Preparation method of organic eutectic gel electrolyte and zinc metal battery

Abstract

The invention provides a preparation method of an organic eutectic gel electrolyte and a zinc metal battery, and belongs to the technical field of gel electrolytes. According to the preparation method, a novel gel electrolyte is formed by in-situ compounding of organic eutectic and gel through ultraviolet light. The organic eutectic gel electrolyte provided by the invention can form a crystal structure which is more stable in different environments through non-covalent bond interaction of hydrogen bonds, Van der Waals force and the like among the components, so that the problems of instability and poorer solubility of small organic molecules in the electrolyte are effectively avoided; the eutectic can combine organic small molecule components with different functions to realize functional complementation and synergistic enhancement, so that balance optimization of stability and specific capacity can be realized, and the problem that dendritic crystal growth, corrosion and hydrogen evolution of a zinc negative electrode are difficult to solve at the same time in the existing gel electrolyte is solved; and the regulation and control capability on a solvation structure at a zinc interface and an electrode / electrolyte interface is limited.

Description

Technical Field

[0001] This invention belongs to the field of gel electrolyte technology, specifically relating to a method for preparing an organic eutectic gel electrolyte and a zinc metal battery. Background Technology

[0002] Aqueous zinc metal batteries, as a strong contender for next-generation energy storage technology, have attracted widespread attention due to their high safety, low cost, and environmental friendliness. The electrolyte, as the core component of the battery, directly determines its overall performance. Traditional liquid electrolytes have high ionic conductivity, but their inherent problems are also significant: water has a narrow electrochemical window, limiting the battery's operating voltage; side reactions between water molecules and the zinc anode, such as hydrogen evolution and corrosion, lead to poor battery cycle stability, and there is also a risk of leakage.

[0003] To overcome these shortcomings, researchers have developed gel polymer electrolytes, which immobilize water and zinc salts through a polymer network to form a quasi-solid-state electrolyte with good mechanical properties and ion conductivity. These electrolytes not only suppress zinc dendrite growth but also improve battery flexibility and safety. However, existing gel electrolyte technologies still face many challenges. To improve performance, researchers typically add inorganic fillers, such as silica or zinc oxide, to enhance mechanical strength; or add small organic molecules, such as ethylene glycol or glycerol, to reduce water activity and suppress side reactions. However, these methods often only solve a single problem and may even introduce new drawbacks. For example, inorganic particles tend to agglomerate, affecting the uniformity of ion transport; and small organic molecules may precipitate during cycling, leading to performance degradation. More fundamentally, existing strategies lack synergistic effects and cannot simultaneously address the multiple problems faced by zinc anodes, such as dendrite growth, corrosion, and hydrogen evolution. On the other hand, existing additives have limited ability to regulate the solvation structure at the zinc interface and the electrode / electrolyte interface, making it difficult to fundamentally improve the uniformity of zinc deposition and interfacial stability.

[0004] Therefore, developing a novel electrolyte system that can synergistically solve the above problems has become the key to promoting the commercial application of aqueous zinc-ion batteries. Summary of the Invention

[0005] In view of the problems existing in the background technology, the purpose of this invention is to provide a method for preparing an organic eutectic gel electrolyte and a zinc metal battery. This preparation method utilizes an organic eutectic and a gel to form a novel gel electrolyte through in-situ composite under ultraviolet light. This solves the problems of existing gel electrolytes in that they cannot simultaneously address the dendrite growth, corrosion, and hydrogen evolution faced by the zinc anode, as well as the limited ability to control the solvation structure at the zinc interface and the electrode / electrolyte interface.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for preparing an organic eutectic gel electrolyte includes the following steps:

[0008] S1. Dissolve the electron acceptor (A) and electron donor (D) in an organic solvent to obtain a mixed solution. Then, heat the mixed solution with ultrasound, allow it to stand and evaporate naturally, and wash it to obtain an organic eutectic.

[0009] S2. Mix the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution;

[0010] S3. The gel prepolymer obtained in S2 is subjected to ultraviolet irradiation to react and obtain organic eutectic gel electrolyte.

[0011] Further, the electron acceptor is one or more of 1,2,4,5-tetracyanobenzene (TCNB), 7,7,8,8-tetracyanobenzene dimethylform (TCNQ), and 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b:4,5-b']-dithiophene (DTTCNQ).

