An electrolyte, zinc ion battery and preparation method and application thereof

Abstract

The present invention relates to an electrolyte, a zinc ion battery, and a preparation method and application thereof. The electrolyte comprises a zinc salt and a polyionic liquid; the polyionic liquid is at least one of an imidazole polyionic liquid, a pyridine polyionic liquid, a pyrrolidine polyionic liquid or a piperidine polyionic liquid; and the concentration of the polyionic liquid is 0.02 to 0.2 mol / L. The electrolyte can inhibit the dendrite growth and the generation of "dead zinc" of the negative electrode of the zinc ion battery, thereby improving the cycle stability and battery life of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of zinc ion batteries, and more specifically, to an electrolyte, a zinc ion battery, and a preparation method and application thereof. Background Art

[0002] With the development of industry in today's society, medium and large energy storage devices are constantly emerging. In recent years, a new generation of energy storage devices, such as lithium-sulfur batteries and lithium-air batteries, have received widespread attention. However, the high cost, limited reserves and safety issues of lithium have restricted the development and application of lithium-ion batteries.

[0003] Aqueous zinc-ion batteries are considered to be the best alternative to lithium-ion batteries due to their high theoretical capacity, low cost, high safety, and environmental friendliness. They have received widespread attention and in-depth research in recent years. However, aqueous zinc-ion batteries are still facing huge challenges. Studies have shown that zinc tends to deposit in a dendritic form during the deposition process to form zinc dendrites, which will fall off to form dead zinc when they grow to a certain extent, resulting in the loss of active substances, reduced coulomb efficiency, and even piercing the diaphragm to cause a short circuit. Therefore, dendrite-free zinc deposition is an important way to improve the electrochemical performance of zinc-ion batteries. The Chinese patent entitled "Zinc-Copper Anode and Preparation Method thereof, Zinc-Ion Battery" provides a zinc-copper anode that avoids the formation of zinc dendrites by coating a copper film on a zinc collector. However, since the key is to modify the zinc electrode, the implementation of this technology is inconvenient and its application is subject to certain restrictions.

[0004] Based on the above situation, it is necessary to study technologies that can overcome the problem of zinc dendrites being easily formed in zinc-ion batteries. Summary of the invention

[0005] The primary purpose of the present invention is to overcome the problem of zinc dendrites being easily formed in the above-mentioned existing zinc ion batteries, and to provide an electrolyte. The electrolyte can inhibit the formation of dendrites and "dead zinc" at the negative electrode of the zinc ion battery, thereby improving the cycle stability and battery life of the battery.

[0006] A further object of the present invention is to provide a method for preparing the above electrolyte.

[0007] A further object of the present invention is to provide the use of the above-mentioned electrolyte in the preparation of a zinc ion energy storage device.

[0008] A further object of the present invention is to provide a zinc ion battery.

[0009] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0010] An electrolyte, characterized in that it comprises a zinc salt and a polyionic liquid; the polyionic liquid is at least one of an imidazole polyionic liquid, a pyridine polyionic liquid, a pyrrolidine polyionic liquid or a piperidine polyionic liquid; and the concentration of the polyionic liquid is 0.02-0.2 mol / L.

[0011] The inventors of the present invention have found through multiple studies that adding a specific polyionic liquid to the electrolyte can form a protective layer on the negative electrode during the battery cycle, inhibiting the formation of dendrites and "dead zinc", thereby improving the battery's cycle stability and battery life; and the amount of additives added is small, saving costs, and to a certain extent, can reduce the economic cost of battery use. In addition, since the ionic liquid polymer is added, it can form a functionalized solid electrode-electrolyte interface protective layer with a specific pore size on the surface of the zinc negative electrode that allows zinc ions to migrate and prevents water molecules from transmitting, which can prevent free water from reaching the surface of the zinc negative electrode to cause side reactions, thereby further extending the charge and discharge cycle life of the zinc ion battery.

