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 more particularly to aqueous electrolyte compositions, aqueous electrolytes obtained from the aqueous electrolyte composition, and zinc-ion secondary batteries containing the aqueous electrolyte. [Background technology]

[0002] Water-based zinc-ion secondary batteries have advantages such as high energy density, high safety, and low manufacturing costs. However, during the charge-discharge cycle, zinc dendrites that form and accumulate on the surface of the negative electrode can penetrate the separator and short-circuit the battery, and manganese irreversibly dissolves from the manganese-based positive electrode into the water-based electrolyte, causing the manganese-based positive electrode to disintegrate. These factors lead to a decline in the overall efficiency of the water-based zinc-ion secondary battery and a reduction in its operating life.

[0003] Current methods to solve the above problems include, for example, surface treatment of the negative electrode and the manganese-based positive electrode, or adding organic compounds to the electrolyte to protect the negative electrode. However, surface treatment of the negative electrode and the manganese-based positive electrode has the problem of being a complex process, and adding organic compounds to the electrolyte has an adverse effect on the performance of aqueous zinc-ion secondary batteries.

[0004] Furthermore, for example, Patent Document 1 discloses an electrolyte for a zinc-ion battery, which includes a zinc electrolyte and a manganese salt-containing additive. The zinc electrolyte is selected from the group consisting 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 0.5M to 3M.

[0005] The manganese salt is selected from the group consisting 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 may be 0.01M to 0.5M. This electrolyte for zinc-ion batteries prevents manganese from dissolving in the zinc electrolyte, thereby improving the structural stability of the positive electrode. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2023 / 140569 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide an aqueous electrolyte composition and aqueous electrolyte that solve the irreversible dissolution of zinc dendrites and manganese in aqueous electrolytes by a novel mechanism, and a zinc-ion secondary battery that uses the aqueous electrolyte. [Means for solving the problem]

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

[0009] Furthermore, the present invention relates to water and A salt system composition containing zinc chloride, manganese(II) salt, and acetate, The acetate is selected from the group consisting of sodium acetate, potassium acetate, lithium acetate, magnesium acetate, and calcium acetate, with at least one selected from this group. The manganese(II) salt is selected from the group consisting of manganese(II) chloride, manganese nitrate, manganese sulfate, manganese(II) perchlorate (Mn(ClO4)2), and bis(trifluoromethanesulfonyl)imide manganese(II) (Mn(TFSI)2). The present invention provides an aqueous electrolyte composition characterized in that, for every kilogram of water used, the amount of zinc chloride used in the salt system 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+ an ion cluster, and [ZnCl 2+x (H2O) n x- an ion cluster in which 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- an ion cluster in which the range of x is 0 to 3 and the range of n is 1 to 4, and provides an aqueous electrolyte characterized by containing the same.

[0011] Further, the present invention provides a zinc ion secondary battery comprising 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 are present in the aqueous electrolyte formed by the aqueous electrolyte composition. Particularly, [ZnCl 2+x (H2O) n x- ion clusters and [Mn(CH3COO) 2+x (H2O) n x- ion clusters are present, so that 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] ​​​​This figure shows the Raman spectra of the aqueous electrolytes of Examples 1 to 5 and Comparative Example 1 of the present invention within the Raman shift range of 175 cm⁻¹ to 1200 cm⁻¹. [Figure 2] This figure shows the Raman spectra of the aqueous electrolytes of Examples 8 to 9 and Comparative Example 1 of the present invention within the Raman shift range of 175 cm⁻¹ to 1200 cm⁻¹. [Figure 3] This figure shows the Raman spectra of the aqueous electrolytes of Comparative Examples 1 to 6 within the Raman shift range of 175 cm⁻¹ to 1200 cm⁻¹. [Figure 4] This figure shows the Raman spectra of the aqueous electrolytes of Comparative Examples 1 and 7 to 9 within the Raman shift range of 175 cm⁻¹ to 1200 cm⁻¹. [Figure 5] This figure shows the Raman spectra of the aqueous electrolytes of Comparative Examples 10 to 16 within the Raman shift range of 175 cm⁻¹ to 1200 cm⁻¹. [Figure 6] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 1 of the present invention. [Figure 7] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 2 of the present invention. [Figure 8] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 3 of the present invention. [Figure 9] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 4 of the present invention. [Figure 10] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 5 of the present invention. [Figure 11] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 6 of the present invention. [Figure 12] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 7 of the present invention. [Figure 13] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 8 of the present invention. [Figure 14] This is a data diagram showing the performance test results of the zinc-ion secondary battery according to Example 9 of the present invention. [Figure 15] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 1. [Figure 16] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 2. [Figure 17] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 3. [Figure 18] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 4. [Figure 19] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 5. [Figure 20] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 6. [Figure 21] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 7. [Figure 22] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 8. [Figure 23] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 9. [Figure 24] This is a data chart showing the performance test results of the zinc-ion secondary battery in Comparative Example 10. [Figure 25] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 11. [Figure 26] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 12. [Figure 27] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 13. [Figure 28] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 14. [Figure 29] This is a data chart showing the performance test results of the zinc-ion secondary battery in Comparative Example 15. [Figure 30] This is a data chart showing the performance test results for the zinc-ion secondary battery in Comparative Example 16. [Modes for carrying out the invention]

