High-entropy electrolyte, preparation method and application thereof

Abstract

The application relates to the technical field of zinc ion batteries, in particular to a high-entropy electrolyte and a preparation method and application thereof, which comprises deionized water, an organic solvent, a zinc salt and an additive, the organic solvent comprises any one or more of acetonitrile, pyridine, diethylenetriamine, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol, glycerol, n-butanol and butanediol; and the additive comprises a combination of any one or more of sodium hydroxyethyl cellulose, sodium benzoate, methylene bisnaphthalene sulfonate sodium, sodium citrate, sodium gluconate, sodium polyacrylate, sodium carboxymethyl cellulose and sodium hydroxypropyl cellulose. Compared with a conventional electrolyte, the high-entropy electrolyte has multi-dimensional adjustment capability in terms of freezing point adjustment, electrochemical stability and interface structure optimization, exhibits superior comprehensive performance, effectively solves the problem of poor performance of a low-temperature aqueous zinc ion battery in the prior art, and significantly improves the low-temperature adaptability and service life of the battery.

Description

TECHNICAL FIELD

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

[0002] Under low-temperature conditions, the electrolyte of the battery will have a series of problems such as increased viscosity, decreased conductivity, increased impedance of the SEI film, and decreased speed of lithium ions passing through the electrode / electrolyte interface, ultimately leading to rapid decline in battery performance, and even complete failure. Existing research data shows that the discharge capacity of a battery using a conventional commercial electrolyte at-30℃ is only about 50% of that at room temperature, and the battery is basically inoperable at-40℃.

[0003] Therefore, it is an important problem to be solved to develop an electrolyte that can be used in a low-temperature environment and improve the low-temperature performance of the battery, thereby promoting the application and development of the battery.

[0004] In the field of battery systems, a conventional electrolyte is usually composed of a single organic solvent and a dissolved salt. However, such a conventional electrolyte has problems of freezing and decreased electrochemical performance under low-temperature conditions.

[0005] Chinese patent CN 116315159A discloses a novel aqueous zinc ion battery electrolyte, which is prepared by using a soluble zinc salt as an electrolyte salt, a water-soluble organic compound as an additive, and high-purity deionized water as a solvent. The water-soluble organic compound is cyclohexanehexol. The additive cyclohexanehexol molecule itself contains a large number of polar hydroxyl groups, which have strong electron cloud density, so that they not only have strong zinc affinity, but also can directionally control the hydrogen bond network constructed by water molecules in the electrolyte. Therefore, it can greatly limit the activity of water molecules in the electrolyte, thereby inhibiting the occurrence of hydrogen evolution and corrosion reactions; at the same time, it can also homogenize and accelerate the transmission of zinc ions, reduce ion concentration polarization and local current density distribution, thereby preventing the formation and growth of dendrites, solving the problems of arbitrary zinc dendrite growth and serious hydrogen evolution corrosion side reactions, and improving the long-cycle stability of the aqueous zinc ion battery. However, the salt cannot be completely dissolved in the solvent (solubility).

[0006] Chinese invention patent CN 117199553 A discloses a low-temperature aqueous zinc ion battery high-entropy electrolyte, which comprises zinc salt, additive and water; wherein the additive comprises three to four of dimethyl sulfoxide, ethylene glycol, ethyl acetate and N,N-dimethylformamide. Although it is proposed that by reducing the Gibbs free energy and freezing point, the electrolyte can be prevented from freezing in a low-temperature environment, the ionic conductivity of the electrolyte in a low-temperature environment is improved, so that the zinc ion battery can work normally in a low-temperature environment. However, due to the excessive number of components or the performance of organic molecules themselves, there is an organic-water phase separation problem.

[0007] In view of this, the present application is proposed. SUMMARY

[0008] The first object of the present application is to provide a high-entropy electrolyte which significantly improves the low-temperature adaptability and service life of the battery.

[0009] The second object of the present application is to provide a preparation method and application of a high-entropy electrolyte, which is simple and easy to promote on a large scale, provides a new solution for the development of low-temperature energy storage technology, has important social significance, and is particularly important in energy storage and application in extremely cold areas and special environments.

