Preparation method of hydrogel electrolyte, hydrogel electrolyte and zinc ion battery

Abstract

The embodiment of the invention relates to the technical field of electrolytes, and provides a preparation method of a hydrogel electrolyte, the hydrogel electrolyte and a zinc ion battery, and the preparation method comprises the following steps: preparing a chitosan aqueous solution with a first preset concentration; the preparation method comprises the following steps: adding a certain amount of genipin into a chitosan aqueous solution, so that the genipin and chitosan in the chitosan aqueous solution are crosslinked at a first preset temperature; coating the cross-linked slurry on a substrate of a preset material, and drying and demolding at a second preset temperature to obtain a hydrogel electrolyte dry film; and soaking the hydrogel electrolyte dry film in a liquid electrolyte with a second preset concentration to absorb the liquid until the liquid is saturated, thereby obtaining the hydrogel electrolyte. Chitosan and genipin used in the embodiment of the invention are natural substances and are non-toxic and harmless, so that the prepared hydrogel electrolyte belongs to an environment-friendly electrolyte material, the problem that a cross-linking agent in a traditional electrolyte material is relatively high in toxicity is effectively avoided, and the problem of side reaction caused by using water as an electrolyte solvent is also avoided.

Description

Technical Field

[0001] This disclosure relates to the field of electrolyte technology, and in particular to a method for preparing a hydrogel electrolyte and a zinc-ion battery. Background Technology

[0002] Aqueous zinc-ion rechargeable batteries possess excellent safety and environmental friendliness, with inexpensive raw materials that are not limited by resources. However, traditional electrolyte materials mostly use chemical crosslinking agents, such as glutaraldehyde, which are typically highly toxic. Furthermore, aqueous zinc-ion rechargeable batteries usually use water as a solvent, leading to numerous water-induced side reactions within the battery. These include corrosion on the zinc anode surface, formation of electrochemically inert and irreversible byproducts, water decomposition, and dissolution of the positive electrode active material. These reactions result in increased battery polarization, capacity decay, and battery gas accumulation, further degrading battery performance. In addition, uneven deposition of the zinc anode in the liquid electrolyte can lead to dendrite formation, significantly impacting battery stability.

[0003] Therefore, how to reduce the toxicity of electrolyte materials, avoid water-induced side reactions in aqueous zinc-ion batteries, and prevent dendrite growth in the zinc anode has become an urgent problem to be solved in this field. Summary of the Invention

[0004] This disclosure aims to address at least one of the problems existing in the prior art by providing a method for preparing a hydrogel electrolyte, as well as the hydrogel electrolyte and zinc-ion battery.

[0005] One aspect of this disclosure provides a method for preparing a hydrogel electrolyte, the method comprising: Prepare a chitosan aqueous solution of the first preset concentration; A certain amount of genipin is added to the chitosan aqueous solution to allow the genipin to crosslink with the chitosan in the chitosan aqueous solution at a first preset temperature. The cross-linked slurry is coated onto a substrate of a preset material, dried and demolded at a second preset temperature to obtain a hydrogel electrolyte dry film. The hydrogel electrolyte dry film is immersed in a liquid electrolyte of a second preset concentration until saturation is achieved, thus obtaining the hydrogel electrolyte.

[0006] Optionally, the preparation method further includes: In the process of preparing the chitosan aqueous solution, a certain amount of acetic acid is added to the chitosan aqueous solution according to the proportion of chitosan in the chitosan aqueous solution.

[0007] Optionally, the preparation method further includes: During the cross-linking process between genipin and chitosan, zinc salt is added to the solution.

[0008] Optionally, the liquid electrolyte comprises an aqueous solution of a zinc salt, wherein the zinc salt comprises any one of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate.

[0009] Optionally, when the zinc salt is zinc sulfate, the second preset concentration ranges from 1 mol / L to 3 mol / L.

[0010] Optionally, the preset material includes polytetrafluoroethylene.

[0011] Optionally, the range of the first preset temperature is 55℃~65℃.

[0012] Optionally, the second preset temperature ranges from 65°C to 75°C.

[0013] Another aspect of this disclosure provides a hydrogel electrolyte prepared using the method described above.

[0014] Another aspect of this disclosure provides a zinc-ion battery in which the electrolyte is a hydrogel electrolyte as described above.

