Composite system high-entropy electrolyte for aqueous zinc ion battery and preparation method of composite system high-entropy electrolyte

Abstract

The invention provides a composite system high-entropy electrolyte for an aqueous zinc ion battery and a preparation method of the composite system high-entropy electrolyte, and belongs to the technical field of aqueous zinc ion batteries. The composite system high-entropy electrolyte comprises a zinc salt, an additive and a solvent, wherein the additive comprises glycerol and tetrahydrofuran. According to the invention, glycerol and tetrahydrofuran are introduced into the electrolyte at the same time, and through the synergistic effect of glycerol and tetrahydrofuran, the cycle stability and cycle life of the battery can be significantly improved, and the polarization voltage during charging and discharging of the battery can be effectively reduced. According to the method for remarkably improving the electrochemical performance of the aqueous zinc ion battery by introducing the additive containing glycerol and tetrahydrofuran into the electrolyte, other complex treatment is not needed, and the method has the advantages of being easy to operate, small in danger, convenient to produce and the like, and industrial large-scale production is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aqueous zinc ion battery, in particular to a composite system high-entropy electrolyte for aqueous zinc ion battery and a preparation method thereof. BACKGROUND

[0002] Under the background of global sustainable energy development and deepening of electrification, electrochemical energy storage technology has become a key research direction in the field of energy. For a long time, lithium ion batteries have occupied a dominant position in portable electronic devices, electric vehicles and some energy storage systems due to their high energy density and mature industrialization system. However, its development faces many bottlenecks: the limited reserves, uneven distribution and high price of lithium metal resources will have an impact on the environment during mining operations; organic electrolyte is flammable and has safety hazards; and so on. Under this situation, aqueous zinc metal battery emerges as a potential alternative technology. Aqueous zinc metal battery uses metal zinc as the negative electrode, and the production of the required materials is rich in resources and low in production cost; the aqueous electrolyte is safe; and the zinc negative electrode has high theoretical capacity and potential to improve energy density. Although aqueous zinc metal battery has many advantages, it still faces a series of difficulties and challenges in practical application. Zinc negative electrode is prone to dendrite growth during charging and discharging, which may pierce the separator and cause short circuit; corrosion and hydrogen evolution reaction (HER) may also occur, consuming active materials, reducing coulombic efficiency, and affecting battery performance and life.

[0003] To solve the above problems, researchers have tried various methods, such as zinc negative electrode surface modification, electrolyte regulation, optimization of battery structure and separator performance, etc., but these methods have limitations such as high cost, complex process, stability to be verified or difficulty in large-scale production. Among them, electrolyte regulation includes the development of electrolyte additives, and existing technologies mostly regulate electrolyte performance through single additives, but it is difficult for single component to simultaneously consider high and low temperature adaptability, ion conduction efficiency and zinc electrode stability.

[0004] At present, multi-solvent high-entropy electrolyte is an effective strategy to stabilize the zinc negative electrode. Through the synergistic effect of various solvent additives such as water, alcohol and ether, the ion solvation structure is obviously regulated, the migration rate is improved, the temperature adaptability is enhanced (such as inhibition of low-temperature icing and enhancement of high-temperature stability), and the electrode interface is optimized to reduce the growth of zinc dendrites, corrosion and side reactions of zinc negative electrode, thereby improving the overall performance of the battery; however, how to accurately regulate the proportion and synergistic effect of solvent additives so that they can overcome the shortcomings of single additives, significantly improve desolvation energy, ion conduction and enhance the electrochemical stability of the electrolyte interface has become the main problem in the field of aqueous zinc metal battery electrolyte. SUMMARY

[0005] In view of the above deficiencies of the prior art, the application provides a composite system high-entropy electrolyte for aqueous zinc ion batteries and a preparation method thereof.The composite system high-entropy electrolyte can effectively inhibit the growth of zinc dendrites and side reactions without affecting the ionic conductivity, and significantly reduce the battery polarization voltage, thereby significantly improving the cycle stability and cycle life of the battery.

[0006] To achieve the above-mentioned purposes, the specific technical solutions of the application are as follows:

[0007] In a first aspect, the application provides a composite system high-entropy electrolyte for aqueous zinc ion batteries, comprising a zinc salt, an additive and a solvent; the additive comprises glycerol and tetrahydrofuran.

[0008] Further, the mass concentration of the additive in the composite system high-entropy electrolyte is 0.02% to 0.07%.