[0010] In a first aspect, the present application provides a high-entropy electrolyte comprising deionized water, an organic solvent, a zinc salt and an additive,

[0011] The organic solvent comprises any one or more of acetonitrile, pyridine, diethylene triamine, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol, glycerol, n-butanol and butanediol, and is preferably acetonitrile, diethylene triamine, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), ethylene glycol and glycerol (glycerol).

[0012] The additive comprises a combination of any one or more of sodium hydroxyethyl cellulose, sodium benzoate, methylene bis naphthalene sulfonate sodium, sodium citrate, sodium gluconate, sodium polyacrylate, sodium carboxymethyl cellulose and sodium hydroxypropyl cellulose, and is preferably sodium citrate and sodium hydroxypropyl cellulose. In the high-entropy electrolyte, the concentration of sodium salt is preferably 0.1-2 mol / L.

[0013] The high-entropy electrolyte of the present application effectively improves the anti-freezing performance of the electrolyte at low temperature, promotes the uniform deposition and dissolution of zinc ions on the surface of the zinc negative electrode, and effectively inhibits the formation and excessive growth of zinc dendrites. The introduction of multiple organic molecules and inorganic / organic salts into water can reduce the freezing point of the electrolyte and enhance the anti-freezing performance in low-temperature environments. At the same time, these additives can also effectively inhibit the formation and growth of ice crystals, ensuring the reliable operation of the battery at extreme temperatures. In the entropy-driven mixed electrolyte system, the hydrogen bonds in the electrolyte are reduced, resulting in the inhibition of hydrogen evolution and a lower overpotential for zinc deposition. The introduction of multiple organic molecules and inorganic / organic salts promotes the participation of organic molecules in the solvation structure, increases the configurational entropy of the electrolyte, and realizes the rapid migration of zinc ions, thereby reducing the overpotential for zinc deposition, especially at low temperatures. The electrolyte system uses organic small molecules containing functional groups such as hydroxyl and amino groups as solvents for the electrolyte, which can effectively form complexes with zinc ions, facilitating the uniform deposition and dissolution of zinc on the electrode surface and improving the performance and stability of the battery. The selection of different organic molecules effectively regulates the activity of free water in the electrolyte, reducing the electrochemical side reactions and solid-liquid interface reactions on the surface of the zinc electrode, which effectively solves the problems of zinc corrosion and electrode passivation, and improves the long-term stability and cycle life of the battery.

[0014] Among them, the organic solvent molecules selected have good water solubility. In the entropy-driven mixed electrolyte, the hydrogen bonds in the electrolyte are reduced, the activity of free water is reduced, thereby inhibiting the side reactions on the surface of the zinc negative electrode, and effectively reducing the corrosion and passivation problems of the zinc negative electrode. Therefore, the high-entropy electrolyte also significantly improves the rate performance and cycle performance of the aqueous zinc ion battery.

[0015] The addition of additives can further optimize the solvation structure and electrochemical performance of the high-entropy electrolyte. Specifically, the additive of the present application is an amphiphilic chemical that can increase the compatibility of oily and aqueous components in the same system and replace water molecules to participate in the solvation structure to form a stable organic layer to support zinc ion transport and inhibit the reducibility of water.

[0016] As a preferred embodiment of the present application, the zinc salt includes any one or a combination of zinc sulfate, zinc nitrate, zinc perchlorate, zinc dihydrogen phosphate, zinc chloride, and zinc triflate, and is preferably zinc sulfate and zinc triflate.

[0017] As a preferred embodiment of the present application, the volume fraction of the organic solvent in the high-entropy electrolyte is 0.1% to 20%, and is preferably 0.1% to 10%.

[0018] As a preferred embodiment of the present application, the concentration of the additive in the high-entropy electrolyte is 0.01 to 3 mol / L, and is preferably 0.1 to 2 mol / L.

[0019] As the preferred technical solution, the concentration of the zinc salt in the high-entropy electrolyte is 0.1-10 mol / L, and preferably 1-5 mol / L.