[0012] In addition, the content of polyionic liquid in the electrolyte is not higher than 0.2 mol / L, otherwise the solid electrode-electrolyte interface protective layer formed is too thick and will block the reaction areas of the positive and negative electrodes, reducing battery performance; the content of polyionic liquid in the electrolyte is not lower than 0.02 mol / L, otherwise an effective protective layer cannot be formed, and the effect of inhibiting dendrite growth and "dead zinc" generation is not obvious.

[0013] That is, the electrolyte of the present invention can inhibit the growth of zinc ion battery dendrites and the generation of "dead zinc", thereby improving the cycle stability and battery life of the battery.

[0014] Preferably, the weight average molecular weight of the polyionic liquid is 30,000-80,000.

[0015] More preferably, the weight average molecular weight of the polyionic liquid is 50,000-60,000.

[0016] Preferably, the imidazole polyionic liquid has a structure as shown in formula (I):

[0017]

[0018] Formula (I),

[0019] Among them, n 1 =150~500, R is an alkyl chain, X is ClO 4 - , NO 3 - , BF 4 - or PF 6- .

[0020] Preferably, the imidazole polyionic liquid is at least one of poly 1-butyl-3-allylimidazole bromide, poly 1-butyl-3-allylimidazole perchlorate, poly 1-butyl-3-allylimidazole nitrate, poly 1-butyl-3-allylimidazole tetrafluoroborate or poly 1-butyl-3-allylimidazole hexafluorophosphate.

[0021] Preferably, the imidazole polyionic liquid is prepared by the following method: adding the imidazole monomer ionic liquid to a solvent, then adding an initiator, and reacting under an inert atmosphere at 70-90° C. for 24-48 h to obtain the imidazole polyionic liquid.

[0022] More preferably, the imidazole monomer ionic liquid is at least one of 1-butyl-3-allylimidazole bromide, 1-butyl-3-allylimidazole perchlorate, 1-butyl-3-allylimidazole nitrate, 1-butyl-3-allylimidazole tetrafluoroborate or 1-butyl-3-allylimidazole hexafluorophosphate.

[0023] More preferably, the solvent is at least one of acetonitrile or ethanol; the initiator is azobisisobutyronitrile (AIBN); and the inert atmosphere is a nitrogen atmosphere.

[0024] Preferably, the pyridine polyionic liquid has a structure as shown in formula (II):

[0025]

[0026] Formula (II),

[0027] Where R is an alkyl chain, n 2 =100~300, Y is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - .

[0028] Preferably, the pyridine polyionic liquid is at least one of poly 1-methyl-4-vinylpyridinium bromide, poly 1-methyl-4-vinylpyridinium perchlorate, poly 1-methyl-4-vinylpyridinium nitrate, poly 1-methyl-4-vinylpyridinium tetrafluoroborate or poly 1-methyl-4-vinylpyridinium hexafluorophosphate.

[0029] Preferably, the pyridine polyionic liquid is prepared by the following method: adding a pyridine monomer ionic liquid to a solvent, then adding an initiator, and reacting for 24 to 48 hours in an inert atmosphere at 70 to 90° C. to obtain the pyridine polyionic liquid.

[0030] More preferably, the pyridine monomer ionic liquid is at least one of 1-methyl-4-vinylpyridinium bromide, 1-methyl-4-vinylpyridinium perchlorate, 1-methyl-4-vinylpyridinium nitrate, 1-methyl-4-vinylpyridinium tetrafluoroborate or 1-methyl-4-vinylpyridinium hexafluorophosphate.

[0031] More preferably, the solvent is at least one of acetonitrile or ethanol; the initiator is azobisisobutyronitrile (AIBN); and the inert atmosphere is a nitrogen atmosphere.

[0032] Preferably, the pyrrolidine polyionic liquid has a structure as shown in formula (III):

[0033]

[0034] Formula (III),

[0035] Among them, n 3 =200~600, Z is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - .

[0036] Preferably, the pyrrolidine-based polyionic liquid is at least one of poly 1-vinylpyrrolidine perchlorate, poly 1-vinylpyrrolidine hexafluorophosphate, poly 1-vinylpyrrolidine tetrafluoroborate or poly 1-vinylpyrrolidine nitrate.

