CN118712529A - An electrolyte for zinc ion battery and its preparation method and application - Google Patents

Abstract

The present invention discloses an electrolyte for zinc ion batteries, a preparation method and an application thereof, wherein the electrolyte comprises an electrolyte salt, a co-solvent and water; the co-solvent comprises dipropylene glycol methyl ether. The electrolyte of the present invention adopts dipropylene glycol methyl ether as a co-solvent, which can alleviate the side reactions related to the zinc negative electrode and water, while retaining many advantages of aqueous electrolytes, such as high ionic conductivity and low price. The presence of dipropylene glycol methyl ether can reduce the freezing point of the aqueous electrolyte and inhibit side reactions such as hydrogen evolution at higher temperatures, thereby increasing the operating temperature range of the zinc ion battery and enhancing the potential for all-weather application of the zinc ion battery. In addition, the presence of dipropylene glycol methyl ether also increases the cycle stability and reversibility of the zinc ion battery in a wide temperature range, so that the zinc ion battery containing the electrolyte of the present invention can be stably circulated for a long time in a wide temperature range.

Description

An electrolyte for zinc ion battery and its preparation method and application

Technical Field

The invention belongs to the field of batteries, and in particular relates to an electrolyte for zinc ion batteries and a preparation method and application thereof.

Background Art

Zinc-ion batteries have attracted widespread attention due to their advantages such as high safety, low cost, simple manufacturing process, abundant zinc content in the earth's crust, and a theoretical capacity of up to 820 mAh g ^-1 of zinc metal. However, the occurrence of irregular dendrite growth, hydrogen evolution, corrosion and other side reactions in zinc-ion batteries hinders their long-term reversibility in traditional aqueous electrolytes, especially when zinc-ion batteries work under low or high temperature conditions. The above problems are more serious. Specifically, under low temperature conditions, aqueous electrolytes are prone to freezing, resulting in reduced ion mobility, insufficient wettability to electrodes, and poor electrode/electrolyte interface contact. On the contrary, increased temperature accelerates the thermodynamics and kinetics of the zinc metal anode, resulting in spontaneous corrosion of the zinc anode and increased hydrogen evolution. These factors seriously affect the stability of zinc-ion batteries, resulting in insufficient reversibility and rapid failure of zinc-ion batteries under a wide temperature range. So far, various strategies have been explored to improve the performance of zinc-ion batteries under a wide temperature range. Among them, electrolyte optimization strategy is the simplest and most effective method, such as high entropy electrolytes, high-concentration electrolytes, deep eutectic electrolytes and ionic liquids. Although the current electrolyte optimization strategy can broaden the operating temperature range of zinc-ion batteries to a certain extent, it has disadvantages such as high cost, complex operation, and poor battery performance. It is not conducive to the actual needs of large-scale zinc-ion batteries and limits the development of wide-temperature range zinc-ion batteries.

Summary of the invention

In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide an electrolyte.

A second object of the present invention is to provide a method for preparing the above-mentioned electrolyte.

A third object of the present invention is to provide a zinc ion battery.

A fourth object of the present invention is to provide application of the above-mentioned electrolyte in the field of batteries.

In order to achieve the above object, the technical solution adopted by the present invention is:

The first aspect of the present invention provides an electrolyte solution comprising an electrolyte salt, a co-solvent and water; the co-solvent comprises dipropylene glycol methyl ether.

The cosolvent in the present invention can interact with water, weaken the hydrogen bonding effect between water molecules, destroy the hydrogen bonding network formed between water molecules, and inhibit the activity of water molecules. Since the thermodynamic stability of water mainly depends on the strength of the O-H covalent bond in the water molecule, therefore, weakening the strength of the hydrogen bonding between water molecules in the electrolyte helps to improve the thermodynamic stability of the electrolyte, so that the electrolyte has the effect of low temperature resistance and high temperature resistance, and the zinc ion battery containing the electrolyte can work stably in a wide temperature range. Dipropylene glycol methyl ether has the advantages of good stability, low viscosity, high water solubility and a wide liquid phase temperature range (-80 to 190°C). The addition of dipropylene glycol methyl ether adjusts the solvation structure of zinc ions, enhances the interaction between dipropylene glycol methyl ether and water, and weakens the hydrogen bonding between water molecules, thereby inhibiting the activity of water and improving the thermodynamic stability of the electrolyte. Introducing dipropylene glycol methyl ether into aqueous electrolyte can change the solvation structure of Zn[H ₂ O] ₆ ²⁺ in the aqueous electrolyte. That is, the dipropylene glycol methyl ether co-solvent replaces part of the water to form a new Zn[[H ₂ O] _n [dipropylene glycol methyl ether] _m ] ²⁺ solvation structure and enters the solvation shell of the Zn ²⁺ ion, reducing the activity of water, thereby alleviating the freezing problem of the electrolyte at lower temperatures and side reactions such as hydrogen evolution at higher temperatures. Its application in rechargeable aqueous zinc-based batteries enhances the reversibility and cycle stability of zinc batteries over a wide temperature range.