[0020] As the preferred technical solution, the pH value of the high-entropy electrolyte is 4-8, and preferably 5-8.

[0021] In a second aspect, the application also discloses a preparation method of the high-entropy electrolyte, which also belongs to the protection scope of the application, and specifically comprises the following steps:

[0022] S1, a certain amount of deionized water is taken as a base solution;

[0023] S2, zinc salt is added to the base solution, and under stirring conditions, it is ensured that it is completely dissolved to obtain an aqueous solution of zinc salt;

[0024] S3, one or more organic solvents are added to the aqueous solution of zinc salt, and mixed uniformly to obtain a high-entropy organic solvent mixture;

[0025] S4, an additive is added to the high-entropy organic solvent mixture, and mixed uniformly to obtain a high-entropy electrolyte.

[0026] As the preferred technical solution, the high-entropy electrolyte that is mixed uniformly is further filtered to remove insoluble substances and impurities to obtain a clear high-entropy electrolyte.

[0027] In a third aspect, the application also discloses an application of the high-entropy electrolyte in a water-based zinc ion battery or a zinc ion electrochemical energy storage device, which also belongs to the protection scope of the application.

[0028] The high-entropy electrolyte of the application significantly improves the cycle life and stability of the battery under low temperature conditions, reduces the frequency of battery replacement and maintenance, and reduces the use and maintenance costs, providing a new solution for the development of low-temperature energy storage technology, which has important social significance, especially in the energy storage and application in extremely cold areas and special environments.

[0029] In a fourth aspect, the application also discloses a water-based zinc ion battery, which specifically comprises a positive electrode, a negative electrode, a separator and the high-entropy electrolyte, and also belongs to the protection scope of the application.

[0030] The high-entropy electrolyte of the application significantly improves the cycle life and stability of the battery under low temperature conditions, reduces the frequency of battery replacement and maintenance, and reduces the use and maintenance costs. In addition, the various organic solvents and zinc salts used in the high-entropy electrolyte of the application are common and low-cost raw materials, and the overall economic benefits are high.

[0031] The high-entropy electrolyte of the application has at least the following beneficial effects:

[0032] The high-entropy electrolyte of the present application comprises deionized water, an organic solvent, a zinc salt, and an additive, wherein the organic solvent comprises any one or more of acetonitrile, pyridine, diethylenetriamine, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol, glycerol, n-butanol, and butanediol; the additive comprises a combination of any one or more of sodium hydroxyethyl cellulose, sodium benzoate, sodium methylene bisnaphthalene sulfonate, sodium citrate, sodium gluconate, sodium polyacrylate, sodium carboxymethyl cellulose, and sodium hydroxypropyl cellulose. In the high-entropy electrolyte of the present application, first, a plurality of organic molecules and inorganic / organic salts are used to replace water molecules to form a high-entropy solvation sheath, effectively adjusting the solvation structure and electrochemical reaction; wherein the high-entropy solvation sheath is formed by a plurality of organic molecules in coordination, which can weaken the influence of water molecules on zinc ions and inhibit hydrogen evolution and dendrite growth; on the surface of the zinc negative electrode, organic molecules and zinc ions are preferentially adsorbed to form a deposition interface layer rich in a plurality of organic components, further inhibiting the hydrogen evolution reaction; using the thermodynamic equation, by increasing the configurational entropy to reduce the Gibbs free energy of the electrolyte, the freezing point of the electrolyte can be significantly reduced. Second, by forming a coordination complex between the organic molecules and the zinc ions, the stability and ionic conductivity of the solvation sheath can be significantly enhanced; wherein a plurality of organic molecules (such as pyridine and diethylenetriamine) replace water molecules to participate in the solvation structure, which can form a stable organic layer to support zinc ion transmission and inhibit water reduction reaction; the multi-component organic layer formed at the zinc negative electrode interface can improve the cycle stability of the electrolyte, thereby preventing the electrolyte from drying out and interface corrosion. Finally, the high-entropy electrolyte of the present application significantly improves the ionic mobility and cycle stability of the electrolyte at low temperature through the synergistic effect of the multi-component organic molecules; for example, at -25℃, the Zn||MnO2 battery exhibits excellent ionic mobility and conductivity, and inhibits the restriction of the hydrogen bond-strengthened network structure on the ionic migration path; in the high-entropy electrolyte, the Zn||MnO2 battery can maintain 10,000 cycles at -25℃, with a capacity retention rate of 91.75% and a coulombic efficiency close to 100%. Therefore, the high-entropy electrolyte of the present application effectively solves the problem of poor performance of the low-temperature aqueous zinc ion battery in the prior art, significantly improving the low-temperature adaptability and service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed in the following specific embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0034] Figure 1 State diagram of the electrolyte of the present application Comparative Example 1 (left) and Example 3 (right) at -25℃;