[0015] Compared with the prior art, the chitosan and genistein used in this disclosure are natural substances that are non-toxic and harmless. The hydrogel electrolyte prepared in this way is an environmentally friendly electrolyte material, which effectively avoids the problem of high toxicity of crosslinking agents in traditional electrolyte materials, and also avoids the side reaction problems caused by water as an electrolyte solvent. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with the corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a flowchart illustrating a method for preparing a hydrogel electrolyte according to one embodiment of the present disclosure. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the various embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and with various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this disclosure. The various embodiments can be combined with and referenced by each other without contradiction.

[0019] One embodiment of this disclosure relates to a method for preparing a hydrogel electrolyte, the process of which is as follows: Figure 1 As shown, it includes: Step S110: Prepare a chitosan aqueous solution of a first preset concentration.

[0020] Specifically, chitosan is a high molecular weight polymer and a natural alkaline polysaccharide. This embodiment does not limit the specific value of the first preset concentration. Those skilled in the art can set different first preset concentrations according to actual needs, thereby preparing chitosan aqueous solutions of different concentrations through step S110, so that the hydrogel electrolyte obtained in the final preparation contains different concentrations of chitosan to meet different application requirements.

[0021] In particular, in order to promote the dissolution of chitosan, the preparation method of hydrogel electrolyte also includes: during the preparation of chitosan aqueous solution, adding a certain amount of acetic acid to the chitosan aqueous solution according to the proportion of chitosan in the chitosan aqueous solution.

[0022] Specifically, chitosan is more soluble in acetic acid than in water. Therefore, by adding a certain amount of acetic acid to the chitosan aqueous solution, the dissolution rate of chitosan can be effectively increased, thereby shortening the dissolution time of chitosan and further shortening the preparation time of the hydrogel electrolyte.

[0023] Step S120: A certain amount of genipin is added to the chitosan aqueous solution to allow the genipin to crosslink with the chitosan in the chitosan aqueous solution at a first preset temperature.

[0024] Specifically, genipin is used as a cross-linking agent to cross-link with chitosan in the chitosan aqueous solution. The specific amount of genipin can be selected and set according to actual needs, and this embodiment does not limit this, as long as genipin can cross-link with chitosan to form a hydrogel.

[0025] To achieve better crosslinking reaction results, the crosslinking temperature, i.e., the first preset temperature, can be adjusted to increase the degree of crosslinking. For example, the range of the first preset temperature can be set to 55℃~65℃, preferably 60℃.

[0026] Specifically, to promote the cross-linking of genipin and chitosan, the preparation method of the hydrogel electrolyte further includes adding a zinc salt to the solution during the cross-linking process of genipin and chitosan. The specific amount of zinc salt can be selected and set according to actual needs, and this embodiment does not limit it.

[0027] By adding zinc salt to the solution during the crosslinking process of genipin and chitosan, the crosslinking speed of genipin and chitosan can be effectively increased, thereby greatly shortening the crosslinking reaction time and further shortening the preparation time of the hydrogel electrolyte.

[0028] In step S130, the cross-linked slurry is coated onto a substrate of a preset material and dried and demolded at a second preset temperature to obtain a hydrogel electrolyte dry film.

[0029] Specifically, after the crosslinking of genipin and chitosan is completed, the solution will turn into a blue-green slurry. Therefore, in step S130, the blue-green slurry can be coated on the substrate and dried and demolded at a second preset temperature to obtain a hydrogel electrolyte dry film.

[0030] The preset material can include polytetrafluoroethylene (PTFE). Because PTFE has excellent demolding properties, high temperature resistance, and corrosion resistance, setting the base material to PTFE can effectively reduce demolding difficulty and make demolding easier.

[0031] To improve efficiency during drying and demolding, the drying and demolding temperature, i.e., the second preset temperature, can be adjusted. For example, the range of the second preset temperature is 65℃~75℃, preferably 70℃.

[0032] Step S140: Immerse the hydrogel electrolyte dry film in a liquid electrolyte of a second preset concentration until saturation is achieved, thereby obtaining the hydrogel electrolyte.

[0033] Specifically, the liquid electrolyte includes an aqueous solution of zinc salt, wherein the zinc salt includes any one of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate, with zinc sulfate being preferred.

[0034] The second preset concentration can be selected and set according to actual needs. For example, when the zinc salt is zinc sulfate, the range of the second preset concentration can be 1 mol / L to 3 mol / L, preferably 2 mol / L.

[0035] To enable those skilled in the art to better understand the above embodiments, a specific example is provided below for illustration.