[0012] Furthermore, the electron donor is one or more of naphthobenzofuran (BNF), 1,4,8,11-tetramethyl-6,13-triethylsilylethynylpentabenzene (TM), and indo[2,3-B]carbazole (5,7-ICN).

[0013] Furthermore, in S1, the organic solvent is one or more of dichloroethane or tetrahydrofuran; the cleaning agent is petroleum ether.

[0014] Further, in S1, the molar ratio of electron acceptor to electron donor is 2:(1-4); the total concentration of electron acceptor and electron donor in the mixed solution is 1-5 mg / mL.

[0015] Furthermore, in S2, the mass ratio of polymer, photoinitiator and organic eutectic is (5-20):1:(1-3).

[0016] Further, the polymer is one or more of acrylamide, N,N'-methylenebisacrylamide, polyvinyl alcohol, polyethylene glycol, or sodium carboxymethyl cellulose.

[0017] Further, the photoinitiator is one or more of 2,4,6-(trimethylbenzoyl)-diphenylphosphine oxide, 1-hydroxycyclohexylphenyl ketone, or 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0018] Further, the zinc salt solution is one or more of ZnSO4, Zn(OTF)2, ZnCl2 or ZnNO3; the concentration of the zinc salt solution is 0.5-3 mol / L.

[0019] Furthermore, in S3, the ultraviolet wavelength is 254-365nm.

[0020] A zinc metal battery includes a positive electrode, an organic eutectic gel electrolyte, and a negative electrode;

[0021] The negative electrode is a zinc electrode, and the positive electrode is VO2, V2O5, NaVO3, or V. 13 One or more of O6.

[0022] Furthermore, the zinc electrode has a thickness of 30-100 μm, and the organic eutectic gel electrolyte has a thickness of 0.8-1.2 mm.

[0023] The mechanism of this invention is as follows:

[0024] This invention provides an organic eutectic gel electrolyte, a novel quasi-solid-state electrolyte system formed by in-situ ultraviolet light composite bonding of organic eutectic crystals with a gel polymer network. Unlike traditional deep eutectic solvents or simple gel systems, this system utilizes organic eutectic crystals as functional crystalline units, existing in a stable and uniformly dispersed form within the gel network. The eutectic crystal is self-assembled from two or more components in a specific stoichiometric ratio. The components interact non-covalently through hydrogen bonds, halogen bonds, π–π stacking, and charge transfer, constructing a highly ordered supramolecular crystal structure. During the ultraviolet light-induced composite process, these eutectic molecules and gel polymer segments form a tight bond through non-covalent forces, allowing the eutectic microcrystalline regions to interpenetrate and stabilize with the flexible gel network. This constructs an electrolyte framework that possesses both rigid support and flexible regulation, embedding or cross-linking within the three-dimensional network of the gel. Thanks to this molecular-level interaction, the organic eutectic crystals do not precipitate or aggregate within the gel, but instead form structurally stable and uniformly distributed crystalline microregions, achieving a synergistic unity of crystalline order and a flexible gel network.

[0025] In this composite system, the solid-state stacking structure of the organic eutectic and the polymeric network of the gel complement each other, jointly constructing continuous ion conduction channels and a stable interfacial environment. On the one hand, the ordered lattice of the eutectic and its internal polar functional groups (such as cyano, ethynyl, and thiophene rings) can effectively regulate the electronic structure of the system and the solvation environment of zinc ions. The electron attraction of the cyano group can improve the conductivity and ion transport capacity of the material; the conjugated electronic structure of the thiophene ring helps to promote the reversible deposition and stripping of zinc ions; the high electron density of the ethynyl group enhances the electron transfer rate; and the presence of the benzene ring skeleton further improves the structural stability of the system and reduces the volume change during charging and discharging. The synergistic effect of these molecular functional groups makes the deposition of zinc ions more uniform, fundamentally inhibiting the formation and growth of dendrites.

[0026] On the other hand, the gel network provides a stable dispersion carrier for the organic cocrystal. Its flexible three-dimensional structure not only ensures the mechanical integrity of the electrolyte but also suppresses the free movement of active water molecules through a confinement effect, thereby reducing the probability of water reduction side reactions. The interaction between the cocrystal molecules and the gel segments can also regulate the solvation structure of the system, reduce the active water content, and increase the Gibbs free energy of the system, thus suppressing the kinetics of water splitting and significantly reducing hydrogen evolution. Compared with traditional liquid electrolytes or physically mixed small molecule addition systems, this in-situ composite organic cocrystal gel structure has higher stability and longer cycle life, and will not exhibit small molecule precipitation or performance degradation due to high pressure or long-term operation.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] The organic cocrystal gel electrolyte containing electron donors and acceptors provided by this invention achieves multiple adjustments and optimizations to its electrochemical performance through the synergistic effect of the cocrystal system and the gel network. The supramolecular crystal structure of the organic cocrystal in this electrolyte not only endows the cocrystal with stable crystallization characteristics and an intermolecular interaction network, but also allows it to exist in a uniformly dispersed and firmly bound form within the gel polymer.

