross-linked network, which improves the mechanical properties and stability of the hydrogel electrolyte. The addition of clay minerals to the hydrogel system further enhances its mechanical properties, and the inclusion of clay minerals increases ion migration channels within the hydrogel, guiding the migration of zinc ions. This invention yields an inorganic composite hydrogel electrolyte with excellent electrochemical performance, superior mechanical properties, and high stability, effectively solving problems such as dendrite formation and corrosion in zinc metal anodes.
[0007] The technical solution of this invention is as follows:
[0008] A method for preparing an inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries includes the following steps:
[0009] (1) Add polyvinyl alcohol and clay mineral materials to deionized water and mix with ultrasound for 5-60 min, then heat and stir at 60-95℃ to dissolve and obtain a composite solution;
[0010] The mass ratio of polyvinyl alcohol to deionized water is 1:5 to 1:30; the mass ratio of polyvinyl alcohol to clay mineral material is 100:1 to 1:1.
[0011] The clay mineral material is one or more of zinc-based montmorillonite, talc, kaolinite, attapulgite, and halloysite;
[0012] (2) Add an initiator and a crosslinking agent to the composite solution obtained in step 1), stir and dissolve at 20-60°C for 10-60 min to obtain a mixed solution; add polymer monomers to the mixed solution obtained above, stir thoroughly at 20-45°C, allow to stand at 50-80°C for 0.5-10 h for crosslinking, then freeze at -10--30°C for 5-15 h, and then thaw to obtain a hydrogel;
[0013] Wherein, the mass ratio of the initiator to the polymer monomer is 1:50 to 1:200; the mass ratio of the crosslinking agent to the polymer monomer is 1:500 to 1:2000; and the mass ratio of the polymer monomer to polyvinyl alcohol is 1:5 to 5:1.
[0014] The crosslinking agent is one or more of glutaraldehyde, dienylphenol, and N,N'-methylenebisacrylamide;
[0015] The initiator is one or more of potassium persulfate, ammonium persulfate, and benzoyl peroxide.
[0016] The polymer monomers are one or more of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and acrylic acid.
[0017] (3) Immerse the hydrogel in a zinc salt aqueous solution for 0.5 to 5 days to obtain an inorganic composite hydrogel electrolyte;
[0018] The concentration of the zinc salt aqueous solution is 0.5–5 mol / L.
[0019] The zinc salt is one or more of zinc sulfate, zinc chloride, and zinc trifluoromethanesulfonate;
[0020] The beneficial effects of this invention are as follows:
[0021] 1. This invention provides a novel method for preparing inorganic composite hydrogel electrolytes for aqueous zinc-ion batteries, which utilizes polymer double cross-linking and employs clay mineral materials as inorganic fillers.
[0022] 2. This invention employs a polymer dual crosslinking system. Compared to monomer crosslinking, this system can form a more uniform dual crosslinked interpenetrating network. The in-situ polymerization of polymer monomers in polyvinyl alcohol solution allows the two polymer networks to interpenetrate, resulting in a synergistic effect that improves the overall mechanical strength of the gel. The interaction of hydrogen bonds gives it a more stable three-dimensional network structure, which can more effectively absorb electrolyte. This improves the phenomenon of polymer degradation and electrolyte release during long-term use of single crosslinked hydrogel electrolytes to a certain extent, greatly enhancing the stability of the hydrogel electrolyte.
[0023] 3. This invention uses clay minerals as inorganic fillers to increase inorganic cross-linking points, resulting in a denser gel network. The unique structure of clay minerals provides more ion transport channels. In experiments, the inorganic hydrogel electrolyte of this invention exhibits a high ionic conductivity of 47.6 mS / cm, and the Zn / / Zn symmetric cell assembled using it can achieve a maximum cycle time of 2400 h. SEM analysis of the zinc foil surface after cycling the Zn / / Zn symmetric cell revealed that the hydrogel electrolyte effectively inhibited the growth of zinc dendrites. Simultaneously, the hydrogel electrolyte of this invention can achieve an elongation of 543%, effectively improving the mechanical properties of the gel. Attached Figure Description
[0024] Figure 1 Here is a SEM image of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte from Example 1;
[0025] Figure 2 The infrared spectrum image of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte of Example 1;
[0026] Figure 3 Symmetric battery cycle stability of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte of Example 1;
[0027] Figure 4 SEM images of the electrode surface of the symmetrical battery of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte in Example 1 after 50 cycles.
[0028] Figure 5 The mechanical properties of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte in Example 1;
[0029] Figure 6 SEM image of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte of Example 2;
[0030] Figure 7 The symmetric battery cycle stability of the polyvinyl alcohol-acrylamide-montmorillonite hydrogel electrolyte in Example 2; Detailed Implementation
[0031] The following examples are intended to further illustrate the present invention, but not to limit it.