[0036] A method for preparing a hydrogel electrolyte includes the following steps: (1) Prepare chitosan aqueous solutions of different concentrations. During the preparation process, add a certain amount of acetic acid according to the proportion of chitosan in the chitosan aqueous solution to promote the dissolution of chitosan.

[0037] (2) Add a certain amount of genipin to the chitosan solution and allow the genipin to crosslink with the chitosan in the chitosan solution at a temperature of 60°C. During the crosslinking process, add a small amount of zinc salt to the solution to promote the crosslinking reaction between genipin and chitosan. By adding zinc salt to the solution during the crosslinking process, the crosslinking time can be significantly reduced. For example, the crosslinking time can be shortened from 6 hours to 1 hour.

[0038] (3) The blue-green slurry was coated on a polytetrafluoroethylene substrate and dried at 70°C to obtain a hydrogel electrolyte dry film.

[0039] (4) Immerse the hydrogel electrolyte dry film in a zinc sulfate electrolyte solution with a concentration of 2 mol / L until saturation to obtain the hydrogel electrolyte.

[0040] The method for preparing hydrogel electrolytes provided in this disclosure, compared with the prior art, uses chitosan and genistein, which are natural substances that are non-toxic and harmless. The hydrogel electrolytes prepared in this way are environmentally friendly electrolyte materials, effectively avoiding the problem of high toxicity of crosslinking agents in traditional electrolyte materials, and also avoiding the side reaction problems caused by water as an electrolyte solvent.

[0041] Another embodiment of this disclosure relates to a hydrogel electrolyte, which is prepared using the preparation method of the hydrogel electrolyte described in the above embodiments.

[0042] Another embodiment of this disclosure relates to a zinc-ion battery in which the electrolyte is a hydrogel electrolyte as described in the above embodiments.

[0043] Specifically, in addition to the hydrogel electrolyte described in the above embodiments, the zinc-ion battery also includes a positive electrode, a negative electrode, and a battery casing. The positive electrode active material can include various aqueous battery positive electrode materials, such as manganese-based materials, vanadium-based materials, and Prussian blue analogues. The negative electrode can be a negative electrode material containing metallic zinc, zinc alloys, zinc powder, etc.

[0044] By using the hydrogel electrolyte prepared by the method described in the above embodiments, the problem of high toxicity of crosslinking agents in traditional electrolyte materials can be effectively avoided. It also avoids side reaction problems caused by water as an electrolyte solvent and dendrite growth of metallic zinc anode.

[0045] Those skilled in the art will understand that the above embodiments are specific implementations of this disclosure, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this disclosure.

Claims

1. A method for preparing a hydrogel electrolyte, characterized in that, The preparation method includes: Prepare a chitosan aqueous solution of the first preset concentration; A certain amount of genipin is added to the chitosan aqueous solution to allow the genipin to crosslink with the chitosan in the chitosan aqueous solution at a first preset temperature. The cross-linked slurry is coated onto a substrate of a preset material, dried and demolded at a second preset temperature to obtain a hydrogel electrolyte dry film. The hydrogel electrolyte dry film is immersed in a liquid electrolyte of a second preset concentration until saturation is achieved, thus obtaining the hydrogel electrolyte.

2. The preparation method according to claim 1, characterized in that, The preparation method further includes: In the process of preparing the chitosan aqueous solution, a certain amount of acetic acid is added to the chitosan aqueous solution according to the proportion of chitosan in the chitosan aqueous solution.

3. The preparation method according to claim 1, characterized in that, The preparation method further includes: During the cross-linking process between genipin and chitosan, zinc salt is added to the solution.

4. The preparation method according to claim 1, characterized in that, The liquid electrolyte comprises an aqueous solution of a zinc salt, wherein the zinc salt comprises any one of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate.

5. The preparation method according to claim 4, characterized in that, When the zinc salt is zinc sulfate, the second preset concentration ranges from 1 mol / L to 3 mol / L.

6. The preparation method according to claim 1, characterized in that, The preset material includes polytetrafluoroethylene.

7. The preparation method according to claim 1, characterized in that, The first preset temperature range is 55℃~65℃.

8. The preparation method according to claim 1, characterized in that, The second preset temperature range is 65℃~75℃.

9. A hydrogel electrolyte, characterized in that, The hydrogel electrolyte is prepared using the method described in any one of claims 1 to 8.

10. A zinc-ion battery, characterized in that, The electrolyte in the zinc-ion battery is the hydrogel electrolyte described in claim 9.

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