[0037] Pyrrolidine polyionic liquids can be prepared through pyrrolidine monomeric ionic liquids, and the preparation conditions are similar to those of imidazole polyionic liquids.

[0038] Preferably, the piperidine polyionic liquid has a structure as shown in formula (IV):

[0039]

[0040] Formula (IV), where n 4 =150~500, W is ClO 4 - 、NO 3 - , BF 4- or PF 6 - .

[0041] Preferably, the piperidine polyionic liquid is at least one of poly 1-allylpiperidinium perchlorate, poly 1-allylpiperidinium nitrate, poly 1-allylpiperidinium tetrafluoroborate or poly 1-allylpiperidinium hexafluorophosphate.

[0042] Piperidine polyionic liquids can be prepared through piperidine monomer ionic liquids, and the preparation conditions are similar to those of imidazole polyionic liquids.

[0043] Preferably, the solvent of the electrolyte is water.

[0044] Zinc salts commonly used in the art can be used in the present invention.

[0045] Preferably, the zinc salt is at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc bistrifluoromethanesulfonyl imide or zinc trifluoromethanesulfonate.

[0046] Preferably, the concentration of the zinc salt is 1-3 mol / L.

[0047] Preferably, the electrolyte further comprises a manganese salt.

[0048] More preferably, the manganese salt is at least one of manganese sulfate, manganese nitrate or manganese trifluoromethanesulfonate.

[0049] More preferably, the concentration of the manganese salt is 0.1-0.3 mol / L.

[0050] The preparation method of the electrolyte comprises the following steps: dissolving zinc salt and polyionic liquid in a solvent to obtain the electrolyte.

[0051] The use of the above electrolyte in the preparation of a zinc ion energy storage device is also within the protection scope of the present invention.

[0052] Preferably, the zinc ion energy storage device is a zinc ion battery.

[0053] A zinc ion battery comprises the above electrolyte.

[0054] Preferably, it also includes a positive electrode, a negative electrode and a separator.

[0055] More preferably, the positive electrode is a vanadium-based positive electrode; the negative electrode is metallic zinc; and the diaphragm is a glass fiber diaphragm.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The electrolyte of the present invention can inhibit the growth of zinc ion battery dendrites and the generation of "dead zinc", thereby improving the cycle stability and battery life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a comparison diagram of the time-voltage curve of the zinc ion battery of Example 1 and the time-voltage curve of the zinc ion battery of Comparative Example 1.

[0059] Figure 2 It is a SEM image of the negative electrode of the zinc ion battery of Example 1 after charge and discharge tests.

[0060] Figure 3 This is a SEM image of the negative electrode of the zinc ion battery of Comparative Example 1 after charge and discharge tests. DETAILED DESCRIPTION

[0061] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0062] Example 1

[0063] This embodiment provides an electrolyte and a zinc ion battery.

[0064] 1. The preparation method of the electrolyte is as follows:

[0065] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless and transparent electrolyte is prepared; poly 1-butyl-3-allylimidazolium bromide is added, and ultrasonic dispersion is performed to obtain electrolyte 1#. The concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte is 0.1 mol / L.

[0066] Among them, poly 1-butyl-3-allylimidazolium bromide is prepared by the following method: 1-butyl-3-allylimidazolium bromide is added to acetonitrile solvent, and then an initiator azobisisobutyronitrile is added, and the reaction is carried out under a nitrogen atmosphere at 70°C for 24 hours to obtain poly 1-butyl-3-allylimidazolium bromide. The weight average molecular weight of poly 1-butyl-3-allylimidazolium bromide is 60,000.

[0067] 2. The preparation method of zinc ion battery is as follows:

[0068] V 2 O 5, super P Li, and PVDF were weighed in a ratio of 7:2:1, with a total weight of 0.5 g, and then mixed and ground, and then dispersed in N-methylpyrrolidone to obtain a 3% mass fraction of V 2 O 5 Dispersion, stir thoroughly and take 30μLV 2 O 5 The dispersion was dripped onto a carbon cloth with a diameter of 12 mm and dried to obtain a positive electrode; a zinc foil with a diameter of 15 mm and a thickness of 100 μm was used as a negative electrode; a glass fiber with a diameter of 19 mm was used as a diaphragm; 200 μm of electrolyte 1# was evenly dripped onto the glass fiber diaphragm, and then the button battery shell negative electrode, shrapnel, gasket, negative electrode, glass fiber diaphragm, positive electrode, and button battery shell positive electrode were stacked and installed in order to obtain a zinc ion battery.