[0029] In this system, electron donors and electron acceptors each perform different but complementary functions. Electron donor molecules possess excellent electron transport capabilities and chemical stability, enabling them to preferentially adsorb onto the zinc electrode surface, forming a dense and uniform interfacial protective layer. This protective layer effectively suppresses localized electric field concentration and disordered dendrite growth, thereby improving the deposition uniformity and cycle stability of the zinc anode. Simultaneously, electron acceptor molecules, with their strong electrochemical activity and coordination ability, can bind with Zn... 2+The formation of stable coordination structures alters the original solvation environment, optimizes ion migration pathways, thereby improving transport kinetics and reducing polarization. The charge transfer interaction between the donor and acceptor not only enhances the electronic coupling effect of the system but also provides a more continuous transport channel for the electrolyte's conductivity and interfacial electrochemical reactions.

[0030] Compared to traditional electrolyte systems with single small molecule additions, the electron donor-electron acceptor organic cocrystal gel electrolyte constructed in this invention maintains high stability of its crystal structure under different electrochemical environments due to multiple non-covalent interactions between components, avoiding common problems such as dissolution, precipitation, and decomposition in small molecule systems. The synergistic combination of different functional components in the cocrystal enables the system to possess dual channels for electron and ion transport, achieving functional complementarity and performance synergy. Simultaneously, the gel matrix provides a three-dimensional confined space and flexible network support, not only preventing the aggregation of cocrystal microcrystals but also reducing the participation of active water through the confinement effect, further inhibiting the hydrogen evolution reaction.

[0031] This synergistic mechanism of eutectic gel significantly broadens the electrochemical stability window of the electrolyte, effectively suppresses water splitting side reactions, and results in assembled batteries exhibiting higher initial specific capacity and capacity retention. Dendrite formation during cycling is effectively suppressed, interfacial reactions are more controllable, and the dissolution problem of vanadium-based cathodes is also significantly alleviated. Therefore, the organic eutectic gel electrolyte of this invention provides a novel material solution for the safety and reliability of aqueous zinc batteries while achieving high energy density and long cycle life. Attached Figure Description

[0032] Figure 1 This is a diagram of the crystal packing structure of an organic eutectic.

[0033] Figure 2 The image shows the XRD pattern of the organic eutectic.

[0034] Figure 3 The image shows the FT-IR spectrum of the organic eutectic.

[0035] Figure 4 Optical photographs of different gel electrolytes.

[0036] Figure 5 Images of different gel electrolytes under ultraviolet irradiation.

[0037] Figure 6 Charge-discharge test diagrams of symmetrical batteries composed of different gel electrolytes.

[0038] Figure 7 Cyclic performance curves of full cells composed of different gel electrolytes

[0039] Figure 8Capacity retention performance of full cells with different gel electrolyte compositions. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0041] Example 1

[0042] A method for preparing an organic eutectic gel electrolyte, comprising:

[0043] S1. Dissolve the electron acceptor and electron donor in an organic solvent to obtain a mixed solution. After ultrasonic heating and natural evaporation, the mixed solution is washed with petroleum ether to obtain an organic eutectic.

[0044] The electron acceptor is 1,2,4,5-tetracyanobenzene; the electron donor is naphthobenzofuran; and the organic solvent is dichloroethane.

[0045] The molar ratio of electron acceptor to electron donor is 2:1; the concentration of the mixed solution is 1 mg / mL;

[0046] S2. After mixing the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution;

[0047] The mass ratio of the polymer, photoinitiator, and organic eutectic is 5:1:1;

[0048] The polymer is polyvinyl alcohol; the photoinitiator is 2,4,6-(trimethylbenzoyl)-diphenylphosphine oxide; the zinc salt solution is a ZnSO4 solution with a concentration of 0.5 mol / L.