[0014] To more clearly illustrate the object, technical means, and advantages of the embodiments of the present invention, the technical means in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. It will be clear that the embodiments described are some, and not all, embodiments of the present invention. Typically, the components of the embodiments of the present invention depicted and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the detailed description of the embodiments of the present invention provided below in the accompanying drawings does not constitute any limitation on the scope of protection of the present invention, but merely illustrates selected embodiments of the present invention.

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

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

[0017] For every kilogram of water used, the amount of zinc chloride used in the aforementioned salt system composition ranges from 10 mol to 30 mol.

[0018] In some embodiments, the range of zinc chloride used in the salt system composition is 19 mol to 30 mol per kilogram of water used.

[0019] In some specific examples, the amount of zinc chloride used is 19 moles per kilogram of water used.

[0020] For every kilogram of water used, the amount of manganese(II) acetate used in the aforementioned salt system composition ranges from 0.5 mol to 5 mol.

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

[0022] In some embodiments, the amount of manganese(II) acetate used in the salt system composition is in the range of 1 mol to 2 mol per kilogram of water used.

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

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

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

[0026] The molar concentration of manganese(II) acetate in the aqueous electrolyte is in the range of 0.5 mol / kg to 5 mol / kg, 1 mol / kg to 3 mol / kg in some embodiments, 1 mol / kg to 2 mol / kg in some embodiments, and specifically 1 mol / kg to 5 mol / kg.

[0027] More specifically, the aqueous electrolyte in this embodiment is formed by solvating water with a salt-based composition containing zinc chloride and manganese(II) acetate. This is because the amount of zinc chloride used is large, 10 to 30 moles per kilogram of water. After dissolving in water, the zinc chloride and manganese(II) acetate solvate with the water, promoting the formation of new coordinate bonds. Furthermore, since most of the water molecules solvate with the zinc chloride and manganese(II) acetate, the aqueous electrolyte in this embodiment consists mostly of the aforementioned ion clusters with few free water molecules.

[0028] In this embodiment of the aqueous electrolyte, CH3COO - The ion is derived from manganese(II) acetate and does not participate in coordination, [Mn(CH3COO) 2+x (H2O) n ] x- Ion clusters are formed from manganese(II) acetate CH3COO - Ions and Mn 2+ It is formed when ions coordinate with water molecules, and [ZnCl 2+x (H2O) n ] x- Ion clusters are formed when zinc chloride coordinates with water molecules, and are [Zn(H2O)6] 2+ Ion clusters are zinc chloride Zn 2+ These are formed when ions coordinate with water molecules.

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

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

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

[0032] For every kilogram of water used, the amount of zinc chloride used in the aforementioned salt system composition ranges from 10 mol to 30 mol.

[0033] In some embodiments, the range of zinc chloride used in the salt system composition is 19 mol to 30 mol per kilogram of water used.

[0034] In some specific examples, the amount of zinc chloride used is 19 moles per kilogram of water used.

[0035] For every kilogram of water used, the amount of acetate used in the aforementioned salt system composition ranges from 1 mol to 10 mol.

[0036] In some embodiments, the amount of acetate used in the salt system composition is in the range of 2 mol to 4 mol per kilogram of water used.

[0037] In some specific examples, the range of acetate usage is 2 mol to 4 mol per kilogram of water used.

[0038] For every kilogram of water used, the amount of manganese(II) salt used in the aforementioned salt system composition ranges from 0.5 mol to 5 mol.

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

[0040] In some specific cases, the amount of manganese(II) salt used ranges from 0.5 mol to 1 mol per kilogram of water used.