[0069] Example 2

[0070] This embodiment provides an electrolyte and a zinc ion battery.

[0071] 1. The preparation method of the electrolyte is as follows:

[0072] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless, transparent electrolyte is prepared; poly 1-butyl-3-allylimidazole hexafluorophosphate is added, and ultrasonic dispersion is performed to obtain electrolyte 2#. The concentration of poly 1-butyl-3-allylimidazole hexafluorophosphate in the electrolyte is 0.1 mol / L.

[0073] Among them, poly 1-butyl-3-allylimidazole hexafluorophosphate was prepared by the following method: 1-butyl-3-allylimidazole hexafluorophosphate was added to acetonitrile solvent, and then an initiator azobisisobutyronitrile was added, and the reaction was carried out under a nitrogen atmosphere at 70°C for 24 hours to obtain poly 1-butyl-3-allylimidazole hexafluorophosphate. The weight average molecular weight of poly 1-butyl-3-allylimidazole hexafluorophosphate is 50,000.

[0074] 2. The zinc ion battery of this embodiment is different from the zinc ion battery of Example 1 in that: the electrolyte 1# of Example 1 is replaced by electrolyte 2#.

[0075] Example 3

[0076] This embodiment provides an electrolyte and a zinc ion battery.

[0077] 1. The preparation method of the electrolyte is as follows:

[0078] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless and transparent electrolyte was prepared; poly 1-methyl-4-vinylpyridine tetrafluoroborate was added, and ultrasonic dispersion was performed to obtain electrolyte 3#. The concentration of poly 1-methyl-4-vinylpyridine tetrafluoroborate in the electrolyte was 0.1 mol / L.

[0079] Among them, poly 1-methyl-4-vinylpyridine tetrafluoroborate was prepared by the following method: 1-methyl-4-vinylpyridine tetrafluoroborate was added to acetonitrile, and then an initiator azobisisobutyronitrile was added, and the reaction was carried out under a nitrogen atmosphere at 70°C for 24 hours to obtain poly 1-methyl-4-vinylpyridine tetrafluoroborate. The weight average molecular weight of poly 1-methyl-4-vinylpyridine tetrafluoroborate was 50,000.

[0080] 2. The zinc ion battery of this embodiment is different from the zinc ion battery of Example 1 in that: the electrolyte 1# of Example 1 is replaced by electrolyte 3#.

[0081] Example 4

[0082] This embodiment provides an electrolyte and a zinc ion battery.

[0083] 1. The preparation method of the electrolyte is as follows:

[0084] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless and transparent electrolyte was prepared; poly 1-methyl-4-vinylpyridine chloride was added and ultrasonically dispersed to obtain electrolyte 4#. The concentration of poly 1-methyl-4-vinylpyridine chloride in the electrolyte was 0.1 mol / L.

[0085] Among them, poly 1-methyl-4-vinylpyridine chloride can be prepared by the following method: 1-methyl-4-vinylpyridine chloride is added to acetonitrile solvent, and then an initiator azobisisobutyronitrile is added, and the reaction is carried out under a nitrogen atmosphere at 70° C. for 24 hours to obtain poly 1-methyl-4-vinylpyridine chloride. The weight average molecular weight of poly 1-methyl-4-vinylpyridine chloride is 60,000.

[0086] 2. The difference between the zinc ion battery of this embodiment and the zinc ion battery of embodiment 1 is that the electrolyte 1# of embodiment 1 is replaced by electrolyte 4#.

[0087] Example 5

[0088] This embodiment provides an electrolyte and a zinc ion battery.