[0049] S3. Place the gel prepolymer solution on the surface of the zinc electrode and react in situ on the surface of the zinc electrode under ultraviolet irradiation to obtain an organic eutectic gel electrolyte; the ultraviolet wavelength is 254 nm; the thickness of the zinc electrode is 30 μm.

[0050] Example 2

[0051] A method for preparing an organic eutectic gel electrolyte, comprising:

[0052] S1. Dissolve the electron acceptor and electron donor in an organic solvent to obtain a mixed solution. After ultrasonic heating and natural evaporation, the mixed solution is washed with petroleum ether to obtain an organic eutectic.

[0053] The electron acceptor is 7,7,8,8-tetracyanobenzoquinone dimethyl ether; the electron donor is 1,4,8,11-tetramethyl-6,13-triethylsilylacetylenepentene; and the organic solvent is tetrahydrofuran.

[0054] The molar ratio of electron acceptor to electron donor is 2:4; the concentration of the mixed solution is 5 mg / mL;

[0055] S2. After mixing the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution;

[0056] The mass ratio of the polymer, photoinitiator, and organic eutectic is 20:1:3;

[0057] The polymer is polyethylene glycol; the photoinitiator is 1-hydroxycyclohexylphenyl ketone; the zinc salt solution is Zn(OTF)2 solution; the concentration of the zinc salt solution is 3 mol / L.

[0058] S3. The gel prepolymer solution reacts on the surface of the zinc electrode under ultraviolet irradiation to obtain an organic eutectic gel electrolyte; the ultraviolet wavelength is 365nm; the thickness of the zinc electrode is 100μm.

[0059] Example 3

[0060] A method for preparing an organic eutectic gel electrolyte, comprising:

[0061] S1. Dissolve the electron acceptor and electron donor in an organic solvent to obtain a mixed solution. After ultrasonic heating and natural evaporation, the mixed solution is washed with petroleum ether to obtain an organic eutectic.

[0062] The electron acceptor is 7,7,8,8-tetracyanobenzoquinone dimethane and 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b:4,5-b']-dithiophene in a mass ratio of 1:1; the electron donor is 1,4,8,11-tetramethyl-6,13-triethylsilylacetylene and indo[2,3-B]carbazole in a mass ratio of 1:1; the organic solvent is dichloroethane and tetrahydrofuran in a volume ratio of 1:1.

[0063] The molar ratio of electron acceptor to electron donor is 2:3; the concentration of the mixed solution is 3 mg / mL.

[0064] S2. After mixing the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution;

[0065] The mass ratio of the polymer, photoinitiator, and organic eutectic is 10:1:2;

[0066] The polymer is sodium carboxymethyl cellulose; the photoinitiator is 2,4,6-(trimethylbenzoyl)-diphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone in a mass ratio of 1:1; the zinc salt solution is a ZnCl2 and ZnNO3 solution in a mass ratio of 1:1; the concentration of the zinc salt solution is 2 mol / L.

[0067] S3. The gel prepolymer solution reacts on the surface of the zinc electrode under ultraviolet irradiation to obtain an organic eutectic gel electrolyte; the ultraviolet wavelength is 302 nm; the thickness of the zinc electrode is 80 μm.

[0068] Example 4

[0069] A method for preparing an organic eutectic gel electrolyte, comprising:

[0070] S1. Dissolve the electron acceptor and electron donor in an organic solvent to obtain a mixed solution. After ultrasonic heating and natural evaporation, the mixed solution is washed with petroleum ether to obtain an organic eutectic.

[0071] The electron acceptor is 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b:4,5-b']-dithiophene; the electron donor is 1,4,8,11-tetramethyl-6,13-triethylsilylacetylenepentene; and the organic solvent is dichloroethane and tetrahydrofuran in a volume ratio of 1:1.

[0072] The molar ratio of electron acceptor to electron donor is 1:1; the concentration of the mixed solution is 1 mg / mL;

[0073] S2. After mixing the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution;

[0074] The mass ratio of the polymer, photoinitiator and organic eutectic is (5-20):1:(1-3);

[0075] The polymer is acrylamide and N,N'-methylenebisacrylamide in a mass ratio of 50:1; the photoinitiator is 2,4,6-(trimethylbenzoyl)-diphenylphosphine oxide; the zinc salt solution includes Zn(OTF)2 solution; the concentration of the zinc salt solution is 3 mol / L.