[0041] The aqueous electrolyte composed of this second embodiment is also CH3COO - Ions and [Zn(H2O)6] 2+ Ion clusters and [ZnCl 2+x (H2O) n ] x- Ion clusters where x ranges from 0 to 3 and n ranges from 1 to 4, and [Mn(CH3COO) 2+x (H2O) n ] x- This includes ion clusters where x is in the range of 0 to 3 and n is in the range of 1 to 4.

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

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

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

[0045] More specifically, the aqueous electrolyte in this embodiment is formed by solvating water with a salt-based composition containing zinc chloride, manganese(II) salt, and acetate. This is because the amount of zinc chloride used is large, 10 to 30 moles per kilogram of water. After dissolving in water, the zinc chloride, manganese(II) salt, and acetate solvate with water, promoting the formation of new coordination bonds. Furthermore, since most water molecules solvate with zinc chloride, manganese(II) salt, and acetate, the aqueous electrolyte in this embodiment consists mostly of the aforementioned ion clusters with few free water molecules.

[0046] In this embodiment of the aqueous electrolyte, CH3COO - The ion is derived from acetate and does not participate in coordination, [Mn(CH3COO) 2+x (H2O) n ] x- Ion clusters are the acetate CH3COO - Mn ions and manganese(II) salts 2+ It is formed when ions coordinate with water molecules, and [ZnCl 2+x (H2O) n ] x- Ion clusters are formed when zinc chloride coordinates with water molecules, and are [Zn(H2O)6] 2+ Ion clusters are zinc chloride Zn 2+ These are formed when ions coordinate with water molecules.

[0047] The zinc-ion secondary battery of the present invention comprises 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 installed on the surface of the current collector.

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

[0050] The current collector may be, but is not limited to, carbon fiber paper, carbon felt, titanium foil, or tungsten foil.

[0051] The crystalline structure of the manganese dioxide powder may include, but is not limited to, α-MnO2, β-MnO2, δ-MnO2, γ-MnO2, λ-MnO2, or R-MnO2.

[0052] Examples of the conductive powder include, but are not limited to, Super-P carbon black, acetylene black, or Ketjen black.

[0053] Examples of the binder include, but are not limited to, polyvinylidene difluoride-based binders, polytetrafluoroethylene-based binders, or carboxymethyl cellulose.

[0054] The negative electrode includes a metal sheet, which may be, but is not limited to, a zinc metal sheet, a copper metal sheet, a lead metal sheet, a tungsten (W) metal sheet, or an indium (In) metal sheet.

[0055] The separator mentioned above may include, but is not limited to, a glass fiber separator.

[0056] The following describes the electrochemical reactions that occur when the zinc-ion secondary battery of the present invention is charged or discharged.

[0057] When charging a zinc-ion secondary battery, an oxidation reaction occurs at the manganese-based positive electrode, and at the start of charging, Zn 2+ Ions deintercalate from the manganese-based cathode structure (Equation 1), and when the zinc-ion secondary battery is charged to a high voltage (approximately 1.8V), Mn(CH3COO) 2+x (H2O) n ] x- A reaction occurs in which ion clusters lose their solvation shell on the surface of the manganese cathode, resulting in Mn 2+Ions, H2O molecules and CH3COO - Ions are released (Equation 2, where x is 0 and n is 4, Mn(CH3COO)) 2+x (H2O) n ] x- (Taking ion clusters as an example). And Mn 2+ Ions react with H2O molecules to form a MnO2 solid, which is deposited on the surface of the manganese-based cathode (Equation 3).

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

[0059] JPEG0007880147000001.jpg40170

[0060] In the present invention, depending on the components of the salt composition of the aqueous electrolyte composition and the amount of zinc chloride used, [Zn(H2O)6] is added to the aqueous electrolyte composed of the aqueous electrolyte composition. 2+ Ion cluster, [ZnCl 2+x (H2O) n ] x- Ion cluster and [Mn(CH3COO) 2+x (H2O) n ] x- Ion clusters are present, and the aqueous electrolyte is mostly composed of the above ion clusters with few free water molecules, and [ZnCl 2+x (H2O) n ] x- Ion clusters are [Zn(H2O)6] in quantity. 2+ It is more dominant than ion clusters. Since aqueous electrolytes have few free water molecules, OH is produced when free water molecules are electrolyzed on the surface of the negative electrode. - As the amount decreases, the irreversible reaction Zn occurs on the surface of the negative electrode. 2+ +2OH - → The amount of Zn(OH)2 decreases, and this 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+ ions coordinate with Cl - ions, 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 benefits 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. Therefore, not only is the redox activity of the zinc-ion secondary battery not suppressed by Cl - ions, but furthermore, the irreversible dissolution of the manganese-based positive electrode is reduced. Thus, the manganese-based positive electrode has better performance.