Preferably, the co-solvent further comprises at least one of propylene glycol methyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether and tripropylene glycol dimethyl ether.

Preferably, the electrolyte salt is selected from zinc salt, lithium salt, sodium salt, calcium salt, magnesium salt, potassium salt. The electrolyte of the present invention can be applied to zinc ion batteries, lithium ion batteries, sodium ion batteries, calcium ion batteries, magnesium ion batteries, potassium ion batteries.

Preferably, the zinc salt is selected from at least one of zinc sulfate, zinc methanesulfonate, zinc trifluoromethanesulfonate, zinc bistrifluoromethanesulfonate imide, zinc chloride, zinc hexafluorosilicate, zinc perchlorate, zinc nitrate, and zinc tetrafluoroborate. The zinc salt in the present invention has high solubility in the electrolyte on the one hand, and does not chemically react with the co-solvent on the other hand.

Preferably, the volume ratio of the cosolvent to water is 1:(0.001-999); further preferably, the volume ratio of the cosolvent to water is 1:(1-10); more preferably, the volume ratio of the cosolvent to water is 1:(1-5).

Preferably, the concentration of the electrolyte salt is 0.5 to 3 mol/L. Within this concentration range, it is beneficial to reduce the cost and viscosity of the electrolyte and make the electrolyte have a higher ion conductivity.

Preferably, the water is deionized water; more preferably, the water is ultrapure water with a resistance of 18 to 25 MΩ.

The second aspect of the present invention provides a method for preparing the electrolyte according to the first aspect of the present invention, comprising the following steps:

The electrolyte salt, water and co-solvent are mixed at 25-60° C. for 8-24 hours to obtain the product.

Under the mixing temperature and mixing time of the present invention, it can be ensured that the electrolyte is mixed uniformly.

The third aspect of the present invention provides a zinc ion battery, comprising the electrolyte described in the first aspect of the present invention.

Preferably, the working temperature of the zinc ion battery is -20°C to 40°C. The zinc ion battery in the present invention can work stably in a wide temperature range of -20°C to 40°C, and has the characteristics of a wide temperature range.

Preferably, the zinc ion battery further comprises an anode, a cathode and a separator.

Preferably, the material of the anode is selected from zinc foil, zinc powder, zinc mesh, and zinc alloy. The anode can achieve reversible insertion and extraction of zinc ions, is low in price, and can be used for large-scale preparation.

Preferably, the thickness of the anode is 1 μm to 100 mm.

Preferably, the cathode material is selected from at least one of vanadium pentoxide, zinc iodide, sodium vanadate, nitrogen-oxygen-containing organic matter, metallic copper, and metallic zinc. The cathode material of the present invention has the advantages of low cost, stable structure, good temperature adaptability, etc.

Preferably, the separator is selected from glass fiber separator, cellulose separator, filter paper, PP separator. The separator is used to separate the anode and cathode materials, and can remain stable during battery charging and discharging in a wide temperature range, and has the advantages of electronic insulation and high ion conductivity.

The fourth aspect of the present invention provides the use of the electrolyte provided by the first aspect of the present invention in the field of batteries.

The beneficial effects of the present invention are as follows: the electrolyte of the present invention uses dipropylene glycol methyl ether as a co-solvent, which can alleviate the side reactions related to the zinc negative electrode and water, while retaining many advantages of aqueous electrolytes, such as high ionic conductivity and low price. The presence of dipropylene glycol methyl ether can reduce the freezing point of the aqueous electrolyte, inhibit side reactions such as hydrogen evolution at higher temperatures, thereby increasing the operating temperature range of the zinc ion battery and enhancing the potential for all-weather application of the zinc ion battery. In addition, the presence of dipropylene glycol methyl ether also increases the cycle stability and reversibility of the zinc ion battery in a wide temperature range, so that the zinc ion battery containing the electrolyte of the present invention can be stably circulated for a long time in a wide temperature range.

