Aqueous electrolyte composition, aqueous electrolyte and zinc ion secondary battery

Abstract

To provide an aqueous electrolyte composition for use in a zinc ion secondary battery having superior performance.SOLUTION: An aqueous electrolyte composition includes water and a salt-based composition including zinc chloride and manganese(II) acetate, and the amount of zinc chloride in the salt-based composition ranges from 10 mol to 30 mol for every kilogram of water used.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the field of secondary batteries, and particularly to an aqueous electrolyte composition, an aqueous electrolyte using the aqueous electrolyte composition, and a zinc ion secondary battery including the aqueous electrolyte.

Background Art

[0002] Aqueous zinc ion secondary batteries have the advantages of high energy density, high safety, and low manufacturing cost. However, during the charge-discharge cycle of an aqueous zinc ion secondary battery, zinc dendrites generated and accumulated on the surface of the negative electrode pierce through the separator to short-circuit the battery, and manganese irreversibly dissolves from the manganese-based positive electrode into the aqueous electrolyte, causing the collapse of the manganese-based positive electrode. As a result, the overall efficiency of the aqueous zinc ion secondary battery declines and the operating life is reduced.

[0003] Current methods for solving the above problems include, for example, performing surface treatment on the negative electrode, performing surface treatment on the manganese-based positive electrode, and adding an organic compound to the electrolyte to protect the negative electrode. However, performing surface treatment on the negative electrode and the manganese-based positive electrode has the problem of complex processes, and adding an organic compound to the electrolyte has an adverse effect on the performance of the aqueous zinc ion secondary battery.

[0004] Also, for example, Patent Document 1 discloses an electrolyte for a zinc-ion battery, and the electrolyte for the zinc-ion battery includes a zinc electrolyte and a manganese salt-containing additive. The zinc electrolyte is selected from at least one of zinc sulfate (ZnSO4), zinc chloride (ZnCl2), zinc nitrate (Zn(NO3)2), zinc chlorate, zinc perchlorate, zinc acetate (Zn(O2CCH3)2), zinc bromide (ZnBr2), zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonyl)imide zinc, and zinc hydroxide, and the concentration of the zinc electrolyte can be 0.5 M to 3 M.

[0005] The manganese salt is selected from at least one of manganese sulfate (MnSO4), manganese carbonate (MnCO3), manganese monoxide (MnO), manganese(II) chloride (MnCl2), manganese nitrate (Mn(NO3)2), and manganese(II) acetate (Mn(CH3COO)2), and the concentration of the manganese salt can be 0.01 M to 0.5 M. The electrolyte for the zinc-ion battery can prevent manganese from dissolving in the zinc electrolyte and improve the stability of the structure of the positive electrode.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide an aqueous electrolyte composition and an aqueous electrolyte that solve irreversible dissolution of zinc dendrites and manganese in an aqueous electrolyte with a new mechanism, and a zinc ion secondary battery using the aqueous electrolyte.

Means for Solving the Problems

[0008] To achieve the above object, the present invention includes water and a salt-based composition containing zinc chloride and manganese(II) acetate, and provides an aqueous electrolyte composition characterized in that, for every 1 kilogram (kg) of the amount of water used, the amount of zinc chloride used in the salt-based composition ranges from 10 mol to 30 mol.

[0009] Further, the present invention includes water and a salt-based composition containing zinc chloride, a manganese(II) salt, and an acetate, and the acetate is at least one selected from the group consisting of sodium acetate, potassium acetate, lithium acetate, magnesium acetate, and calcium acetate, the manganese(II) salt is at least one selected from the group consisting of manganese(II) chloride, manganese nitrate, manganese sulfate, manganese(II) perchlorate (Mn(ClO4)2), and manganese(II) bis(trifluoromethanesulfonyl)imide (Mn(TFSI)2), provides an aqueous electrolyte composition characterized in that, for every 1 kilogram of the amount of water used, the amount of zinc chloride used in the salt-based composition ranges from 10 mol to 30 mol.

[0010] Further, the present invention is a solvated product of the above aqueous electrolyte composition, [Zn(H2O)6] 2+ ion clusters, and [ZnCl 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and [Mn(CH3COO) 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and provides an aqueous electrolyte characterized by including these.

[0011] Further, the present invention provides a zinc ion secondary battery characterized by including a manganese-based positive electrode, a negative electrode installed at a distance from the manganese-based positive electrode, and the above aqueous electrolyte in contact with the manganese-based positive electrode and the negative electrode.