[0089] 1. The preparation method of the electrolyte is as follows:

[0090] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless and transparent electrolyte was prepared; poly 1-butyl-3-allylimidazolium bromide was added, and ultrasonic dispersion was performed to obtain electrolyte 5#. The concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte was 0.1 mol / L.

[0091] Among them, poly 1-butyl-3-allylimidazolium bromide is prepared by the following method: 1-butyl-3-allylimidazolium bromide is added to acetonitrile solvent, and then an initiator azobisisobutyronitrile is added, and the reaction is carried out under a nitrogen atmosphere at 50°C for 4 hours to obtain poly 1-butyl-3-allylimidazolium bromide. The weight average molecular weight of poly 1-butyl-3-allylimidazolium bromide is 30,000.

[0092] 2. The zinc ion battery of this embodiment is different from the zinc ion battery of Example 1 in that: the electrolyte 1# of Example 1 is replaced by electrolyte 5#.

[0093] Example 6

[0094] This embodiment provides an electrolyte and a zinc ion battery.

[0095] 1. The electrolyte of this embodiment is recorded as electrolyte 6#, which is different from electrolyte 1# of embodiment 1 in that the concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte is 0.02 mol / L.

[0096] 2. The zinc ion battery of this comparative example is different from the zinc ion battery of Example 1 in that: the electrolyte 1# of Example 1 is replaced by electrolyte 6#.

[0097] Example 7

[0098] This embodiment provides an electrolyte and a zinc ion battery.

[0099] 1. The electrolyte of this embodiment is recorded as electrolyte 7#, which is different from electrolyte 1# of embodiment 1 in that the concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte is 0.2 mol / L.

[0100] 2. The difference between the zinc ion battery of this comparative example and the zinc ion battery of Example 1 is that the electrolyte 1# of Example 1 is replaced by electrolyte 7#.

[0101] Comparative Example 1

[0102] This comparative example provides a comparative electrolyte and a zinc ion battery.

[0103] 1. The preparation method of the electrolyte is as follows:

[0104] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in deionized water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 The clear, colorless and transparent electrolyte was used as the comparison electrolyte 1#.

[0105] 2. The zinc ion battery of this comparative example is different from the zinc ion battery of Example 1 in that the electrolyte 1# of Example 1 is replaced with the comparative electrolyte 1#.

[0106] Comparative Example 2

[0107] This comparative example provides a comparative electrolyte and a zinc ion battery.

[0108] 1. The comparative electrolyte of this comparative example is recorded as comparative electrolyte 2#, which is different from electrolyte 1# of Example 1 in that the concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte is 0.01 mol / L.

[0109] 2. The zinc ion battery of this comparative example is different from the zinc ion battery of Example 1 in that the electrolyte 1# of Example 1 is replaced by the comparative electrolyte 2#.

[0110] Comparative Example 3

[0111] This comparative example provides a comparative electrolyte and a zinc ion battery.

[0112] 1. The comparative electrolyte of this comparative example is recorded as comparative electrolyte 3#, which is different from electrolyte 1# of Example 1 in that the concentration of poly 1-butyl-3-allylimidazolium bromide in the electrolyte is 0.4 mol / L.

[0113] 2. The zinc ion battery of this comparative example is different from the zinc ion battery of Example 1 in that the electrolyte 1# of Example 1 is replaced with comparative electrolyte 3#.

[0114] Comparative Example 4

[0115] This comparative example provides a comparative electrolyte and a zinc ion battery.

[0116] 1. The preparation method of the electrolyte is as follows:

[0117] Dissolve zinc bis(trifluoromethanesulfonate) and manganese sulfate in pure water to prepare 2 mol / L Zn(CF 3 SO 3 ) 2 and 0.2 mol / L MnSO 4 A clear, colorless, transparent electrolyte was prepared; 1-butyl-3-allylimidazolium bromide was added, and ultrasonic dispersion was performed to obtain a comparative electrolyte 4#. The concentration of 1-butyl-3-allylimidazolium bromide in the electrolyte was 0.1 mol / L.