The preparation method of the present invention has the characteristics of simple process, low preparation cost, strong repeatability of the preparation process, etc., and is convenient for large-scale production.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the low temperature resistance performance of the electrolytes in Example 1 and Comparative Example 1.

FIG. 2 is a Raman spectrum of the electrolytes in Example 1 and Comparative Example 1.

FIG3 is a graph showing the coulombic efficiency of the zinc ion batteries in Example 3 and Comparative Example 2 at 25° C.

FIG4 is a graph showing the coulombic efficiency of the zinc ion batteries in Example 3 and Comparative Example 2 at -15°C.

FIG5 is a graph showing the coulombic efficiency of the zinc ion batteries in Example 3 and Comparative Example 2 at 40° C.

FIG6 is a long cycle test diagram of the zinc ion battery in Example 4 at -20°C.

FIG. 7 is a long cycle test diagram of the zinc ion battery in Comparative Example 3 at -20°C.

FIG8 is a long cycle test diagram of the zinc ion battery in Example 4 at 25° C.

FIG9 is a long cycle test diagram of the zinc ion battery in Comparative Example 3 at 25° C.

FIG10 is a cross-sectional microscope test image of the zinc negative electrode in the zinc ion battery in Example 4 and Comparative Example 3.

Figure 11 is a DEMS graph of the hydrogen evolution of the zinc ion batteries in Example 4 and Comparative Example 3.

FIG12 is a graph showing the relationship between the mass retention rate of the electrolyte in Example 1 and Comparative Example 1 and time.

FIG13 is a graph showing differential scanning calorimetry results of the electrolytes in Example 1 and Comparative Example 1.

DETAILED DESCRIPTION

The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

Example 1

This example provides an electrolyte for a zinc ion battery, which consists of zinc trifluoromethanesulfonate, dipropylene glycol methyl ether and deionized water. In the electrolyte, the concentration of zinc trifluoromethanesulfonate is 1 mol/L, and the volume ratio of dipropylene glycol methyl ether to deionized water is 1:1.

The electrolyte of the zinc ion battery in this example is prepared by the following preparation method, and the specific steps are as follows:

A certain amount of zinc trifluoromethanesulfonate was dissolved in a mixed solvent of dipropylene glycol methyl ether (2PM, containing ether-based organic matter) and deionized water in a volume ratio of 1:1 to prepare a hybrid electrolyte with a zinc ion concentration of 1 mol/L. The mixture was stirred at 25°C for 10 h to obtain a uniform and stable electrolyte in this example, which was recorded as OTF-2PM50.

Example 2

This example provides an electrolyte for a zinc ion battery, which is composed of zinc trifluoromethanesulfonate, dipropylene glycol methyl ether, tripropylene glycol methyl ether and deionized water. In the electrolyte, the concentration of zinc trifluoromethanesulfonate is 0.5 mol/L, and the volume ratio of dipropylene glycol methyl ether, tripropylene glycol methyl ether and deionized water is 1:1:2.

The electrolyte of the zinc ion battery in this example is prepared by the following preparation method, and the specific steps are as follows:

A certain amount of zinc trifluoromethanesulfonate was dissolved in a mixed solvent of dipropylene glycol methyl ether, tripropylene glycol methyl ether and deionized water in a volume ratio of 1:1:2 to prepare a hybrid electrolyte with a zinc ion concentration of 0.5 mol/L. The mixture was stirred at 50°C for 24 hours to obtain a uniform and stable electrolyte in this example.

Example 3

This example provides a zinc ion battery, the structure of the battery is: a positive electrode shell, a copper foil, an electrolyte, a diaphragm, an electrolyte, a zinc sheet, a gasket, a spring and a negative electrode shell. The electrolyte is the electrolyte of the zinc ion battery in Example 1.

The zinc ion battery in this example is prepared by the following preparation method, and the specific steps are as follows:

Assembled battery: The first type of battery is a zinc-copper battery. The anode and cathode are respectively made of zinc foil and copper foil, the diaphragm is made of glass fiber, and the electrolyte is 110 μL of the electrolyte in Example 1. The battery structure is: positive electrode shell, copper foil, electrolyte, diaphragm, electrolyte, zinc sheet, gasket, shrapnel and negative electrode shell, which are assembled into a CR2032 button battery, recorded as a zinc-copper asymmetric battery.