Advantages of the Invention

[0012] According to the present invention, due to the salt composition of the aqueous electrolyte composition and the range of the amount of zinc chloride used, the above ion clusters exist in the aqueous electrolyte formed by the aqueous electrolyte composition. In particular, [ZnCl 2+x (H2O) n x- ion clusters and [Mn(CH3COO) 2+x (H2O) n x- ion clusters exist, so the zinc ion secondary battery has good cycle performance, a higher discharge specific capacity, and a higher coulombic efficiency.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Mode for Carrying Out the Invention

[0014] To more clearly explain the objectives, technical means, and advantages of the embodiments of the present invention, hereinafter, in combination with the accompanying drawings of the embodiments of the present invention, the technical means in the embodiments of the present invention will be clearly and completely described. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention depicted and shown in the accompanying drawings can be arranged and designed in various different configurations. Accordingly, hereinafter, the detailed description of the embodiments of the present invention provided in the accompanying drawings does not constitute any limitation to the protection scope of the present invention, but merely shows the selected embodiments of the present invention.

[0015] Also, in the description of the present invention, terms such as "first", "second", etc. are used solely for the purpose of distinction and do not teach or imply relative importance.

[0016] In the first embodiment of the present invention, the aqueous electrolyte composition of the present invention comprises water and a salt-based composition containing zinc chloride and manganese(II) acetate.

[0017] For every 1 kilogram of the amount of water used, the range of the amount of zinc chloride used in the salt-based composition is 10 mol to 30 mol.

[0018] In some embodiments, for every 1 kilogram of the amount of water used, the range of the amount of zinc chloride used in the salt-based composition is 19 mol to 30 mol.

[0019] In some specific examples, the amount of zinc chloride used is 19 mol for every 1 kilogram of the amount of water used.

[0020] For every 1 kilogram of the amount of water used, the range of the amount of manganese(II) acetate used in the salt-based composition is 0.5 mol to 5 mol.

[0021] In some embodiments, for every 1 kilogram of the amount of water used, the range of the amount of manganese(II) acetate used in the salt-based composition is 1 mol to 3 mol.

[0022] In some embodiments, the amount of manganese(II) acetate used in the salt-based composition ranges from 1 mol to 2 mol per 1 kilogram of water used.

[0023] In some specific examples, the amount of manganese(II) acetate used ranges from 1 mol to 5 mol per 1 kilogram of water used.

[0024] The aqueous electrolyte of the present invention comprising the above aqueous electrolyte composition contains CH3COO - ions, [Zn(H2O)6] 2+ ion clusters, [ZnCl 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and [Mn(CH3COO) 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4.

[0025] The range of the molality of zinc chloride in the aqueous electrolyte is from 10 mol / kg to 30 mol / kg, in some embodiments from 19 mol / kg to 30 mol / kg, and as a specific example, it is 19 mol / kg.

[0026] The range of the molality of manganese(II) acetate in the aqueous electrolyte is from 0.5 mol / kg to 5 mol / kg, in some embodiments from 1 mol / kg to 3 mol / kg, in some embodiments from 1 mol / kg to 2 mol / kg, and as a specific example, it is from 1 mol / kg to 5 mol / kg.

[0027] ​​More specifically, the aqueous electrolyte of this embodiment is formed by solvation of water and a salt-based composition containing zinc chloride and manganese(II) acetate. Since the amount of zinc chloride used is as large as 10 mol to 30 mol per 1 kg of water used, after zinc chloride and manganese(II) acetate are dissolved in water, they are solvated with water to promote the formation of new covalent bonds. Moreover, since most water molecules are solvated with zinc chloride and manganese(II) acetate, most of the aqueous electrolyte of this embodiment is the above ion cluster and there are few free water molecules.

[0028] In the aqueous electrolyte of this embodiment, the CH3COO - ions are derived from manganese(II) acetate and do not participate in coordination. [Mn(CH3COO) 2+x (H2O) n x- The ion cluster is formed by coordination of the CH3COO - ions of manganese(II) acetate and Mn 2+ ions with water molecules. [ZnCl 2+x (H2O) n x- The ion cluster is formed by coordination of zinc chloride with water molecules. [Zn(H2O)6] 2+ The ion cluster is formed by coordination of the Zn 2+ ions of zinc chloride with water molecules.