[0009] Further, the volume ratio of the glycerol to tetrahydrofuran is 6: (2-5).

[0010] Further, the concentration of the zinc salt in the composite system high-entropy electrolyte is 1.9-2.2 mol·L -1 .

[0011] Further, the zinc salt comprises zinc sulfate, and the solvent comprises deionized water.

[0012] In a second aspect, the application provides a preparation method of the composite system high-entropy electrolyte for aqueous zinc ion batteries, comprising the following steps: mixing a zinc salt and a solvent to prepare a zinc salt solution with a certain concentration, adding an additive and mixing uniformly to obtain the composite system high-entropy electrolyte for aqueous zinc ion batteries.

[0013] Further, a magnetic stirrer is used to stir at a speed of 60-100 r·min -1 for 30-120 min.

[0014] In a third aspect, the application provides application of the composite system high-entropy electrolyte in aqueous zinc ion batteries.

[0015] The application significantly improves the cycle performance of the aqueous zinc ion battery by introducing a multi-solvent additive including glycerol and tetrahydrofuran into the electrolyte of the aqueous zinc ion battery, and has the advantages of green environmental protection, simple operation and significant effect. Among them, glycerol is a polyhydroxy compound, which can enhance the hydrogen bond network of the electrolyte system, inhibit the content of free water near the negative electrode reaction interface, thereby inhibiting the further occurrence of HER on the negative electrode surface; at the same time, the introduction of glycerol can inhibit the formation of ice crystals at low temperature and improve the anti-freezing property of the electrolyte while improving the viscosity of the electrolyte with little increase. The high-temperature thermal stability of the electrolyte. Tetrahydrofuran has weak solvation characteristics, and when it is introduced into the electrolyte together with glycerol, it can effectively weaken the interaction of Zn 2+ solvation structure ([Zn(H2O)6] 2+ ), reduce the desolvation energy of Zn 2+ , and enhance the diffusion rate of Zn 2+ , thereby promoting the uniform deposition and stripping of zinc ions on the zinc negative electrode surface and improving the reaction interface stability, thereby inhibiting the growth of zinc dendrites. Using deionized water as the solvent ensures the ionic conductivity of the electrolyte, and prevents the performance of the battery from being reduced due to excessively low ionic conductivity. The application of the composite high-entropy electrolyte to the aqueous zinc ion battery can significantly improve the cycle stability and cycle life of the battery, reduce the polarization voltage during charging and discharging of the battery, and enhance the performance of the battery.

[0016] In a fourth aspect, the application provides an aqueous zinc ion battery, comprising a positive electrode, a negative electrode, a separator and the composite high-entropy electrolyte.

[0017] Compared with the prior art, the application has the following advantages:

[0018] (1) The composite high-entropy electrolyte for the aqueous zinc ion battery provided by the application significantly improves the cycle stability of the aqueous zinc ion battery through the synergistic effect of glycerol and tetrahydrofuran in the electrolyte. Among them, glycerol can improve the liquid anti-freezing property and thermal stability, and the viscosity of the electrolyte with the introduction of glycerol is not significantly improved. Tetrahydrofuran has weak solvation characteristics, and when it is introduced into the electrolyte together with glycerol, it can effectively reduce the desolvation energy of Zn 2+ , enhance the diffusion rate of Zn 2+ , thereby promoting the uniform deposition and stripping of Zn 2+ , inhibiting the growth of zinc dendrites, and significantly improving the low-temperature ion migration rate. The application of the composite high-entropy electrolyte to the aqueous zinc ion battery can significantly improve the cycle stability and cycle life of the battery, and effectively reduce the polarization voltage during charging and discharging of the battery.

[0019] (2) The method for significantly improving the electrochemical performance of aqueous zinc ion batteries by introducing an additive comprising glycerol and tetrahydrofuran into an electrolyte solution without other complex treatments has the advantages of simple operation, small danger, convenient production, etc., and is beneficial to industrial scale production.