Example 4

This example provides a zinc ion battery, the structure of the battery is: a positive electrode shell, a zinc sheet, an electrolyte, a diaphragm, an electrolyte, a zinc sheet, a gasket, a spring and a negative electrode shell. The electrolyte is the electrolyte of the zinc ion battery in Example 1.

The zinc ion battery in this example is prepared by the following preparation method, and the specific steps are as follows:

Assemble the battery: zinc sheets are used for both the anode and the cathode, glass fiber is used for the diaphragm, 110 μL of the electrolyte in Example 1 is used as the electrolyte, and the battery structure is as follows: positive electrode shell, zinc sheet, electrolyte, diaphragm, electrolyte, zinc sheet, gasket, shrapnel and negative electrode shell, assembled into a zinc-zinc symmetrical battery.

Comparative Example 1

This example provides an electrolyte for a zinc ion battery, which is composed of zinc trifluoromethanesulfonate and deionized water. In the electrolyte, the concentration of zinc trifluoromethanesulfonate is 1 mol/L.

The electrolyte of the zinc ion battery in this example is prepared by the following preparation method, and the specific steps are as follows:

A certain amount of zinc trifluoromethanesulfonate was dissolved in deionized water to prepare an electrolyte with a zinc ion concentration of 1 mol/L, and stirred at 25° C. for 10 h to obtain a uniform and stable electrolyte in this example, which was recorded as OTF-2PM0.

Comparative Example 2

The zinc ion battery in this example is different from the zinc ion battery in Example 3 only in that this example uses the electrolyte prepared in Comparative Example 1.

Comparative Example 3

The zinc ion battery in this example is different from the zinc ion battery in Example 4 only in that this example uses the electrolyte prepared in Comparative Example 1.

Performance Testing:

The electrolytes prepared in Example 1 and Comparative Example 1 were placed in a low temperature box at -25°C and -10°C for 1h, respectively, and then taken out to observe whether the electrolytes were solidified. The specific test diagram is shown in Figure 1, wherein Figure 1(a) and Figure 1(c) are the actual pictures of the electrolytes prepared in Example 1 and Comparative Example 1 at -25°C, respectively; Figure 1(b) and Figure 1(d) are the actual pictures of the electrolytes prepared in Example 1 and Comparative Example 1 at -10°C, respectively. As can be seen from Figure 1, at -25°C, the electrolyte in Comparative Example 1 has solidified into a solid, while the electrolyte in Example 1 is still a liquid with good fluidity, which further proves that the introduction of ether-containing organic matter into the electrolyte can improve the low temperature resistance of the electrolyte.

The Raman spectra of the electrolytes prepared in Example 1 and Comparative Example 1 were tested respectively, and the specific test results are shown in Figure 2. As shown in Figure 2, compared with Comparative Example 1, after the electrolyte in Example 1 introduced dipropylene glycol methyl ether co-solvent, the OH bond attributable to water at 3100-3700 cm ^-1 was significantly weakened and slightly shifted, indicating that the free water content in the hybrid electrolyte containing the co-solvent was reduced, which helps to broaden the temperature range of the hybrid electrolyte.