[0029] In the second embodiment of the present invention, the aqueous electrolyte composition of the present invention contains water and a salt-based composition. The salt-based composition contains zinc chloride, a manganese(II) salt, and an acetate.

[0030] The acetate is at least one selected from the group consisting of sodium acetate, potassium acetate, lithium acetate, magnesium acetate, and calcium acetate.

[0031] ​​The manganese (II) salt is at least one selected from the group consisting of manganese (II) chloride, manganese nitrate, manganese sulfate, manganese (II) perchlorate, and manganese (II) bis(trifluoromethanesulfonyl)imide.

[0032] For every 1 kilogram of the amount of water used, the range of the amount of zinc chloride used in the salt-based composition is 10 mol to 30 mol.

[0033] In some embodiments, for every 1 kilogram of the amount of water used, the range of the amount of zinc chloride used in the salt-based composition is 19 mol to 30 mol.

[0034] In some specific examples, the amount of zinc chloride used is 19 mol for every 1 kilogram of the amount of water used.

[0035] For every 1 kilogram of the amount of water used, the range of the amount of acetate used in the salt-based composition is 1 mol to 10 mol.

[0036] In some embodiments, for every 1 kilogram of the amount of water used, the range of the amount of acetate used in the salt-based composition is 2 mol to 4 mol.

[0037] In some specific examples, the range of the amount of acetate used is 2 mol to 4 mol for every 1 kilogram of the amount of water used.

[0038] For every 1 kilogram of the amount of water used, the range of the amount of manganese (II) salt used in the salt-based composition is 0.5 mol to 5 mol.

[0039] In some embodiments, for every 1 kilogram of the amount of water used, the range of the amount of manganese (II) salt used in the salt-based composition is 0.5 mol to 1 mol.

[0040] In some specific examples, the range of the amount of manganese (II) salt used is 0.5 mol to 1 mol for every 1 kilogram of the amount of water used.

[0041] The aqueous electrolyte composed of the aqueous electrolyte composition of this second embodiment also contains CH3COO - ions, [Zn(H2O)6] 2+ ion clusters, [ZnCl 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and [Mn(CH3COO) 2+x (H2O) n x- ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4.

[0042] The range of the weight molar concentration of zinc chloride in the aqueous electrolyte is 10 mol / kg to 30 mol / kg, in some embodiments 19 mol / kg to 30 mol / kg, and as a specific example 19 mol / kg.

[0043] The range of the weight molar concentration of acetate in the aqueous electrolyte is 1 mol / kg to 10 mol / kg, in some embodiments 2 mol / kg to 4 mol / kg, and as a specific example 2 mol / kg to 4 mol / kg.

[0044] The range of the weight molar concentration of manganese(II) salt in the aqueous electrolyte is 0.5 mol / kg to 5 mol / kg, in some embodiments 0.5 mol / kg to 1 mol / kg, and as a specific example 0.5 mol / kg to 1 mol / kg.

[0045] More specifically, the aqueous electrolyte of this embodiment is formed by the solvation of water and a salt-based composition containing zinc chloride, manganese(II) salt, and acetate. Since the amount of zinc chloride used is as high as 10 mol to 30 mol per 1 kilogram of water used, after zinc chloride, manganese(II) salt, and acetate are dissolved in water, they solvate with water to promote the formation of new coordination bonds. And since most water molecules solvate with zinc chloride, manganese(II) salt, and acetate, most of the aqueous electrolyte of this embodiment is the above ion clusters and there are few free water molecules.​​

[0046] In the aqueous electrolyte of this embodiment, CH3COO - ions are derived from acetate and do not participate in coordination. [Mn(CH3COO) 2+x (H2O) n x- The ion cluster is formed by the coordination of CH3COO - ions of acetate and Mn 2+ ions of manganese (II) salt with water molecules. [ZnCl 2+x (H2O) n x- The ion cluster is formed by the coordination of zinc chloride with water molecules. [Zn(H2O)6] 2+ The ion cluster is formed by the coordination of Zn 2+ ions of zinc chloride with water molecules.

[0047] The zinc ion secondary battery of the present invention includes a manganese-based positive electrode, a negative electrode installed at a distance from the manganese-based positive electrode, a separator installed between the manganese-based positive electrode and the negative electrode, and the aqueous electrolyte of the present invention in contact with the manganese-based positive electrode and the negative electrode.

[0048] The manganese-based positive electrode includes a current collector and an active layer provided on the surface of the current collector.