[0020] (3) The composite system high-entropy electrolyte for aqueous zinc ion batteries can also be applied to zinc-bromine flow batteries and other zinc negative electrode batteries, is compatible with lead-acid battery production lines after application, and is suitable for 48V communication base stations, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 is a Fourier infrared spectrum of WGT-E and WGT in Example 1, wherein a is the Fourier infrared spectrum of WGT-E and WGT, and b is the Raman spectrum of WGT-E and ordinary zinc sulfate solution in Example 1;

[0022] Figure 2 Fig. 2 is the constant current charge-discharge test result of two kinds of Zn / / Zn symmetric batteries in Example 2 at a current density of 10 mA·cm -2 -2; wherein, Figure 2 a is the cycle performance test result of the two kinds of Zn / / Zn symmetric batteries; Figure 2 b is the charge-discharge curve of the Zn / / Zn symmetric battery with WGT-E as the electrolyte at different cycles; Figure 2 c is the charge-discharge curve of the Zn / / Zn symmetric battery with ordinary zinc sulfate as the electrolyte at different cycles;

[0023] Figure 3 Fig. 3 is the constant current charge-discharge test result of four kinds of Zn / / Cu half-batteries in Example 2, Comparative Example 1 and Comparative Example 2 at a current density of 10 mA·cm -2 -2; wherein, Figure 3 a is the cycle performance test result of the four kinds of Zn / / Cu half-batteries; Figure 3 b is the charge-discharge curve of the Zn / / Cu half-battery with WGT-E as the electrolyte at different cycles; Figure 3 c is the charge-discharge curve of the Zn / / Cu half-battery with ordinary zinc sulfate as the electrolyte at different cycles; Figure 3 d is the charge-discharge curve of the Zn / / Cu half-battery with WT-E as the electrolyte at different cycles; Figure 3 e is the charge-discharge curve of the Zn / / Cu half-battery with WG-E as the electrolyte at different cycles.

[0024] Figure 4 Fig. 4 is the constant current charge-discharge test result of two kinds of Zn / / (NH4) x VO3 full batteries in Example 2 at a current density of 10 mA·cm -2 -2; wherein, Figure 4a represents two types of Zn / / (NH4) x Cyclic performance test results of VO3 full batteries; Figure 4 b represents Zn / / (NH4) with WGT-E as the electrolyte. x Charge-discharge curves of VO3 full batteries at different charge / discharge cycles; Figure 4 c represents Zn / / (NH4) using ordinary zinc sulfate as the electrolyte. x Charge-discharge curves of VO3 full batteries at different charge / discharge cycles;

[0025] Figure 5 This refers to Zn / / (NH4) using WGT-E as the electrolyte in Example 2. x CV plots of a full VO3 cell at different scan rates;

[0026] Figure 6 The three Zn / / (NH4) solutions using WGT-E as the electrolyte in Example 2 are examples. x Image of an LED light powered by a VO3 battery connected in series;

[0027] Figure 7 The three Zn / / (NH4) solutions using WGT-E as the electrolyte in Example 2 are examples. x The voltage of a full VO3 cell in series;

[0028] Figure 8 Images of WGT-E, ordinary zinc sulfate, WG-E, and WT-E solutions. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a composite high-entropy electrolyte for aqueous zinc-ion batteries, comprising zinc salt, additives, and solvents; the additives include glycerol and tetrahydrofuran.

[0031] In some examples, the mass concentration of the additive in the high-entropy electrolyte of the composite system is 0.02% to 0.07%.

[0032] In some examples, the volume ratio of glycerol to tetrahydrofuran is 6:(2~5).

[0033] In some examples, the concentration of zinc salt in the high-entropy electrolyte of the composite system is 1.9–2.2 mol·L⁻¹. -1 .

[0034] The method for preparing the composite high-entropy electrolyte for aqueous zinc-ion batteries includes the following steps: mixing zinc salt with a solvent to prepare a zinc salt solution of a certain concentration, adding additives and mixing evenly to obtain the composite high-entropy electrolyte for aqueous zinc-ion batteries.

[0035] In some examples, a magnetic stirrer was used at 60–100 r·min. -1 Mix thoroughly for 30-120 minutes at the specified speed.

[0036] Example 1

[0037] A composite high-entropy electrolyte for aqueous zinc-ion batteries is prepared as follows:

[0038] Glycerol and tetrahydrofuran were mixed evenly at a volume ratio of 6:3.5 to obtain the additive (denoted as WGT).