[0076] S3. The gel prepolymer solution reacts on the surface of the zinc electrode under ultraviolet irradiation to obtain an organic eutectic gel electrolyte; the ultraviolet wavelength is 365 nm; the thickness of the zinc electrode is 80 μm.

[0077] Comparative Example 1

[0078] The gel electrolyte was prepared according to the steps of Example 4, except that S1 was omitted and the organic eutectic in S2 was removed, while the other steps remained unchanged.

[0079] Comparative Example 2

[0080] The gel electrolyte was prepared according to the steps of Example 4, except that no electron donor was added in S1, while the other steps remained unchanged.

[0081] Comparative Example 3

[0082] The gel electrolyte was prepared according to the steps of Example 4, except that no electron acceptor was added in S1, while the other steps remained unchanged.

[0083] Comparative Example 4

[0084] The gel electrolyte was prepared according to the steps of Example 4, except that S1 was omitted, and the organic eutectic in S2 was replaced with an electron donor and an electron acceptor, while the other steps remained unchanged.

[0085] The crystal stacking structure of the organic eutectic prepared in Example 4 is as follows: Figure 1 As shown, the donor and acceptor molecules are co-crystalized in a 1:1 molar ratio and arranged in a mixed-packing manner. The organic co-crystal preferentially grows along the a-axis, and the distance between DA molecules is 3.52 Å, indicating strong π-π interactions. Along the packing direction of the donor and acceptor molecules, there are S…C short-contact interactions between the donor and acceptor molecules at a distance of 3.496 Å. In addition, there are CH…N hydrogen bonds at a distance of 2.697 Å. The acceptor molecule is fixed by the four donor molecules through the aforementioned weak interactions, effectively stabilizing the supramolecular framework and eliminating disorder in the acceptor molecule.

[0086] The grown organic eutectic was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), and the characterization results are as follows: Figure 2 and Figure 3 As shown. Figure 2 The XRD patterns showed that the diffraction peaks of the organic eutectic powder differed significantly from those of the D / A single component, indicating that the donor and acceptor molecules formed a highly ordered organic eutectic structure through solution self-assembly. FT-IR results showed that the C≡N stretching vibration peaks of the acceptor molecule and the eutectic were located at 2214 cm⁻¹, respectively. 1 and 2212 cm⁻ 1 The slight shift in the characteristic peak demonstrates the existence of charge transfer interactions between DA molecules.

[0087] Optical photographs of the blank gel of Comparative Example 1, the gel doped with only D of Comparative Example 2, the gel doped with only A of Comparative Example 3, the physically added gel of Comparative Example 4, and the organic eutectic gel of Example 4 are shown below. Figure 4As shown in the figure. The results show that Comparative Example 3, with only A added, did not polymerize, while Comparative Example 4, although its viscosity increased, still did not polymerize; Comparative Examples 1, 2, and 4 successfully polymerized, forming quasi-solid gel electrolytes. This is because A may consume free radicals from the photoinitiator, thus causing the polymer crosslinking to fail; at the same time, physically added D+A exhibits partial molecular recognition in solution, resulting in increased viscosity. The successful synthesis of the organic eutectic gel indicates that it forms a stable crystal structure through non-covalent bond forces, preventing A from consuming free radicals. This marks a fundamental difference between organic eutectic gels and those with physically added D+A.

[0088] Figure 5 Images of different gel electrolytes under UV irradiation. The physically added gel in Comparative Example 4 exhibits fluorescence under UV light, while the organic eutectic in Example 4 does not, further proving the aforementioned point.

[0089] Since the gels of Comparative Example 3 (with only A added) and Comparative Example 4 (with physical addition of D+A) did not polymerize, the positive and negative electrodes of the battery would come into direct contact and short-circuit. Therefore, these two electrolytes cannot be used to assemble batteries.

[0090] Therefore, the blank gel of Comparative Example 1, the gel of Comparative Example 2 with only added D, and the organic eutectic gel of Example 4 were used to assemble button cells, and charge-discharge tests were performed on a Blue Battery testing system. The button cell assembly process was as follows: the negative electrode shell, spring, gasket, zinc negative electrode, gel electrolyte, vanadium positive electrode, and positive electrode shell were sequentially packaged to obtain a zinc metal battery; VO2 was used as the vanadium positive electrode. The results of the symmetrical cells are as follows... Figure 6 As shown, at 0.5 mA•cm -2 and 0.5mAh•cm -2 Under the specified conditions, the blank gel, the gel with only added D, and the organic eutectic gel were run for 155, 862, and 1562 hours, respectively. The gel with only added D showed a significant growth compared to the blank gel, but it was still insufficient compared to the organic eutectic gel of Example 4. This indicates that the organic eutectic gel electrolyte can be synergistically optimized by D and A, inducing uniform electroplating / stripping of zinc ions at the interface and forming a uniform protective layer, thereby better suppressing the growth of zinc dendrites and ensuring the cycle stability of the battery during long-term operation.