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

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

Examples

[0065] [Example 1] According to the types and amounts of salt compositions shown in Table 1, the amounts of zinc chloride and manganese(II) acetate used were dissolved in 1 kilogram of ultrapure water at room temperature (25°C) to prepare aqueous electrolytes with concentrations shown in Table 2 after solvation. Under normal temperature and pressure conditions, a manganese dioxide positive electrode, a glass fiber separator, a zinc negative electrode, and the aqueous electrolyte were assembled into a pouch cell-type zinc-ion secondary battery. The manganese dioxide cathode was manufactured by uniformly mixing manganese dioxide powder with a crystalline structure of β-MnO2, Super-P carbon black (manufacturer: MTI Corporation, model number: Lib-SP), and polyvinylidene fluoride binder (manufacturer: MTI Corporation, model number: Lib-PVDF) in a weight ratio of 8:1:1 to form a paste-like substance. This paste-like substance was then applied to titanium foil, which served as the current collector, and dried. The zinc negative electrode is a sheet of metallic zinc.

[0066] [Examples 2-5] The difference between Examples 2-5 and Example 1 is the amount of manganese(II) acetate used. The amounts of manganese(II) acetate used in Examples 2-5 are shown in Table 1, and the concentrations of the resulting aqueous electrolytes 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 amounts of manganese(II) chloride and sodium acetate used in Example 6 are shown in Table 1, and the concentrations of the resulting aqueous electrolyte are shown in Table 2.

[0068] [Examples 7 to 9] The difference between Examples 7-9 and Example 6 lies in the amount of manganese(II) chloride and sodium acetate used. The amounts of manganese(II) chloride and sodium acetate used in Examples 7-9 are shown in Table 1, and the concentrations of the resulting aqueous electrolytes are shown in Table 2.

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

[0070] In Comparative Examples 2 to 6 and Comparative Examples 14 to 16, an aqueous electrolyte was prepared by dissolving zinc chloride and manganese(II) chloride in ultrapure water, and the amounts of zinc chloride, manganese(II) chloride, and ultrapure water used are shown in Table 1.

[0071] In Comparative Examples 7 to 9, an aqueous electrolyte was prepared by dissolving zinc chloride and sodium acetate in ultrapure water, and the amounts of zinc chloride, sodium acetate, and ultrapure water used are shown in Table 1.

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

[0073] Furthermore, for Comparative Examples 1 to 16, zinc-ion secondary batteries were manufactured using the same manufacturing method as in Example 1, with the aqueous electrolyte obtained in each comparative example. 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 resulting Raman spectra are shown in Figures 1 to 5.

[0075] According to literature on Raman spectroscopy, 175 cm² -1 ~1200cm -1 In the Raman shift of the range, 300cm -1 The characteristic peak located at [ZnCl 2+x (H2O) n ] x- This corresponds to the existence of an ion cluster where x is in the range of 0 to 3 and n is in the range of 1 to 4, at 390 cm². -1 The characteristic peak is [Zn(H2O)6]. 2+ Responding to the presence of ion clusters, 500cm -1 , 690cm -1 and 960cm -1 The characteristic peak located at CH3COO - Responding to the presence of ions, 610cm -1 The characteristic peak located at [Mn(CH3COO) 2+x (H2O) n ] x- This corresponds to the existence of an ion cluster where x is in the range of 0 to 3 and n is in the range of 1 to 4.

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

[0077] Table 1 JPEG0007880147000002.jpg143170

[0078] Table 2 JPEG0007880147000003.jpg244170 JPEG0007880147000004.jpg156170

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

[0080] As shown in Table 2 and Figures 6 to 14, the zinc-ion secondary batteries obtained in Examples 1 to 9 have high Coulomb efficiency, indicating excellent overall efficiency. The zinc-ion secondary batteries obtained in Examples 1 to 9 have high discharge ratio capacity, indicating excellent energy storage capacity. Furthermore, the zinc-ion secondary batteries obtained in Examples 1 to 9 show no significant decline in Coulomb efficiency from the 1st cycle to the 250th cycle, indicating a long cycle life.