[0039] Weigh 11.55 g of zinc sulfate heptahydrate solid and add it to 20 mL of deionized water. Stir with a magnetic stirrer at 60 r·min. -1 Stir at high speed for 40 minutes until homogeneous to obtain a 2M zinc sulfate solution (denoted as ordinary zinc sulfate). See the image below. Figure 8 ;

[0040] Additives were added to a standard zinc sulfate solution to achieve a final concentration of 0.04%, and the solution was stirred using a magnetic stirrer at 60 r·min. -1 The mixture was stirred at a certain speed for 40 minutes until homogeneous, yielding a composite high-entropy electrolyte (denoted as WGT-E) for aqueous zinc-ion batteries. See the image below for the actual product. Figure 8 .

[0041] The WGT-E prepared in this embodiment was subjected to Fourier transform infrared spectroscopy, and the WGT-E was subjected to Raman spectroscopy, along with ordinary zinc sulfate. The results are shown in [Figure number missing]. Figure 1 .

[0042] Figure 1 Fourier transform infrared spectroscopy results of a showed that WGT-E and the compounds within WGT corresponded to the CO and OH functional groups and SO4. 2- The absorption peaks of WGT-E and WGT are at 3300 cm⁻¹. -1 The peak at 1060 cm⁻¹ is formed by the stretching vibration of the OH bond, which is related to its presence of water and glycerol functional groups; WGT-E and WGT are at 1060 cm⁻¹. -1 The peak at 1080 cm⁻¹ is formed by the stretching vibration of the CO bond, which is related to the tetrahydrofuran functional group it contains; WGT-E at 1080 cm⁻¹ -1 The peak at that location is due to SO4 2-Internal chemical bonds are formed through stretching vibrations. Figure 1 Raman spectroscopy results for b show that the compound within WGT-E corresponds to the CO and OH functional groups of ordinary zinc sulfate and SO4. 2- The absorption peaks of WGT-E and ordinary zinc sulfate are at 980 cm⁻¹. -1 The peak at that location is due to SO4 2- Internal chemical bond stretching vibrations form; ordinary zinc sulfate at 3500 cm⁻¹ -1 The peak at 3500 cm⁻¹ is formed by the stretching vibration of OH bonds, which is related to its water content; WGT-E at 3500 cm⁻¹ -1 The peak at 1060 cm⁻¹ is formed by the stretching vibration of the OH bond, which is related to the presence of water and glycerol functional groups. Due to the introduction of glycerol, its polyhydroxy structure effectively enhances the hydrogen bond network of the system, reducing the content of free water near the negative electrode reaction interface, thereby inhibiting HER occurring on the zinc negative electrode surface; WGT-E at 1060 cm⁻¹ -1 The peak at that point is formed by the stretching vibration of the CO bond, which is related to the tetrahydrofuran functional group it contains. When tetrahydrofuran and glycerol are introduced into the electrolyte, their weak solvation effect can effectively weaken the Zn content. 2+ The interactions within the solvation structure enhance the diffusion rate of ions, promote the uniform deposition and stripping of zinc ions on the zinc anode surface, and inhibit the growth of zinc dendrites.

[0043] Example 2

[0044] A water-based zinc-ion battery is prepared as follows: The required battery materials are assembled in sequence according to the 2025 model negative electrode shell, negative electrode sheet, separator, electrolyte, positive electrode sheet, gasket, spring sheet, and 2025 model positive electrode shell, and then packaged to obtain the battery.

[0045] 1. Zn / / Zn symmetric cell

[0046] Two Zn / / Zn symmetric cells were assembled using a 12 mm radius zinc sheet as the negative electrode and a 12 mm radius zinc sheet as the positive electrode, respectively, with ordinary zinc sulfate and WGT-E as the electrolyte.

[0047] The two assembled Zn / / Zn symmetric cells were placed on a blue electric field testing system at 10 mA·cm⁻¹. -2 Under the specified current density, constant current charge-discharge tests were conducted in the following sequence: rest, constant current charging, rest, and constant current discharging. The rest time was 30 s for each test, and the constant current charge-discharge time was 0.1 h for each. The test results are as follows: Figure 2 As shown, where, Figure 2 a represents the cycle performance test results of two Zn / / Zn symmetric cells; Figure 2 b represents the charge-discharge curves of a Zn / / Zn symmetric battery with WGT-E as the electrolyte for different numbers of cycles;Figure 2 c represents the charge-discharge curves of a Zn / / Zn symmetric battery with ordinary zinc sulfate as the electrolyte for different numbers of cycles.