[0091] Full cell results as follows Figure 7 and Figure 8 As shown, the initial capacity of the gel with added organic eutectic (186.6 mAh•g) -1 The capacity retention after 5000 cycles (57.2%) was significantly higher than that of the gel with only added D (184.7 mAh•g). -1 (and 40.4%) and blank gel (165 mAh•g)-1 Compared to 28.4%, this represents a significant improvement. Based on the full-cell cycling performance, it is inferred that the organic eutectic gel alters the Zn... 2+ The solvation environment improves transport kinetics and better suppresses the dissolution of vanadium cathode, avoiding excessive capacity reduction and loss.

[0092] The combined growth of D and A in organic eutectics, compared to single organic small molecules, allows for better functional complementarity and synergistic enhancement, thereby achieving a balanced optimization of cycle stability and specific capacity in symmetric and full-cell batteries. The combination of organic eutectics and gel electrolytes effectively addresses current limitations such as leakage in liquid electrolytes, dendrite growth, severe hydrogen evolution, easy polymerization of inorganic additives, instability of single organic small molecules, uneven zinc interfacial plating / stripping, easy dissolution of vanadium cathodes, and poor cycle stability of ordinary gels, bringing further possibilities for achieving long-cycle and high-performance zinc metal batteries.

[0093] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A method for preparing an organic eutectic gel electrolyte, characterized in that, Includes the following steps: S1. Dissolve the electron acceptor and electron donor in an organic solvent to obtain a mixed solution. Then, heat the mixed solution with ultrasound, allow it to stand and evaporate naturally, and wash it to obtain an organic eutectic. S2. Mix the polymer, photoinitiator and organic eutectic, add zinc salt solution to obtain gel prepolymer solution; S3. The gel prepolymer obtained in S2 is subjected to ultraviolet irradiation to react and obtain organic eutectic gel electrolyte.

2. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, The electron acceptor is one or more of 1,2,4,5-tetracyanobenzene, 7,7,8,8-tetracyanobenzene dimethyl benzo[1,2-b:4,5-b']-dithiophene; the electron donor is one or more of naphthobenzofuran, 1,4,8,11-tetramethyl-6,13-triethylsilylacetylenepentene, and indo[2,3-B]carbazole.

3. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, In S1, the molar ratio of electron acceptor to electron donor is 2:(1-4); the total concentration of electron acceptor and electron donor in the mixed solution is 1-5 mg / mL.

4. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, In S1, the organic solvent is one or more of dichloroethane or tetrahydrofuran; the cleaning agent is petroleum ether.

5. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, In S2, the mass ratio of polymer, photoinitiator and organic eutectic is (5-20):1:(1-3).

6. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, The polymer is one or more of acrylamide, N,N'-methylenebisacrylamide, polyvinyl alcohol, polyethylene glycol, or sodium carboxymethyl cellulose; the photoinitiator is one or more of 2,4,6-(trimethylbenzoyl)-diphenylphosphine oxide, 1-hydroxycyclohexylphenyl ketone, or 2-hydroxy-2-methyl-1-phenyl-1-propanone.

7. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, The zinc salt solution is one or more of ZnSO4, Zn(OTF)2, ZnCl2 or ZnNO3; the concentration of the zinc salt solution is 0.5-3 mol / L.

8. The method for preparing the organic eutectic gel electrolyte as described in claim 1, characterized in that, In S3, the wavelength of ultraviolet light during ultraviolet irradiation is 254-365nm.

9. A zinc metal battery, characterized in that, Includes a positive electrode, an organic eutectic gel electrolyte prepared according to any one of claims 1-8, and a negative electrode; The negative electrode is a zinc electrode, and the positive electrode is VO2, V2O5, NaVO3, or V. 13 One or more of O6.

10. The zinc metal battery as described in claim 9, characterized in that, The zinc electrode has a thickness of 30-100 μm, and the organic eutectic gel electrolyte has a thickness of 0.8-1.2 mm.

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