[0035] Figure 2 State diagram of electrolyte of the present application Comparative Example 1 (left) and Example 3 (right) at -30°C;

[0036] Figure 3 Long-term cycling stability of Zn metal anode in electrolyte of the present application Example 1-3;

[0037] Figure 4 Discharge curves of Zn||Mn02 button cell cycled at different current densities at -25°C in electrolyte of the present application Example 3 and Comparative Example 1;

[0038] Figure 5 Long-term cycling stability of Zn metal anode in electrolyte of the present application Comparative Example 2;

[0039] Figure 6 Long-term cycling stability of Zn metal anode in electrolyte of the present application Comparative Example 3;

[0040] Figure 7 Long-term cycling stability of Zn metal anode in electrolyte of the present application Example 4;

[0041] Figure 8 Long-term cycling stability of Zn metal anode in electrolyte of the present application Example 5;

[0042] Figure 9 Scanning electron microscope comparison of zinc negative electrode surface after cycling of aqueous zinc ion symmetric button cell assembled in the present application Comparative Example 5 (left) and Example 5 (right);

[0043] Figure 10 LSV plot of electrolyte in the present application Comparative Example 5 and Example 5;

[0044] Figure 11 LSV plot of electrolyte in the present application Comparative Example 3, Example 1, Example 2 and Example 3;

[0045] Figure 12 Electrochemical impedance plot of electrolyte in the present application Comparative Example 3, Example 1, Example 2 and Example 3. DETAILED DESCRIPTION

[0046] It should be noted that the following detailed description is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0047] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0048] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0049] Embodiment 1

[0050] S1, take 1 mL of deionized water as a base solution;

[0051] S2, add 2 mol / L zinc triflate to the base solution to obtain a zinc salt aqueous solution;

[0052] S3, add 3%vol acetonitrile (ACN) to the zinc salt aqueous solution, mix uniformly to obtain an organic solvent mixture;

[0053] S4, add 0.1 mol / L sodium citrate, 0.1 mol / L sodium gluconate and 0.1 mol / L sodium benzoate to the organic solvent mixture, mix uniformly, filter and remove impurities to obtain a high-entropy electrolyte.

[0054] Embodiment 2

[0055] S1, take 1 mL of deionized water as a base solution;

[0056] S2, add 2 mol / L zinc triflate to the base solution to obtain a zinc salt aqueous solution;

[0057] S3, add 3%vol acetonitrile (ACN) and 1%vol pyridine (Py) to the zinc salt aqueous solution, mix uniformly to obtain an organic solvent mixture;

[0058] S4, add 0.1 mol / L sodium hydroxyethyl cellulose and 0.1 mol / L sodium gluconate to the organic solvent mixture, mix uniformly, filter and remove impurities to obtain a high-entropy electrolyte.

[0059] Embodiment 3

[0060] S1, take 1 mL of deionized water as a base solution;

[0061] S2, add 2 mol / L zinc triflate to the base solution to obtain an aqueous zinc salt solution;

[0062] S3, add 3%vol acetonitrile (ACN), 1%vol pyridine (Py) and 1%vol diethylene triamine (DTA) to the aqueous zinc salt solution, mix well to obtain an organic solvent mixture;

[0063] S4, add 0.1 mol / L sodium hydroxypropyl cellulose and 0.1 mol / L sodium gluconate to the organic solvent mixture, mix well, filter and remove impurities to obtain a high-entropy electrolyte.