[0048] Depend on Figure 2 As can be seen from a, the polarization voltage of the Zn / / Zn symmetric cell using WGT-E as the electrolyte is significantly lower than that of the Zn / / Zn symmetric cell using ordinary zinc sulfate as the electrolyte. This indicates that the Zn / / Zn symmetric cell using WGT-E as the electrolyte has better cycle stability. Figure 2 b、 Figure 2 c shows that the polarization voltage of the Zn / / Zn symmetric cell with WGT-E as the electrolyte is 86 mV, which is significantly lower than the polarization voltage of the Zn / / Zn symmetric cell with ordinary zinc sulfate as the electrolyte (100 mV). Furthermore, the overpotential of the Zn / / Zn symmetric cell with WGT-E as the electrolyte remains stable, exhibiting stable cycle performance. This indicates that using WGT-E as the electrolyte can effectively suppress the growth of zinc dendrites.

[0049] 2. Zn / / Cu half-cell

[0050] Two Zn / / Cu half-cells were assembled using a 12 mm radius zinc sheet as the negative electrode and a 12 mm radius copper sheet as the positive electrode, with ordinary zinc sulfate and WGT-E as the electrolyte, respectively.

[0051] The two assembled Zn / / Cu half-cells were placed on a blue electric field testing system and tested at 10 mA·cm⁻¹. -2 Under the given current density, constant current charge-discharge tests were performed in the following sequence: rest, constant current charging, rest, and constant current discharging. The results are as follows: Figure 3 As shown, where, Figure 3 a shows the cycle performance test results of two Zn / / Cu half-cells using WGT-E and ordinary zinc sulfate as electrolytes, respectively; Figure 3 b represents the charge-discharge curves of a Zn / / Cu half-cell with WGT-E as the electrolyte for different numbers of cycles; Figure 3 c represents the charge-discharge curves of a Zn / / Cu half-cell with ordinary zinc sulfate as the electrolyte for different numbers of cycles.

[0052] Depend on Figure 3 As can be seen from a, the Zn / / Cu half-cell using WGT-E as the electrolyte exhibits high and stable coulombic efficiency, indicating that the cell has better cycle stability. Figure 3 b、 Figure 3c shows that the polarization voltage of the Zn / / Cu half-cell using WGT-E as the electrolyte (85 mV) is significantly lower than that of the Zn / / Cu half-cell using ordinary zinc sulfate as the electrolyte (106 mV), and the capacity plateau is flatter. This proves that the reaction kinetics of the Zn / / Cu half-cell using WGT-E as the electrolyte are superior, and that using WGT-E as the electrolyte allows the Zn on the zinc anode surface to be more readily absorbed. 2+ More uniform deposition or stripping, and significantly reduced zinc dendrite formation, result in more stable cycle performance of the battery.

[0053] 3. Zn / / (NH4) x VO3 full battery

[0054] A zinc sheet with a radius of 15 mm was used as the negative electrode, and a (NH4) electrode with a radius of 12 mm was used as the negative electrode. X Using VO3 as the positive electrode, and with ordinary zinc sulfate and WGT-E as the electrolyte, two types of Zn / / (NH4) were assembled. x VO3 full cell. (NH4) X The VO3 electrode was prepared as follows: 2.34 g of ammonium metavanadate was weighed and dissolved in 250 mL of deionized water. The temperature was kept constant at 70℃, and the mixture was stirred with a magnetic stirrer at 60 r·min. -1 Stir at a constant speed until completely dissolved, then add 10 mmol of thiourea and continue stirring at a constant temperature until homogeneous. Slowly add dilute sulfuric acid to adjust the pH of the solution to less than 2, continue stirring at a constant temperature for 40 min, then raise the temperature to 90℃ and stir for 2.5 h. After the reaction is complete, filter the product, wash it 5 times with deionized water and anhydrous ethanol, and dry it to obtain the positive electrode material. Mix the positive electrode material, acetylene black, and polyvinylidene fluoride at a mass ratio of 7:2:1 and grind them until fine. Add NMP to dissolve the ground powder to obtain a slightly viscous liquid. Coat this liquid onto carbon paper, dry it, and then punch it into a disc with a diameter of 12 mm, which is (NH4). X VO3 film.