[0032] Example 1:
[0033] The first step is to heat and dissolve polyvinyl alcohol in deionized water and then ultrasonically mix it with clay mineral materials. The specific steps are as follows:
[0034] Take 1g of polyvinyl alcohol and 0.1g of zinc-based montmorillonite and place them in 20mL of deionized water. Sonicate for 20 minutes to disperse them, and then heat and stir at 90℃ for 2 hours until the polyvinyl alcohol is completely dissolved in the deionized water.
[0035] The second step is the addition of the initiator and cross-linking agent and the preparation of the gel, the specific steps of which are as follows:
[0036] Add 2 mg of N,N'-methylenebisacrylamide and 15 mg of potassium persulfate to the composite solution obtained in step 1), and stir to dissolve at 40 °C for 30 min. Then add 2 g of acrylamide and stir at 40 °C for 2 h. Pour the mixture into a mold and seal it, then crosslink at 60 °C for 4 h. After freezing at -20 °C for 12 h, remove and thaw to demold, obtaining the hydrogel.
[0037] Step 3:
[0038] The above hydrogel was immersed in a 2 mol / L zinc sulfate aqueous solution for 2 days to allow it to fully swell and absorb the electrolyte, thus obtaining a mechanical composite hydrogel electrolyte.
[0039] The morphology of the sample was observed using a JEOL 7610F scanning electron microscope from Japan, revealing a uniform distribution of gel pore size. Figure 1 The gel structure was analyzed using Fourier transform infrared spectroscopy, and the results are as follows: Figure 2 As shown, the two polymers form a double cross-linked network through hydrogen bonding, with zinc-based montmorillonite mechanically doped into it. The prepared hydrogel electrolyte was used in a Zn / / Zn symmetric battery (model C2016), exhibiting better cycle stability compared to aqueous electrolytes. Testing was conducted using a Newway battery testing system at 0.5 mA cm⁻¹. -2 At a current density of 0.5 mAh cm⁻¹ -2 At its surface capacity, it can stably cycle for 2400 hours. Figure 3 The morphology of the zinc electrode surface after 50 cycles of a symmetrical cell was observed using a JEOL 7610F scanning electron microscope (SEM). Figure 4 The pure zinc electrode surface is smooth and the deposition is uniform. Mechanical tests were performed on the prepared gel, such as... Figure 5 As shown, with an initial length of 3.5 cm and an initial width of 0.5 mm, the gel's elongation reached 22.5 cm before breaking, an increase of 543%.
[0040] Example 2:
[0041] The first step is to heat and dissolve polyvinyl alcohol in deionized water and then ultrasonically mix it with clay mineral materials. The specific steps are as follows:
[0042] Take 1g of polyvinyl alcohol and 0.2g of zinc-based montmorillonite and place them in 20mL of deionized water. Sonicate for 20 minutes to disperse them, and then heat and stir at 90℃ for 2 hours until the polyvinyl alcohol is completely dissolved in the deionized water.
[0043] The second step is the addition of the initiator and cross-linking agent and the preparation of the gel, the specific steps of which are as follows:
[0044] Add 2 mg of N,N'-methylenebisacrylamide and 15 mg of potassium persulfate to the composite solution obtained in step 1), and stir to dissolve at 40 °C for 30 min. Then add 2 g of acrylamide and stir at 40 °C for 2 h. Pour the mixture into a mold and seal it, then crosslink at 60 °C for 4 h. After freezing at -20 °C for 12 h, remove and thaw to demold, obtaining the hydrogel.
[0045] The third step is to immerse the hydrogel in a zinc salt aqueous solution to allow it to fully swell and absorb, thus obtaining an inorganic composite hydrogel electrolyte. The specific steps are as follows:
[0046] The above hydrogel was immersed in a 2 mol / L zinc sulfate aqueous solution for 2 days to allow it to fully swell and absorb the electrolyte, thus obtaining a mechanical composite hydrogel electrolyte.
[0047] The morphology of the sample was observed using a JEOL 7610F scanning electron microscope from Japan, which revealed an uneven distribution of gel pore size. Figure 6 The prepared hydrogel electrolyte was used in a Zn / / Zn symmetric cell, model C2016, and tested using a Newway battery testing system at 0.5 mA cm⁻¹. -2 At a current density of 0.5 mAh cm⁻¹ -2 At its surface capacity, it can stably cycle for 1600 hours. Figure 7 ).
[0048] Example 3:
[0049] The first step is to heat and dissolve polyvinyl alcohol in deionized water and then ultrasonically mix it with clay mineral materials. The specific steps are as follows:
[0050] Take 1g of polyvinyl alcohol and 0.1g of talc and place them in 20mL of deionized water. Sonicate for 20 minutes to disperse them, and then heat and stir at 90℃ for 2 hours until the polyvinyl alcohol is completely dissolved in the deionized water.