[0064] Example 4

[0065] S1, take 1ml deionized water as a base solution;

[0066] S2, add 2 mol / L zinc sulfate to the base solution to obtain an aqueous zinc salt solution;

[0067] S3, add 1%vol N,N-dimethylformamide and 5%vol ethylene glycol to the aqueous zinc salt solution, mix well to obtain an organic solvent mixture;

[0068] S4, add 0.1 mol / L sodium benzoate and 0.1 mol / L sodium gluconate to the organic solvent mixture, mix well, filter and remove impurities to obtain a high-entropy electrolyte.

[0069] Example 5

[0070] S1, take 1mL deionized water as a base solution;

[0071] S2, add 2 mol / L zinc sulfate to the base solution to obtain an aqueous zinc salt solution;

[0072] S3, add 0.5%vol diethylene triamine and 8%vol N,N-dimethylformamide to the aqueous zinc salt solution, mix well to obtain an organic solvent mixture;

[0073] S4, add 0.1 mol / L sodium benzoate and 0.1 mol / L sodium gluconate to the organic solvent mixture, mix well, filter and remove impurities to obtain a high-entropy electrolyte.

[0074] Example 6

[0075] S1, take 1mL deionized water as a base solution;

[0076] S2, add 2 mol / L zinc nitrate to the base solution to obtain an aqueous zinc salt solution;

[0077] S3, 1% vol LN,N-dimethylacetamide and 5% vol glycerol were added to the aqueous solution of zinc salt, and mixed uniformly to obtain an organic solvent mixture;

[0078] S4, 0.1 mol / L sodium benzoate and 0.1 mol / L sodium gluconate were added to the organic solvent mixture and mixed uniformly, and the high-entropy electrolyte was obtained after filtration and impurity removal.

[0079] Example 7

[0080] S1, 1 mL of deionized water was taken as a base solution;

[0081] S2, 1 mol / L zinc nitrate was added to the base solution to obtain an aqueous solution of zinc salt;

[0082] S3, 5% vol N-dimethylformamide, 5% vol ethylene glycol and 1% vol glycerol were added to the aqueous solution of zinc salt, and mixed uniformly to obtain an organic solvent mixture;

[0083] S4, 0.1 mol / L sodium gluconate was added to the organic solvent mixture and mixed uniformly, and the high-entropy electrolyte was obtained after filtration and impurity removal.

[0084] Example 8

[0085] S1, 1 mL of deionized water was taken as a base solution;

[0086] S2, 2 mol / L zinc perchlorate was added to the base solution to obtain an aqueous solution of zinc salt;

[0087] S3, 0.5% vol pyridine, 0.5% vol diethylene triamine and 3% vol butanediol were added to the aqueous solution of zinc salt, and mixed uniformly to obtain an organic solvent mixture;

[0088] S4, 0.2 mol / L sodium carboxymethyl cellulose was added to the organic solvent mixture and mixed uniformly, and the high-entropy electrolyte was obtained after filtration and impurity removal.

[0089] Example 9

[0090] S1, 1 mL of deionized water was taken as a base solution;

[0091] S2, 2 mol / L zinc perchlorate was added to the base solution to obtain an aqueous solution of zinc salt;

[0092] S3, 1% vol diethylene triamine, 2% vol N,N-dimethylacetamide and 5% vol ethylene glycol were added to the aqueous solution of zinc salt, and mixed uniformly to obtain an organic solvent mixture;

[0093] S4, 0.1 mol / L methylene bis naphthalene sulfonic acid sodium and 0.1 mol / L sodium gluconate were added into the organic solvent mixture and uniformly mixed, and then filtered and impurities were removed to obtain the high-entropy electrolyte.