[0055] The two Zn / / (NH4) assemblies were then used. x The VO3 full battery was placed on the Blue Electricity testing system and tested at 5 A·g. -1 Constant current charge-discharge tests were conducted within a current density range of 0.4–1.8 V, following the sequence of rest, constant current charging, rest, and constant current discharging. The resting time was 30 s for each test, and the constant current charge-discharge time was 0.1 h for each. The test results are as follows: Figure 4 As shown, Figure 4 a shows that Zn / / (NH4) using WGT-E as the electrolyte x The VO3 battery offers more stable cycling performance, with a higher remaining capacity (108mAh·cm³) after 1000 cycles. -2 ). Figure 4 b、Figure 4 c shows that Zn / / (NH4) using WGT-E as the electrolyte x Voltage curves of VO3 full cells at different cycle numbers compared to those of Zn / / (NH4) using ordinary zinc sulfate as electrolyte. x VO3 full cells have a more pronounced charge and discharge plateau, which decays more slowly with increasing cycle count, maintaining a lower polarization voltage.

[0056] Zn / / (NH4) with WGT-E as electrolyte x CV tests were performed on a full VO3 cell, with scan rates set from 1 to 10 mV·s. -1 Take a portion of the scan rate, and the result is as follows: Figure 5 As shown in the figure, the peak current remains relatively flat with increasing scan rate, and the curve exhibits high symmetry, low separation between oxidation and reduction peaks, and good stability. This indicates that the system possesses high ionic conductivity, high reversibility, and low internal resistance. Even at high scan rates, the capacity remains good, suggesting that this system is beneficial for enhancing ionic conductivity. These results demonstrate that using WGT-E as the electrolyte can significantly improve the mobility of zinc ions in the solution, and the electrode interface reaction is stable and reversible. Simultaneously, it suppresses battery self-discharge, reduces corrosion current, and increases corrosion potential.

[0057] Three Zn / / (NH4) solutions using WGT-E as the electrolyte were compared. x A series connection of VO3 full batteries was used to test whether it could light up an LED after charging, and the voltage was measured. The results are as follows. Figure 6 , Figure 7 As shown, three Zn / / (NH4) solutions using WGT-E as the electrolyte... x When all VO3 batteries are connected in series, they can be charged and discharged normally, and the LED lights will light up normally.

[0058] Example 3

[0059] The composite high-entropy electrolyte system for aqueous zinc-ion batteries provided in this embodiment is basically the same as that in Example 1, except that: after adding additives to ordinary zinc sulfate, a magnetic stirrer is used at 100 r·min. -1 Stir at high speed for 120 minutes to ensure even mixing.

[0060] Example 4

[0061] The aqueous zinc-ion battery provided in this embodiment is basically the same as that in Embodiment 2, except that: the Zn / / Zn symmetrical cell, Zn / / Cu half-cell, and Zn / / (NH4) are assembled using the 2032 model positive and negative electrode shell. xThe VO3 full cell, after assembly, has a standard specification model of 2032. Testing showed that the 2032 full cell prepared in this embodiment exhibits low polarization voltage, good cycle stability, and good cycle life.

[0062] Comparative Example 1

[0063] An aqueous zinc-ion battery is prepared as follows:

[0064] 1. Prepare the electrolyte

[0065] Weigh 11.55 g of zinc sulfate heptahydrate solid and add it to 20 mL of deionized water. Stir with a magnetic stirrer at 60 r·min. -1 Stir at 60 rpm for 40 min until homogeneous to obtain ordinary zinc sulfate; add tetrahydrofuran to the ordinary zinc sulfate to make the final concentration of tetrahydrofuran 0.04%, and stir with a magnetic stirrer at 60 rpm. -1 Stir at a certain speed for 40 minutes to mix until homogeneous, obtaining an electrolyte containing tetrahydrofuran (denoted as WT-E). See the image below. Figure 8 .

[0066] 2. Zn / / Cu half-cell

[0067] A Zn / / Cu half-cell was assembled using a 12 mm radius zinc sheet as the negative electrode, a 12 mm radius copper sheet as the positive electrode, and WT-E as the electrolyte.

[0068] The assembled Zn / / Cu half-cell was placed on the blue electric field testing system and tested at 10 mA·cm⁻¹. -2 Under the given current density, constant current charge-discharge tests were performed in the following sequence: rest, constant current charging, rest, and constant current discharging. The results are as follows: Figure 3 As shown. Comparison Figure 3 b、 Figure 3 As can be seen from d, the polarization voltage of the Zn / / Cu half-cell with WGT-E as electrolyte is 85 mV, while the polarization voltage of the Zn / / Cu half-cell with WT-E as electrolyte is 99 mV. This proves that using WGT-E as electrolyte can significantly improve ionic conductivity, reduce water solvation, and decrease the HER reaction.