[0081] As shown in Figure 3, the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 1 to 6 include [Mn(CH3COO) 2+x (H2O) n ] x-There are no characteristic peaks in the ion cluster. As shown in Figure 4, the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 7 to 9 include [Mn(CH3COO) 2+x (H2O) n ] x- There are no characteristic peaks in the ion cluster. As shown in Figure 5, the Raman spectra of the aqueous electrolytes obtained in Comparative Examples 10 to 16 include [Mn(CH3COO) 2+x (H2O) n ] x- There are no characteristic peaks in the ion cluster, [ZnCl 2+x (H2O) n ] x- Characteristic peaks for ion clusters are present, but their intensity is weak.

[0082] Furthermore, as shown in Table 2 and Figures 15 to 30, the zinc-ion secondary batteries obtained in Comparative Examples 1 to 9 had low discharge ratio capacity, the zinc-ion secondary battery obtained in Comparative Example 10 had reduced Coulomb efficiency, and the zinc-ion secondary batteries obtained in Comparative Examples 11 to 16 had low Coulomb efficiency from the 1st cycle to the 250th cycle, with a large rate of decay.

[0083] Therefore, when comparing the performance of the zinc-ion secondary battery obtained in the example and the zinc-ion secondary battery obtained in the comparative example, the [Mn(CH3COO)] present in the aqueous electrolyte of the present invention 2+x (H2O) n ] x- It has been proven that ion clusters can provide zinc-ion secondary batteries with superior discharge ratio capacity, Coulomb efficiency, and cycle life.

[0084] According to the above, the aqueous electrolyte composition of the present invention can provide zinc-ion secondary batteries with a higher discharge ratio capacity, a higher average Coulomb efficiency, and a longer cycle life.

[0085] While the present invention has been described in relation to what may be considered exemplary embodiments, it is understood that the invention is not limited to the disclosed embodiments and is intended to cover a variety of configurations that fall within the broadest spirit and scope of interpretation to encompass all such modifications and equivalent configurations.

[0086] The above embodiments are illustrative in illustrating the principles and effects of the present invention and do not limit it. A person skilled in the art can make some modifications and alterations to the above embodiments, provided that they do not deviate from the spirit and scope of the invention. Therefore, all modifications and alterations made by a person skilled in the art, provided that they do not deviate from the spirit of the invention, should also be considered to fall within the scope of protection of the present invention. [Industrial applicability]

[0087] The aqueous electrolyte composition and aqueous electrolyte obtained therefrom of the present invention are suitable for providing a zinc-ion secondary battery with superior performance.

Claims

1. It consists of water and salt systems, The aforementioned salt system composition consists only of zinc chloride and manganese(II) acetate. An aqueous electrolyte composition characterized in that, for every kilogram of water used, the amount of zinc chloride used in the salt composition is 19 mol, and the amount of manganese(II) acetate used in the salt composition is in the range of 1 mol to 5 mol.

2. The aqueous electrolyte composition according to claim 1, characterized in that the amount of manganese(II) acetate used in the salt composition is in the range of 1 mol to 3 mol per kilogram of water used.

3. It consists of water and salt systems, The aforementioned salt system composition consists only of zinc chloride, manganese(II) chloride, and sodium acetate. An aqueous electrolyte composition characterized in that, for every kilogram of water used, the amount of zinc chloride used in the salt system composition is 19 mol, the amount of manganese(II) chloride used in the salt system composition is in the range of 0.5 mol to 1 mol, and the amount of sodium acetate used in the salt system composition is in the range of 2 mol to 4 mol.

4. The aqueous electrolyte composition according to any one of claims 1 to 3 is solvated, [Zn(H ２ O) ６ ] ２＋ Ion clusters and [ZnCl ２＋ｘ (H ２ O) ｎ ] ｘ－ An ion cluster in which x ranges from 0 to 3 and n ranges from 1 to 4, [Mn(CH ３ COO) ２＋ｘ (H ２ O) ｎ ｘ－ An ion cluster wherein the range of x is 0 to 3 and the range of n is 1 to 4, and an aqueous electrolyte comprising the same.

5. A zinc-ion secondary battery comprising a manganese-based positive electrode, a negative electrode installed at a distance from the manganese-based positive electrode, and the aqueous electrolyte according to claim 4 in contact with the manganese-based positive electrode and the negative electrode.

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