[0094] Example 10

[0095] S1, 1 mL of deionized water was taken as a base solution;

[0096] S2, 2 mol / L zinc chloride was added into the base solution to obtain an aqueous solution of zinc salt;

[0097] S3, 1%vol diethylene triamine, 1%vol N,N-dimethylacetamide and 1%vol butanediol were added into the aqueous solution of zinc salt and uniformly mixed to obtain an organic solvent mixture;

[0098] S4, 0.2 mol / L sodium citrate was added into the organic solvent mixture and uniformly mixed, and then filtered and impurities were removed to obtain the high-entropy electrolyte.

[0099] Comparative Example 1

[0100] S1, 1 mL of deionized water was taken as a base solution;

[0101] S2, 1 mol / L zinc triflate was added into the base solution to obtain an aqueous solution of zinc salt as an electrolyte.

[0102] Comparative Example 2

[0103] The present comparative example is basically the same as Example 3, except that sodium hydroxypropyl cellulose and 3%vol acetonitrile (ACN) were not added.

[0104] Comparative Example 3

[0105] Zinc sulfate and water were mixed according to the ratio and uniformly, and then ethylene glycol, ethyl acetate and dimethyl sulfoxide were sequentially added, wherein the additive was a mixed solvent of ethyl acetate, ethylene glycol and dimethyl sulfoxide in a volume ratio of 1:1:1; the concentration of zinc sulfate was 1 mol / L; and the volume of the additive accounted for 15% of the total volume of the aqueous zinc ion battery electrolyte.

[0106] Comparative Example 4

[0107] Cyclohexanehexanol (0.0721 g, 4×10 -3 mol) was added into 20 mL of zinc sulfate aqueous solution with a concentration of 2 mol / L, and ultrasonic stirring was performed to fully dissolve it, to obtain a mixed solution with a cyclohexanehexanol concentration of 0.02 mol / L, i.e. an aqueous zinc ion battery electrolyte containing cyclohexanehexanol.

[0108] Comparative Example 5

[0109] The present control example is basically the same as example 3, except that 0.1 mol / L sodium hydroxypropyl cellulose and 0.1 mol / L sodium gluconate are not added.

[0110] Test example

[0111] Battery assembly:

[0112] Zinc metal is used as the negative electrode, MnO2 is used as the positive electrode, and a commercial polypropylene film is used as the separator; the high-entropy electrolyte solution prepared above is injected into the separator between the negative electrode and the positive electrode to ensure that the electrolyte is fully infiltrated.

[0113] Performance test:

[0114] The electrochemical performance of the zinc ion battery is tested at a low temperature of -25 DEG C, including conductivity, cycle life, and SEM indicators; through electrochemical test methods such as LSV and alternating current impedance, the performance of the high-entropy electrolyte solution under low temperature conditions is evaluated.

[0115] From Figures 1-2 It can be seen that the high-entropy electrolyte of the present application effectively reduces the freezing point by increasing the mixing entropy, avoiding the problem of ice formation of the traditional electrolyte in a low temperature environment.

[0116] Figure 3 The long-term cycle stability of the Zn metal anode in the electrolyte of the present application in examples 1-3 and control example 1 is shown in the figure, and it can be seen from the figure that the Zn metal anode in the electrolyte of the present application in example 3 has excellent cycle stability.

[0117] Figure 4 The discharge curves of the Zn||MnO2 button cell cycled at different current densities at -25 DEG C in the electrolyte of the present application in example 3 and control example 1 are shown in the figure, and it can be seen from the figure that the high-entropy electrolyte of the present application exhibits excellent low-temperature electrochemical performance compared with the traditional electrolyte.

[0118] Figures 5-8 The long-term cycle stability of the Zn metal anode in the electrolyte of the present application in control example 2, control example 3, example 4 and example 5 is shown in the figure, and it can be seen from the figure that the examples 4-5 of the present application have more excellent long-term cycle stability than the control examples 2-3.