[0049] The active layer is formed by drying a paste containing manganese dioxide powder, conductive powder, and a binder.

[0050] Examples of the current collector include, but are not limited to, carbon fiber paper, carbon felt, titanium foil, or tungsten foil.

[0051] ​​The crystal structure of the manganese dioxide powder includes, for example, α-MnO2, β-MnO2, δ-MnO2, γ-MnO2, λ-MnO2, or R-MnO2, but is not limited thereto.

[0052] The conductive powder includes, for example, Super-P carbon black, acetylene black, or Ketjen black, but is not limited thereto.

[0053] The binder includes, for example, a polyvinylidene difluoride-based binder, a polytetrafluoroethylene-based binder, or carboxymethyl cellulose, but is not limited thereto.

[0054] The negative electrode includes a metal sheet, and the metal sheet includes, for example, a zinc metal sheet, a copper metal sheet, a lead metal sheet, a tungsten (W) metal sheet, or an indium (In) metal sheet, but is not limited thereto.

[0055] The separator includes, for example, a glass fiber separator, but is not limited thereto.

[0056] Hereinafter, the electrochemical reaction when the zinc ion secondary battery of the present invention is charged or discharged will be described.

[0057] When the zinc ion secondary battery is charged, an oxidation reaction occurs at the manganese-based positive electrode. At the start of charging, Zn 2+ ions deintercalate from the structure of the manganese-based positive electrode (Equation 1). When the zinc ion secondary battery is charged until it reaches a high voltage (about 1.8V), Mn(CH3COO) 2+x (H2O) n x- The reaction in which the ion cluster loses the solvation shell on the surface of the manganese-based positive electrode occurs, and Mn 2+ ​Ions, H2O molecules, and CH3COO - Ions are released (in Equation 2, where x is 0 and n is 4 in Mn(CH3COO) 2+x (H2O) n ) x- Taking ion clusters as an example). And Mn 2+ Ions react with H2O molecules to form MnO2 solids, which deposit on the surface of the manganese-based cathode (Equation 3).

[0058] When the zinc-ion secondary battery discharges, a reduction reaction occurs at the manganese-based cathode, and the MnO2 solid dissolves into Mn 2+ Ions and return to the aqueous electrolyte (Equation 4), and Zn 2+ Ions intercalate into the structure of the manganese-based cathode (Equation 5).

[0059] JPEG2025091324000002.jpg40170

[0060] In the present invention, due to the components of the salt-based composition of the aqueous electrolyte composition and the range of the usage amount of zinc chloride, [Zn(H2O)6] is present in the aqueous electrolyte composed of the aqueous electrolyte composition 2+ Ion clusters, [ZnCl 2+x (H2O) n ) x- Ion clusters, and [Mn(CH3COO) 2+x (H2O) n ) x- Ion clusters exist, and most of the aqueous electrolyte is the above ion clusters, with few free water molecules. And [ZnCl 2+x (H2O) n ) x- Ion clusters are dominant in quantity over [Zn(H2O)6] 2+ Ion clusters. Since there are few free water molecules in the aqueous electrolyte, the OH - Generated by the electrolysis of free water molecules on the surface of the negative electrode decreases, and the irreversible reaction Zn 2+ +2OH - → Zn(OH)2 occurring on the surface of the negative electrode decreases, and the Zn(OH)2 is a common type of zinc dendrite.

[0061] Also, [ZnCl 2+x (H2O) n x- The Zn in the solvation shell structure of the ion cluster 2+ ion forms a coordination bond with the Cl - ion, so [ZnCl 2+x (H2O) n x- There are fewer water molecules in the ion cluster, and thus [ZnCl 2+x (H2O) n x- The ion cluster is beneficial by reducing the formation of zinc dendrites.

[0062] In particular, [Mn(CH3COO) 2+x (H2O) n x- Due to the presence of the ion cluster, a new electrochemical reaction mechanism is imparted to the manganese-based positive electrode, so that not only is the redox activity of the zinc-ion secondary battery not suppressed by the Cl - ion, but furthermore, the irreversible dissolution of the manganese-based positive electrode is reduced, and thus the manganese-based positive electrode has better performance.

[0063] The [ZnCl 2+x (H2O) n x- ion cluster in the aqueous electrolyte effectively reduces the formation of zinc dendrites, and the [Mn(CH3COO) 2+x (H2O) n x- ion cluster effectively improves the performance of the manganese-based positive electrode and has an overall effect, thus providing a stable electrochemical environment for the zinc-ion secondary battery, and as a result, the zinc-ion secondary battery of the present invention has excellent performance and cycle life.

