CN-121983683-A - Hydroxy phosphate composite hydrogel electrolyte and preparation method and application thereof

Abstract

The invention provides a preparation method of a hydroxyl phosphate composite hydrogel electrolyte, which comprises the steps of sequentially soaking hydrogel in a metal salt precursor solution, a phosphate radical solution and a zinc salt solution, and forming hydroxyl phosphate in a hydrogel network by metal ions in the metal salt precursor and a mineralizer through in-situ mineralization reaction to obtain the hydroxyl phosphate composite hydrogel electrolyte. The invention also provides the hydroxy phosphate composite hydrogel electrolyte obtained by the preparation method and application thereof in zinc ion batteries. The invention can obviously improve the circulation stability of the electrolyte by introducing the hydroxy phosphate into the hydrogel electrolyte and applying the obtained electrolyte to the cathode of the zinc ion battery.

Inventors

• WANG HONGFEI
• ZHAO MING
• WANG MENG

Assignees

• 浙江师范大学

Dates

Publication Date

20260505

Application Date

20260327

Claims (10)

1. 1. A preparation method of a hydroxyl phosphate composite hydrogel electrolyte is characterized by comprising the steps of sequentially soaking hydrogel in a metal salt precursor solution, a phosphate radical solution and a zinc salt solution, and forming hydroxyl phosphate in a hydrogel network through in-situ mineralization reaction of metal ions in the metal salt precursor and the phosphate radical solution to obtain the hydroxyl phosphate composite hydrogel electrolyte.
2. 2. The method for preparing the hydroxy phosphate composite hydrogel electrolyte according to claim 1, wherein the hydrogel is selected from the group consisting of polyacrylamide hydrogel, collagen, gelatin and polyvinyl alcohol.
3. 3. The preparation method of the hydroxyl phosphate composite hydrogel electrolyte according to claim 2, wherein the preparation method of the polyacrylamide hydrogel is characterized in that an acrylamide monomer, an N, N' -methylene bisacrylamide crosslinking agent and an initiator are dissolved in deionized water to react to obtain the polyacrylamide hydrogel.
4. 4. The method for preparing a hydroxy phosphate composite hydrogel electrolyte according to claim 1, wherein the metal salt precursor is selected from one or more of calcium chloride, ferric chloride or magnesium chloride, and the phosphate solution is selected from one or more of sodium dihydrogen phosphate or phosphoric acid.
5. 5. The method for preparing a hydroxy phosphate composite hydrogel electrolyte according to claim 1, wherein the zinc salt is selected from zinc triflate, zinc sulfate or zinc chloride.
6. 6. The method for preparing a hydroxy phosphate composite hydrogel electrolyte according to claim 1, wherein the molar ratio of metal ions to phosphate in the metal salt is 1.6 or more.
7. 7. The method for preparing a hydroxy phosphate composite hydrogel electrolyte according to claim 6, wherein the concentration of the metal salt precursor solution in the mixed solution is 0.004-0.4 mol/L and the concentration of the phosphate solution is 0.0025-0.25 mol/L.
8. 8. A hydroxy phosphate composite hydrogel electrolyte obtained by the method of any one of claims 1 to 7.
9. 9. Use of the hydroxy phosphate composite hydrogel electrolyte of claim 8 in a zinc ion battery.
10. 10. The use according to claim 9, wherein the zinc ion battery is a symmetrical zinc battery, an asymmetrical copper zinc battery or a full battery.