[0118] 2. The zinc ion battery of this comparative example is different from the zinc ion battery of Example 1 in that the electrolyte 1# of Example 1 is replaced by the comparative electrolyte 4#.

[0119] Performance Testing

[0120] (1) Take the zinc ion batteries of each embodiment and comparative example, let them stand for two hours, and then -2 The zinc ion batteries of each embodiment and comparative example were charged and discharged at a current density of . The test results are shown in Table 1 below:

[0121] Table 1 Charge and discharge test results of various embodiments and comparative examples

[0122]

[0123] As can be seen from Table 1, the zinc ion batteries of Examples 1 to 7 have a longer cycle life, indicating that adding a certain amount of polyionic liquid electrolyte can inhibit the dendrite growth and the generation of "dead zinc" at the negative electrode of the zinc ion battery, thereby improving the cycle stability and battery life of the battery.

[0124] Figure 1 1 is a time-voltage curve comparison diagram of the zinc ion battery of Example 1 and the time-voltage curve comparison diagram of the zinc ion battery of Comparative Example 1, wherein: Figure 1 The gray area in the figure is the charge-discharge time-voltage curve of the zinc ion battery of Example 1, and the dark black area is the charge-discharge time-voltage curve of the zinc ion battery of Comparative Example 1. Figure 1 It can be seen that the zinc ion battery of Comparative Example 1 short-circuited after 30 hours, while the cycle stability of the zinc ion battery of Example 1 was significantly improved, and its cycle life could reach 2010 hours.

[0125] (2) After the charge and discharge test in step (1), the zinc ion battery of Example 1 and the zinc ion battery of Comparative Example 1 were disassembled, and the negative electrode was taken out for SEM electron microscope photography. The SEM image of the negative electrode of the zinc ion battery of Example 1 is as follows: Figure 2 As shown, the SEM image of the negative electrode of the zinc ion battery of Comparative Example 1 is as follows Figure 3 As shown. Figure 2 It can be seen that the negative electrode of the zinc ion battery of Example 1 is dense and has no obvious dendrites, indicating that the addition of polyionic liquid can protect the zinc negative electrode to a certain extent and avoid serious corrosion of the zinc negative electrode. Figure 3 It can be seen that the negative electrode surface of the zinc ion battery of Comparative Example 1 is rough, dendrite growth is serious, the zinc negative electrode of the zinc ion battery is severely corroded, and the cycle life is short.

[0126] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A zinc ion battery electrolyte, It is characterized in that The invention comprises a zinc salt and a polyionic liquid; the polyionic liquid is at least one of an imidazole polyionic liquid, a pyridine polyionic liquid, a pyrrolidine polyionic liquid or a piperidine polyionic liquid; and the concentration of the polyionic liquid is 0.02-0.2 mol / L; The imidazole polyionic liquid has a structure as shown in formula (I): Formula (I), Among them, n 1 =150~500, R is an alkyl chain, X is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - The pyridine polyionic liquid has a structure as shown in formula (II): Formula (II), Among them, n 2 =100~300, R is an alkyl chain, Y is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - The pyrrolidine polyionic liquid has a structure as shown in formula (III): Formula (III), Among them, n 3 =200~600, Z is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - The piperidine polyionic liquid has a structure as shown in formula (IV): Formula (IV), Among them, n 4 =150~500, W is ClO 4 - 、NO 3 - , BF 4 - or PF 6 - .

2. The zinc ion battery electrolyte according to claim 1, It is characterized in that The weight average molecular weight of the polyionic liquid is 30,000-80,000.

3. The zinc ion battery electrolyte according to claim 1, It is characterized in that The concentration of the zinc salt is 1-3 mol / L.

4. The method for preparing the zinc ion battery electrolyte according to any one of claims 1 to 3, It is characterized in that The method comprises the following steps: dissolving zinc salt and polyionic liquid in a solvent to obtain the zinc ion battery electrolyte.

5. Use of the zinc ion battery electrolyte according to any one of claims 1 to 3 in the preparation of a zinc ion energy storage device.

6. A zinc ion battery, It is characterized in that Comprising the zinc ion battery electrolyte described in any one of claims 1 to 3.

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