[0064] Hereinafter, embodiments of the present invention will be described. It should be understood that these embodiments are illustrative and explanatory and should not be construed as limiting the present invention.

Embodiment

[0065] [Example 1] According to the types and usage amounts of the salt-based compositions shown in Table 1, zinc chloride and manganese(II) acetate with the usage amounts were dissolved in 1 kilogram of ultrapure water at room temperature (25°C), and solvation occurred to prepare an aqueous electrolyte solution with the concentrations shown in Table 2. In an environment of normal temperature and pressure, a manganese dioxide positive electrode, a glass fiber separator, a zinc negative electrode, and the aqueous electrolyte solution were assembled into a zinc-ion secondary battery in the form of a pouch cell. The manganese dioxide positive electrode was prepared by uniformly mixing manganese dioxide powder with a crystal structure of β-MnO2, Super-P carbon black (manufacturer: MTI Corporation, model number: Lib-SP), and a polyvinylidene fluoride-based binder (manufacturer: MTI Corporation, model number: Lib-PVDF) in a usage amount such that the weight ratio of manganese dioxide powder:Super-P carbon black:polyvinylidene fluoride-based binder was 8:1:1 to form a paste, and then applying the paste to a titanium foil serving as a current collector and drying it. The zinc negative electrode is a sheet of metallic zinc.

[0066] [Examples 2 to 5] The differences between Examples 2 to 5 and Example 1 are the usage amount of manganese(II) acetate. The usage amounts of manganese(II) acetate in Examples 2 to 5 are shown in Table 1, and the concentrations of the obtained aqueous electrolyte solutions are shown in Table 2.

[0067] [Example 6] The difference between Example 6 and Example 1 is that manganese(II) chloride and sodium acetate are used instead of manganese(II) acetate. The usage amounts of manganese(II) chloride and sodium acetate in Example 6 are shown in Table 1, and the concentration of the obtained aqueous electrolyte solution is shown in Table 2.

[0068] [Examples 7 to 9] The differences between Examples 7 to 9 and Example 6 lie in the usage amounts of manganese(II) chloride and sodium acetate. The usage amounts of manganese(II) chloride and sodium acetate in Examples 7 to 9 are shown in Table 1, and the concentrations of the obtained aqueous electrolytes are shown in Table 2.

[0069] [Comparative Examples 1 to 16] In Comparative Example 1 and Comparative Example 10, only zinc chloride was dissolved in ultrapure water to prepare an aqueous electrolyte, and the usage amounts of zinc chloride and ultrapure water are shown in Table 1.

[0070] In Comparative Examples 2 to 6 and Comparative Examples 14 to 16, zinc chloride and manganese(II) chloride were dissolved in ultrapure water to prepare an aqueous electrolyte, and the usage amounts of zinc chloride, manganese(II) chloride, and ultrapure water are shown in Table 1.

[0071] In Comparative Examples 7 to 9, zinc chloride and sodium acetate were dissolved in ultrapure water to prepare an aqueous electrolyte, and the usage amounts of zinc chloride, sodium acetate, and ultrapure water are shown in Table 1.

[0072] In Comparative Examples 11 to 13, zinc chloride and manganese(II) acetate were dissolved in ultrapure water to prepare an aqueous electrolyte, and the usage amounts of zinc chloride, manganese(II) acetate, and ultrapure water are shown in Table 1. The concentrations of the aqueous electrolytes obtained in Comparative Examples 1 to 16 are shown in Table 2.

[0073] Also, in Comparative Examples 1 to 16, zinc-ion secondary batteries were manufactured by the same manufacturing method as in Example 1 using the aqueous electrolytes obtained in the respective comparative examples. Analysis by Raman Spectroscopy:

[0074] Using a micro Raman spectrometer (manufacturer: ProTrusTech, model number: RAMaker), the aqueous electrolytes obtained in Examples 1 to 5, Examples 8 to 9, and Comparative Examples 1 to 16 were analyzed, and the figures of the obtained Raman spectra are shown in FIGS. 1 to 5.