The assembled CR2032 button batteries in Example 3 and Comparative Example 2 (OTF-2PM50 in the figure refers to a zinc ion battery using the electrolyte in Example 1, and OTF-2PM0 in the figure refers to a zinc ion battery using the electrolyte in Comparative Example 1, and the meanings of the labels in the figures of the battery test part of the present invention are the same as herein) were tested for coulombic efficiency on a Xinwei battery testing system at low temperature (-15°C), room temperature (25°C) and high temperature (40°C), respectively. The test conditions at 25°C were a current density of 5mA/ ^cm2 and a deposition capacity of 1mAh/ ^cm2 . The performance test graph is shown in FIG3, wherein FIG3(a) is a coulombic efficiency test graph of the batteries in Example 3 and Comparative Example 2, and FIG3(b) is a partial enlarged graph of FIG3(a); the test conditions at -15°C and 40°C were a current density of 1mA/ ^cm2 and a deposition capacity of 0.5mAh/ ^cm2 , and its performance is shown in Figures 4 and 5, respectively, wherein Figure 4(a) is a coulombic efficiency test diagram of the battery in Example 3 and Comparative Example 2, and Figure 4(b) is a partial enlarged diagram of Figure 4(a); Figure 5(a) is a coulombic efficiency test diagram of the battery in Example 3 and Comparative Example 2, and Figure 5(b) is a partial enlarged diagram of Figure 5(a). As can be seen from Figures 3 to 5, the zinc-copper asymmetric battery composed of a hybrid electrolyte containing an ether-based organic substance as a co-solvent in the CR2032 button battery in Example 3 has stable cycle performance over a wide temperature range, indicating that the free water molecules in the electrolyte are fixed, and the water molecules are prevented from aggregating to form ice crystals at low temperatures, and have better cycle stability, specifically: it can stably circulate for more than 400 cycles at -15°C and the average coulombic efficiency is 96.0%, which is significantly higher than the coulombic efficiency of the battery using the electrolyte in Comparative Example 1 (its value is 75.7 ％); it can stably cycle more than 2500 times at 25℃ and the average coulombic efficiency is 97.2%, which is significantly higher than the coulombic efficiency of the battery using the electrolyte in Comparative Example 1 (its value is 56.9%); it can stably cycle more than 150 times at 40℃ and the average coulombic efficiency is 91.0%, which is significantly higher than the coulombic efficiency of the battery using the electrolyte in Comparative Example 1 (its value is 79.0%). The electrolyte composed of the ether-containing organic matter as a co-solvent at high temperature can suppress side reactions such as hydrogen evolution, thereby increasing the reversibility and cycle stability of the battery. The battery in Comparative Example 2 uses the electrolyte in Comparative Example 1, and the prepared zinc ion battery may fail quickly due to freezing of the electrolyte under pure water-based electrolyte.

The long cycle performance of the zinc ion batteries in Example 4 and Comparative Example 3 was tested at a temperature of -20°C, a current density of 1 mA/ ^cm2 , and a deposition capacity of 1 mAh/ ^cm2 , respectively. The specific test diagrams are shown in Figures 6 and 7. As shown in Figures 6 and 7, at -20°C, the zinc ion battery in Comparative Example 3 uses a pure water-based electrolyte and fails quickly when circulated at low temperatures. The zinc ion battery in Example 4 uses an electrolyte composed of an ether-based organic substance as a co-solvent and can be stably circulated for 1500 hours.

The long cycle performance of the zinc ion batteries in Example 4 and Comparative Example 3 was tested at a temperature of 25°C, a current density of 1 mA/ ^cm2 , and a deposition capacity of 1 mAh/ ^cm2 , respectively. The specific test diagrams are shown in Figures 8 and 9, respectively, wherein Figure 8(a) is a long cycle performance test diagram, and Figures 8(b), 8(c), and 8(d) are all partial enlarged diagrams of Figure 8(a). It can be seen from Figures 8 and 9 that at 25°C, the zinc ion battery in Comparative Example 3 uses a pure water-based electrolyte with a cycle time of less than 500 hours, while the zinc ion battery in Example 4 uses an electrolyte composed of an ether-based organic substance as a co-solvent, and has a long cycle stability of more than 4200 hours.

The cross-section of the zinc negative electrode after dynamic zinc deposition of the zinc ion battery in Example 4 and Comparative Example 3 was observed by an in-situ optical microscope at a temperature of 40°C, a current density of 5mA/ ^cm2 , and a deposition capacity of 5mAh/ ^cm2 , respectively. The specific results are shown in Figure 10. As shown in Figure 10, the zinc ion battery in Example 4 uses an electrolyte composed of an ether-based organic substance as a co-solvent, and the zinc nucleation is more intensive, the growth is smoother, and the deposition layer is thin and uniform, while Comparative Example 3 uses a pure water-based electrolyte, and the zinc negative electrode forms protrusions during the deposition process, increases the electrode thickness, and has obvious bubbles, which may be the main cause of battery failure. These electrochemical results prove that the electrolyte composed of an ether-based organic substance as a co-solvent can effectively inhibit side reactions and improve the electrochemical performance of the zinc negative electrode.