[0051] The second step is the addition of the initiator and cross-linking agent and the preparation of the gel, the specific steps of which are as follows:
[0052] Add 3 mg of N,N'-methylenebisacrylamide and 25 mg of benzoyl peroxide to the composite solution obtained in step 1), and stir to dissolve at 40 °C for 30 min. Then add 2 g of 2-acrylamido-2-methylpropanesulfonic acid, and stir at 40 °C for 2 h. Pour the mixture into a mold and seal it, then crosslink it at 60 °C for 4 h. After freezing at -20 °C for 12 h, remove it, thaw, and demold to obtain a hydrogel.
[0053] The third step is to immerse the hydrogel in a zinc salt aqueous solution to allow it to fully swell and absorb, thus obtaining an inorganic composite hydrogel electrolyte. The specific steps are as follows:
[0054] The above hydrogel was immersed in a 2 mol / L zinc sulfate aqueous solution for 2 days to allow it to fully swell and absorb the electrolyte, thus obtaining a mechanical composite hydrogel electrolyte.
[0055] Example 4:
[0056] The first step is to heat and dissolve polyvinyl alcohol in deionized water and then ultrasonically mix it with clay mineral materials. The specific steps are as follows:
[0057] Take 1g of polyvinyl alcohol and 0.05g of zinc-based montmorillonite and place them in 20mL of deionized water. Sonicate for 20 minutes to disperse them, and then heat and stir at 90℃ for 2 hours until the polyvinyl alcohol is completely dissolved in the deionized water.
[0058] The second step is the addition of the initiator and cross-linking agent and the preparation of the gel, the specific steps of which are as follows:
[0059] Add 3 mg of dienylphenol and 30 mg of ammonium persulfate to the composite solution obtained in step 1), and stir to dissolve at 30 °C for 60 min. Then add 3 g of acrylic acid and stir at 40 °C for 2 h. Pour the mixture into a mold and seal it, then crosslink at 60 °C for 4 h. After freezing at -20 °C for 12 h, remove and thaw to obtain a hydrogel.
[0060] The third step is to immerse the hydrogel in a zinc salt aqueous solution to allow it to fully swell and absorb, thus obtaining an inorganic composite hydrogel electrolyte. The specific steps are as follows:
[0061] The above hydrogel was immersed in a 2 mol / L zinc sulfate aqueous solution for 2 days to allow it to fully swell and absorb the electrolyte, thus obtaining a mechanical composite hydrogel electrolyte.
[0062] As can be seen from the above embodiments, this invention utilizes polymer double crosslinking and clay mineral materials as inorganic fillers to prepare inorganic composite hydrogel electrolytes with excellent electrochemical performance, superior mechanical properties, and high stability. This method can effectively solve problems such as dendrite formation and corrosion of zinc metal anodes and has broad application prospects in the field of flexible wearable devices.
[0063] Matters not covered in this invention are common knowledge.
Claims
1. A method for preparing an inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries, characterized in that: Includes the following steps: (1) Add polyvinyl alcohol and clay mineral materials to deionized water and ultrasonically mix for 5-60 minutes, then heat and stir at 60-95℃ to dissolve and obtain a composite solution; The mass ratio of polyvinyl alcohol to deionized water is 1:5 to 1:30; the mass ratio of polyvinyl alcohol to clay mineral material is 100:1 to 1:
1. (2) Add an initiator and a crosslinking agent to the composite solution obtained in step 1), stir and dissolve at 20-60°C for 10-60 min to obtain a mixed solution; add polymer monomers to the mixed solution obtained above, stir thoroughly at 20-45°C, allow to stand at 50-80°C for 0.5-10 h for crosslinking, then freeze at -10--30°C for 5-15 h, and then thaw to obtain a hydrogel; Wherein, the mass ratio of the initiator to the polymer monomer is 1:50 to 1:200; the mass ratio of the crosslinking agent to the polymer monomer is 1:500 to 1:2000; and the mass ratio of the polymer monomer to polyvinyl alcohol is 1:5 to 5:
1. (3) Immerse the hydrogel in a zinc salt aqueous solution for 0.5 to 5 days to obtain an inorganic composite hydrogel electrolyte; The concentration of the zinc salt aqueous solution is 0.5–5 mol / L.
2. The method for preparing the inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries as described in claim 1, characterized in that the clay mineral material is one or more of zinc-based montmorillonite, talc, kaolinite, attapulgite, and halloysite.
3. The method for preparing the inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries as described in claim 1, characterized in that the crosslinking agent is one or more of glutaraldehyde, dienylphenol, and N,N'-methylenebisacrylamide.
4. The preparation method of the inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries as described in claim 1, characterized in that: The initiator is one or more of potassium persulfate, ammonium persulfate, and benzoyl peroxide.
5. The method for preparing the inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries as described in claim 1, characterized in that the polymer monomer is one or more of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and acrylic acid.
6. The method for preparing the inorganic composite hydrogel electrolyte for aqueous zinc-ion batteries as described in claim 1, characterized in that the zinc salt is one or more of zinc sulfate, zinc chloride, and zinc trifluoromethanesulfonate.