[0075] Referring to the literature of Raman spectroscopy, at a Raman shift in the range of 175 cm -1 ~1200 cm -1 there is a characteristic peak at 300 cm -1 corresponding to the presence of an ion cluster [ZnCl 2+x (H2O) n x- where the range of x is 0 to 3 and the range of n is 1 to 4, and there is a characteristic peak at 390 cm -1 corresponding to the presence of an ion cluster [Zn(H2O)6] 2+ and there are characteristic peaks at 500 cm -1 , 690 cm -1 and 960 cm -1 corresponding to the presence of CH3COO - ions, and there is a characteristic peak at 610 cm -1 corresponding to the presence of an ion cluster [Mn(CH3COO) 2+x (H2O) n x- where the range of x is 0 to 3 and the range of n is 1 to 4.

[0076] Performance test of zinc ion secondary battery: Using a battery charge-discharge tester (manufacturer: NEWARE, model number: CT-4008-5V20mA), at test conditions of an environmental temperature of 27 °C, a charge current density of 100 mA / g, a charge cutoff voltage of 1.9 V, a discharge current density of 100 mA / g, a discharge cutoff voltage of 0.8 V, and a cycle number of 250 times, charge-discharge cycles were performed on the zinc ion secondary batteries obtained in Examples 1 to 9 and Comparative Examples 1 to 16. The test results are shown in FIGS. 6 to 30 and Table 2. Among them, the Coulomb efficiency of the nth cycle (abbreviation: CE%) = discharge specific capacity of the nth cycle ÷ charge specific capacity of the nth cycle × 100%, and the average Coulomb efficiency is the average value of the Coulomb efficiencies from the 50th cycle to the 250th cycle.

[0077] Table 1 JPEG2025091324000003.jpg143170​​

[0078] Table 2 JPEG2025091324000004.jpg244170 JPEG2025091324000005.jpg156170

[0079] As shown in Fig. 1, in the Raman spectra of the aqueous electrolytes obtained in Examples 1 to 5, there are characteristic peaks of [ZnCl 2+x (H2O) n x- ion clusters and characteristic peaks of [Mn(CH3COO) 2+x (H2O) n x- ion clusters. As shown in Fig. 2, in the Raman spectra of the aqueous electrolytes obtained in Examples 8 and 9, there are characteristic peaks of [ZnCl 2+x (H2O) n x- ion clusters and characteristic peaks of [Mn(CH3COO) 2+x (H2O) n x- ion clusters.

[0080] As shown in Table 2 and Figs. 6 to 14, the zinc ion secondary batteries obtained in Examples 1 to 9 have high Coulomb efficiency, indicating that the overall efficiency of the zinc ion secondary batteries obtained in Examples 1 to 9 is excellent. The zinc ion secondary batteries obtained in Examples 1 to 9 have high discharge specific capacity, indicating that the energy storage capacity of the zinc ion secondary batteries obtained in Examples 1 to 9 is excellent. Moreover, since there is no obvious decline in the Coulomb efficiency of the zinc ion secondary batteries obtained in Examples 1 to 9 from the first cycle to the 250th cycle, it shows that the cycle life of the zinc ion secondary batteries obtained in Examples 1 to 9 is long.

[0081] As shown in Fig. 3, in the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 1 to 6, there are [Mn(CH3COO) 2+x (H2O) n x- ​​​​​There is no characteristic peak of the ion cluster. As shown in FIG. 4, in the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 7 to 9, [Mn(CH3COO) 2+x (H2O) n x- There is no characteristic peak of the ion cluster. As shown in FIG. 5, in the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 10 to 16, [Mn(CH3COO) 2+x (H2O) n x- There is no characteristic peak of the ion cluster, and for [ZnCl 2+x (H2O) n x- there is a characteristic peak of the ion cluster, but the intensity is weak.

[0082] Also, as shown in Table 2 and FIGS. 15 to 30, the zinc ion secondary batteries obtained in Comparative Examples 1 to 9 have a low discharge specific capacity, the zinc ion secondary battery obtained in Comparative Example 10 has a reduced Coulomb efficiency, and the zinc ion secondary batteries obtained in Comparative Examples 11 to 16 have a low Coulomb efficiency and a large decay width from the first cycle to the 250th cycle.

[0083] Therefore, when comparing the performance of the zinc ion secondary battery obtained in the example with that obtained in the comparative example, it is proved that the [Mn(CH3COO) 2+x (H2O) n x- ion cluster present in the aqueous electrolyte of the present invention can endow the zinc ion secondary battery with better discharge specific capacity, Coulomb efficiency and cycle life.