[0069] Comparative Example 2

[0070] An aqueous zinc-ion battery is prepared as follows:

[0071] 1. Prepare the electrolyte

[0072] Weigh 11.55 g of zinc sulfate heptahydrate solid and add it to 20 mL of deionized water. Stir with a magnetic stirrer at 60 r·min. -1Stir at 60 rpm for 40 min until homogeneous to obtain ordinary zinc sulfate; add glycerol to the ordinary zinc sulfate to make the final concentration of glycerol 0.04%, and stir with a magnetic stirrer at 60 rpm. -1 Stir at a certain speed for 40 minutes to mix until homogeneous, obtaining an electrolyte containing glycerol (denoted as WG-E). See the image below. Figure 8 .

[0073] 2. Zn / / Cu half-cell

[0074] A Zn / / Cu half-cell was assembled using a 12 mm radius zinc sheet as the negative electrode, a 12 mm radius copper sheet as the positive electrode, and WG-E as the electrolyte.

[0075] The assembled Zn / / Cu half-cell was placed on the blue electric field testing system and tested at 10 mA·cm⁻¹. -2 Under the given current density, constant current charge-discharge tests were performed in the following sequence: rest, constant current charging, rest, and constant current discharging. The results are as follows: Figure 3 As shown. By Figure 3 As can be seen from a, the Zn / / Cu half-cell using WGT-E as the electrolyte exhibits high and stable coulombic efficiency, indicating that the cell is more stable during cycling. (Comparison) Figure 3 b、 Figure 3 As can be seen from the figure, the polarization voltage of the Zn / / Cu half-cell with WGT-E as the electrolyte (85 mV) is significantly lower than that of the half-cell with WG-E as the electrolyte (96 mV). This indicates that WGT-E as the electrolyte can suppress the HER reaction on the zinc anode surface, while promoting the uniform deposition and stripping of zinc ions on the zinc anode surface, improving the stability of the interfacial reaction, and thus suppressing the growth of zinc dendrites.

[0076] In summary, this invention introduces glycerol and tetrahydrofuran simultaneously into the electrolyte. Through the synergistic effect of glycerol and tetrahydrofuran, the battery's cycle stability and cycle life are significantly improved, and the polarization voltage during charging and discharging is effectively reduced. This invention, by introducing additives including glycerol and tetrahydrofuran into the electrolyte to significantly enhance the electrochemical performance of aqueous zinc-ion batteries, requires no other complex processing and has advantages such as simple operation, low risk, and convenient production, making it suitable for large-scale industrial production.

[0077] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A composite high-entropy electrolyte for aqueous zinc-ion batteries, characterized in that, It includes zinc salts, additives, and solvents; the additives include glycerol and tetrahydrofuran.

2. The high-entropy electrolyte for aqueous zinc-ion batteries according to claim 1, characterized in that, The mass concentration of the additive in the high-entropy electrolyte of the composite system is 0.02%~0.07%.

3. The high-entropy electrolyte for aqueous zinc-ion batteries according to claim 2, characterized in that, The volume ratio of glycerol to tetrahydrofuran is 6:(2~5).

4. The high-entropy electrolyte for aqueous zinc-ion batteries according to claim 1, characterized in that, The concentration of zinc salt in the high-entropy electrolyte of the composite system is 1.9~2.2 mol·L⁻¹. -1 .

5. The high-entropy electrolyte for aqueous zinc-ion batteries according to claim 4, characterized in that, The zinc salt includes zinc sulfate, and the solvent includes water.

6. The method for preparing the high-entropy electrolyte of the composite system for aqueous zinc-ion batteries according to any one of claims 1-5, characterized in that, Includes the following steps: Zinc salt and solvent are mixed to prepare a zinc salt solution of a certain concentration. Additives are added and mixed evenly to obtain a composite high-entropy electrolyte for aqueous zinc-ion batteries.

7. The application of the composite system high-entropy electrolyte according to any one of claims 1-5 in an aqueous zinc-ion battery.

8. An aqueous zinc-ion battery, characterized in that, It includes a positive electrode, a negative electrode, a separator, and a high-entropy electrolyte of the composite system as described in any one of claims 1-5.

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