[0119] Figure 9 The scanning electron microscope comparison figure of the zinc negative electrode surface after cycling of the aqueous zinc ion symmetrical button cell assembled in the control example 5 (left) and the example 5 (right) of the present application is shown in the figure, and it can be seen from the figure that the high-entropy electrolyte of the present application effectively improves the anti-freezing performance of the electrolyte at low temperature, promotes the uniform deposition and dissolution of zinc ions on the zinc negative electrode surface, and effectively inhibits the formation and excessive growth of zinc dendrites.

[0120] Figure 10The LSV graphs of the electrolyte in the present application comparative example 5 and example 5 can be seen from the figure that example 5 widens the electrochemical window and can inhibit hydrogen evolution.

[0121] Figure 11 The LSV graphs of the electrolyte in the present application comparative example 3, example 1, example 2 and example 3 can be seen from the figure that examples 1-3 of the present application widen the electrochemical window and can inhibit hydrogen evolution.

[0122] Figure 12 The electrochemical impedance graphs of the electrolyte in the present application comparative example 3, example 1, example 2 and example 3.

[0123] Table 1 is the cycle life of the aqueous zinc ion symmetrical button cell of the electrolyte containing different electrolytes.

[0124] Table 1

[0125]

[0126] In combination Figures 1-12 As can be seen from the data in table 1, the high-entropy electrolyte provided by examples 1-10 of the present application has the stability of long cycle at low temperature compared with comparative examples 1-5. Therefore, the high-entropy electrolyte of the present application effectively solves the problem of poor performance of the prior art aqueous zinc ion battery at low temperature, and significantly improves the low-temperature adaptability and service life of the battery.

[0127] In summary, the high-entropy electrolyte of the present application can reduce the freezing point by increasing the mixing entropy, so that the zinc ion battery still has high conductivity and stable electrochemical performance under extreme low temperature conditions (such as-25℃), avoiding the problem of freezing of the traditional electrolyte in low temperature environment; secondly, the high-entropy organic solvent can form a stable solvation shell with zinc ions, significantly reducing the interfacial resistance, improving the ion transmission speed, enhancing the kinetic characteristics of the battery, and prolonging the cycle life of the battery; at the same time, the high-entropy electrolyte of the present application effectively inhibits the growth of zinc dendrites through optimization of the composition, reduces the risk of dendrite puncturing the separator, and improves the safety and service life of the battery. Therefore, compared with the traditional electrolyte, the high-entropy electrolyte of the present application has multi-dimensional adjustment ability in the aspects of freezing point adjustment, electrochemical stability and interface structure optimization, and significantly improves the low-temperature adaptability and service life of the battery.

[0128] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or replace some or all of the technical features thereof with equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high entropy electrolyte, characterized in that Including deionized water, organic solvents, zinc salts and additives, Wherein, the organic solvent is acetonitrile, diethylenetriamine, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol and glycerol, and the volume fraction of the organic solvent is 0.1%-10%; The additives are sodium citrate and sodium hydroxypropyl cellulose. In the high entropy electrolyte, the concentration of sodium salt is 0.1-2 mol / L, and the concentration of the additives is 0.1-2 mol / L. The zinc salt is zinc sulfate and zinc trifluoromethanesulfonate, and the concentration of the zinc salt is 1-5 mol / L; The pH value of the high entropy electrolyte is 5-8.

2. The method for preparing the high entropy electrolyte according to claim 1, characterized in that: The following steps are involved: S1. Take a certain amount of deionized water as the base solution; S2. adding zinc salt to the base solution to obtain an aqueous solution of zinc salt; S3, adding one or more organic solvents to the aqueous solution of the zinc salt and mixing them uniformly to obtain a high entropy organic solvent mixture; S4. Add additives to the high-entropy organic solvent mixture and mix well to obtain a high-entropy electrolyte.

3. The preparation method according to claim 2, characterized in that Also includes: The uniformly mixed high entropy electrolyte is filtered and impurities are removed.

4. Use of the high entropy electrolyte according to claim 1 in an aqueous zinc ion battery or a zinc ion electrochemical energy storage device.

5. An aqueous zinc ion battery, characterized in that The aqueous zinc ion battery comprises a positive electrode, a negative electrode, a separator and the high entropy electrolyte according to claim 1.

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