[0084] According to the above content, the aqueous electrolyte using the aqueous electrolyte composition of the present invention can endow the zinc ion secondary battery with a higher discharge specific capacity, a higher average Coulomb efficiency and a longer cycle life.

[0085] ​​​​Although the present invention has been described in connection with what is considered to be exemplary embodiments, the present invention is not limited to the disclosed embodiments and is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to include all such modifications and equivalent arrangements.

[0086] The above embodiments are illustrative of the principles and effects of the present invention and do not limit the present invention. Those skilled in the art can make some changes and modifications to the above embodiments on the premise of not departing from the spirit and scope of the present invention. Therefore, all changes and modifications made on the premise that those skilled in the art do not depart from the gist of the present invention should also be included in the protection scope of the present invention.

Industrial Applicability

[0087] The aqueous electrolyte composition of the present invention and the aqueous electrolyte thereby are suitable for providing a zinc ion secondary battery having more excellent performance.

Claims

1. water, and a salt-based composition containing zinc chloride and manganese(II) acetate, wherein the amount of zinc chloride used in the salt-based composition ranges from 10 mol to 30 mol per 1 kilogram of the amount of water used, characterized in that it is an aqueous electrolyte composition.

2. The aqueous electrolyte composition according to claim 1, characterized in that the amount of zinc chloride used in the salt-based composition ranges from 19 mol to 30 mol per 1 kilogram of the amount of water used.

3. The aqueous electrolyte composition according to claim 1, characterized in that the amount of manganese(II) acetate used in the salt-based composition ranges from 0.5 mol to 5 mol per 1 kilogram of the amount of water used.

4. The aqueous electrolyte composition according to claim 3, characterized in that the amount of manganese(II) acetate used in the salt-based composition ranges from 1 mol to 5 mol per 1 kilogram of the amount of water used.

5. The aqueous electrolyte composition according to claim 3, characterized in that the amount of manganese(II) acetate used in the salt-based composition ranges from 1 mol to 3 mol per 1 kilogram of the amount of water used.

6. water, and a salt-based composition containing zinc chloride, manganese(II) salt and acetate, wherein the acetate is at least one selected from the group consisting of sodium acetate, potassium acetate, lithium acetate, magnesium acetate and calcium acetate, the manganese(II) salt is at least one selected from the group consisting of manganese(II) chloride, manganese nitrate, manganese sulfate, manganese(II) perchlorate and manganese(II) bis(trifluoromethanesulfonyl)imide, wherein the amount of zinc chloride used in the salt-based composition ranges from 10 mol to 30 mol per 1 kilogram of the amount of water used, characterized in that it is an aqueous electrolyte composition.

7. For every 1 kilogram of water usage, the range of the usage amount of zinc chloride in the salt-based composition is 19 mol to 30 mol, and the aqueous electrolyte composition according to claim 6 is characterized by this.

8. For every 1 kilogram of water usage, the range of the usage amount of acetate in the salt-based composition is 1 mol to 10 mol, and the aqueous electrolyte composition according to claim 6 is characterized by this.

9. For every 1 kilogram of water usage, the range of the usage amount of acetate in the salt-based composition is 2 mol to 4 mol, and the aqueous electrolyte composition according to claim 8 is characterized by this.

10. For every 1 kilogram of water usage, the range of the usage amount of manganese (II) salt in the salt-based composition is 0.5 mol to 5 mol, and the aqueous electrolyte composition according to claim 6 is characterized by this.

11. For every 1 kilogram of water usage, the range of the usage amount of manganese (II) salt in the salt-based composition is 0.5 mol to 1 mol, and the aqueous electrolyte composition according to claim 10 is characterized by this.

12. The aqueous electrolyte composition according to any one of claims 1 to 11 is solvated, [Zn(H ２ O) ６ < ２＋ ion clusters, and [ZnCl ２＋ｘ (H ２ O) ｎ < ｘ－ ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and [Mn(CH ３ COO) ２＋ｘ (H ２ O) ｎ < ｘ－ ion clusters where the range of x is 0 to 3 and the range of n is 1 to 4, and it is characterized by including these, an aqueous electrolyte.

13. A zinc ion secondary battery comprising a manganese-based positive electrode, a negative electrode disposed at a distance from the manganese-based positive electrode, and the aqueous electrolyte according to claim 12 in contact with the manganese-based positive electrode and the negative electrode.

Images