Description

Hydroxy phosphate composite hydrogel electrolyte and preparation method and application thereof Technical Field The invention belongs to the technical field of aqueous zinc ion battery electrolyte, and particularly relates to a hydroxy phosphate composite hydrogel electrolyte, a preparation method and application thereof. Background The water-based zinc ion battery has become an important research object of a new generation of energy storage system because of low cost and excellent safety performance. However, a key challenge faced by the development of aqueous zinc ion batteries is the formation of zinc dendrites on the surface of the zinc metal anode during cycling. Uneven deposition of Zn 2+ can lead to dendrite growth, possibly penetrating the separator to cause short circuits, severely affecting battery performance and safety performance. Solving this problem is important to extend the cycle life of the battery and to realize its commercial application. In order to promote stable operation of the zinc anode, the main solutions at present are to introduce additives into the electrolyte, modify the surface structure of the electrode, design hydrogel electrolyte and the like. Hydrogel electrolytes have superior properties to conventional liquid electrolytes due to their limited water content and superior mechanical properties. For example, an amphoteric cellulose-based double network hydrogel electrolyte as disclosed in journal ANGEWANDTE CHEMIE International Edition (2023, 62, 202217833) directs Zn 2+ deposition to inhibit dendrite growth, thereby producing an ultra-stable Zn negative electrode, and a multi-component crosslinked hydrogel electrolyte as disclosed in journal Advanced Functional Materials (2022, 32, 2112540) to inhibit zinc dendrites to achieve a stable aqueous zinc ion battery. Therefore, how to design a simple hydrogel electrolyte to effectively realize the battery performance and the safety performance of the zinc ion battery is a technical problem to be solved in the current field. Disclosure of Invention The invention aims to provide a preparation method of a hydroxyl phosphate composite hydrogel electrolyte, which can obviously improve the cycling stability of the electrolyte by introducing hydroxyl phosphate into the hydrogel electrolyte and applying the obtained electrolyte to a zinc ion battery cathode. A preparation method of a hydroxyl phosphate composite hydrogel electrolyte comprises the steps of sequentially soaking hydrogel in a metal salt precursor solution, a phosphate radical solution and a zinc salt solution, and forming hydroxyl phosphate in a hydrogel network by metal ions and phosphate radicals in the metal salt precursor through in-situ mineralization reaction to obtain the hydroxyl phosphate composite hydrogel electrolyte. The invention has the technical concept that the inorganic component hydroxy phosphate is uniformly introduced into the hydrogel network structure through a biomimetic mineralization strategy, the hydroxy phosphate forms a hydrogen bond with water molecules through surface hydroxy groups to reduce the activity of free water, on the other hand, hydroxy phosphate molecules can be preferentially adsorbed and constructed on the surface of a zinc negative electrode to form a protective layer so as to inhibit dendrite growth, and meanwhile, the unique three-dimensional network structure can guide zinc ions to be orderly deposited so as to realize multiple protection of the zinc negative electrode. The hydrogel is selected from polyacrylamide hydrogel, collagen, gelatin or polyvinyl alcohol. The preparation method of the polyacrylamide hydrogel comprises the steps of dissolving an acrylamide monomer, an N, N' -methylene bisacrylamide crosslinking agent and an initiator (such as ammonium persulfate) in deionized water, and reacting to obtain the polyacrylamide hydrogel. The metal salt precursor is selected from one or more of calcium chloride, ferric chloride or magnesium chloride, and the phosphate radical solution is selected from one or more of sodium dihydrogen phosphate or phosphoric acid. The zinc salt is selected from zinc triflate, zinc sulfate or zinc chloride. The molar ratio of metal ions to phosphate radicals in the metal salt is greater than or equal to 1.6, and the hydroxyl phosphate can be generated under the ratio. Further, the concentration of the metal salt precursor solution in the mixed solution is 0.004-0.4 mol/L, and the concentration of the phosphate radical solution is 0.0025-0.25 mol/L. The invention also provides the hydroxy phosphate composite hydrogel electrolyte obtained by the preparation method. The invention also provides application of the hydroxyl phosphate composite hydrogel electrolyte in a zinc ion battery. The zinc ion battery is a symmetrical zinc battery, an asymmetrical copper zinc battery or a full battery. Compared with the conventional hydrogel electrolyte, the invention has the following improvement effects: the