The inhibitory effect of the electrolyte of the zinc ion battery in Example 4 and Comparative Example 3 on hydrogen evolution was tested by in situ differential electrochemical mass spectrometry, and the DEMS curve of hydrogen evolution in the zinc-zinc symmetric battery at a temperature of 25°C, a current density of 5 mA/ ^cm2 , and a deposition capacity of 5 mAh/ ^cm2 , and the quantitative differential electrochemical mass spectrometry results of hydrogen evolution during open circuit potential and charge and discharge are shown in Figure 11. As shown in Figure 11, compared with Comparative Example 3, Example 4 uses a hybrid electrolyte containing an ether-based organic substance as a co-solvent, and the hydrogen evolution on the surface of the zinc negative electrode is significantly reduced, which is related to the excellent anti-corrosion ability under open circuit potential conditions and the activity of inhibiting hydrogen evolution.

A 1 mol/L zinc sulfate aqueous solution was prepared, and then the relationship between the mass retention rate and time of Example 1, Comparative Example 1 and the zinc sulfate aqueous solution during open storage under room temperature and atmospheric conditions was tested respectively. The specific test results are shown in Figure 12. As shown in Figure 12, Example 1 uses a hybrid electrolyte composed of an ether-based organic substance as a co-solvent, and the volatility under room temperature and atmospheric conditions is very low. After 120 hours, the electrolyte retains more than 97.4% of its original weight, while Comparative Example 1 uses a 1 mol/L zinc trifluoromethanesulfonate aqueous solution as an electrolyte, which retains 95.9%. When a 1 mol/L zinc sulfate aqueous solution is used as an electrolyte, the weight of the electrolyte is only retained by 92.1%. It can be seen that compared with the zinc sulfate aqueous solution and the zinc trifluoromethanesulfonate aqueous solution, the electrolyte in Example 1 has lower volatility and higher water retention, which is more conducive to the long cycle of the battery.

In addition, the differential scanning calorimetry results of the electrolytes in Example 1 and Comparative Example 1 are shown in FIG13 . As can be seen from FIG13 , the freezing point of the hybrid electrolyte composed of an ether-containing organic substance as a co-solvent in Example 1 is -23.9° C., which is lower than the freezing point of an aqueous solution of zinc trifluoromethanesulfonate with a concentration of 1 mol/L as the electrolyte in Comparative Example 1 (the value is -8.5° C.), further proving that the introduction of an ether-containing organic substance into the electrolyte can improve the low temperature resistance of the electrolyte.

In summary, the electrolyte in the present invention can inhibit the side reaction at the interface between the zinc negative electrode and the electrolyte in the electrolyte, so that the battery containing the electrolyte can be stably cycled for a long time, and can solve the problem of poor reversibility and rapid failure of aqueous zinc-based batteries at low or high temperatures caused by the narrow liquid temperature range of pure aqueous electrolytes. In addition, the electrolyte in the present invention has excellent cycle stability and reversibility, specifically: it can be stably cycled within 1500 hours at a temperature of -20°C, and has a long cycle stability of more than 4200 hours at room temperature.

The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims (10)

1. An electrolyte, characterized in that: comprises electrolyte salt, cosolvent and water; the cosolvent comprises dipropylene glycol methyl ether.

2. The electrolyte of claim 1, wherein: the cosolvent also comprises at least one of propylene glycol methyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether and tripropylene glycol dimethyl ether.

3. The electrolyte of claim 1, wherein: the electrolyte salt is selected from zinc salt, lithium salt, sodium salt, calcium salt, magnesium salt and potassium salt.

4. The electrolyte according to claim 3, wherein: the zinc salt is at least one selected from zinc sulfate, zinc methanesulfonate, zinc trifluoromethane sulfonate, zinc bistrifluoromethane sulfonate imine, zinc chloride, zinc hexafluorosilicate, zinc perchlorate, zinc nitrate and zinc tetrafluoroborate.

5. The electrolyte of claim 1, wherein: the volume ratio of the cosolvent to the water is 1: (0.001-999).

6. The electrolyte of claim 1, wherein: the concentration of the electrolyte salt is 0.5-3 mol/L.

7. The method for producing an electrolyte according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:

The electrolyte salt, water and cosolvent are mixed for 8 to 24 hours at the temperature of 25 to 60 ℃ to prepare the electrolyte.

8. A zinc ion battery characterized in that: comprising the electrolyte according to any one of claims 1 to 6.

9. The zinc-ion battery of claim 8, wherein: the working temperature of the zinc ion battery is-20-40 ℃.

10. Use of the electrolyte according to any one of claims 1 to 6 in the field of batteries.