Aqueous electrolyte, preparation method thereof and aqueous battery

Abstract

The invention discloses an aqueous electrolyte, a preparation method thereof and an aqueous battery, belongs to the technical field of aqueous batteries, and solves the problems that an electrolyte of an aqueous battery in the prior art is easy to corrode an aluminum current collector and the application of the aluminum current collector in the aqueous battery is limited. The aqueous electrolyte comprises the following components: electrolyte salt, a regulator, a corrosion inhibitor, a separant and water; wherein the electrolyte salt is sulfate, and the regulator is weak acid salt. By adopting the aqueous electrolyte provided by the invention, the cycle life of the battery can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of aqueous batteries, and in particular to an aqueous electrolyte, a preparation method thereof, and an aqueous battery. Background Art

[0002] Aqueous batteries are environmentally friendly, safe and reliable batteries. Due to their unique advantages, aqueous batteries have received more and more attention and recognition. The electrolyte of aqueous batteries is crucial to the performance of aqueous batteries. At present, aqueous battery electrolytes face many complex problems, such as pH instability, narrow voltage window, corrosion of current collectors, dissolution of active materials, etc. Aluminum has many advantages as a current collector for aqueous batteries, such as high conductivity, low cost, and low density. However, the strong corrosiveness of aluminum in aqueous electrolytes hinders the application of aluminum current collectors. Therefore, how to solve the corrosion of aluminum current collectors is the key to solving the long-life aqueous battery. Summary of the invention

[0003] In view of the above situation, the present invention aims to provide an aqueous electrolyte, a preparation method thereof and an aqueous battery, which are used to solve one of the following technical problems: the electrolyte of the existing aqueous battery is easy to corrode the aluminum current collector, limiting the application of the aluminum current collector in the aqueous battery.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] On the one hand, the present invention provides an aqueous electrolyte, the components of which include: an electrolyte salt, a regulator, a corrosion inhibitor, a separator and water; wherein the electrolyte salt is a sulfate and the regulator is a weak acid salt.

[0006] Furthermore, the regulator is a weak chromium salt.

[0007] Furthermore, the regulator is chromium-containing acetate and / or phosphate.

[0008] Furthermore, the corrosion inhibitor is one or more of diphthalic acid urea, benzotriazole, mercaptobenzothiazole, disodium chlorophosphate, hexadecylamine and m-nitrophenol.

[0009] Furthermore, the release agent is immiscible with water.

[0010] Furthermore, the density of the release agent is less than 0.95 g / cm 3 .

[0011] Furthermore, the concentration of the regulator is 0.05-0.5 mol / L.

[0012] Furthermore, the mass of the corrosion inhibitor accounts for 0.05% to 0.5% of the total mass of the aqueous electrolyte.

[0013] The present invention also provides a method for preparing an aqueous electrolyte, comprising: mixing an electrolyte salt, a regulator, a corrosion inhibitor and water, performing a deoxygenation treatment, and then adding a separator.

[0014] The present invention also provides an aqueous battery, which includes the aqueous electrolyte.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0016] a) The electrolyte salt of the aqueous electrolyte of the present invention is sulfate, which is stable and has high ion conductivity. The high ion concentration solution has high conductivity, reduces the battery ion impedance, and can optimize the rate performance; the regulator is a weak acid salt, and the product of its weak acid radical ion hydrolysis is a weak acid and OH-, and no precipitation is produced. It has the function of adjusting the pH of the reaction interface, so that even if hydrogen evolution and oxygen evolution reactions occur at the positive electrode / negative electrode current collector interface, a neutral environment can be maintained, and the interface is prevented from being corroded in a strong acid or strong base environment, so that the aluminum current collector can be used in aqueous batteries.

[0017] b) The regulator of the aqueous electrolyte of the present invention is a chromium-containing weak acid salt. In the aqueous electrolyte, chromium ions will form a dense chromium oxide layer on the surface of the aluminum current collector under the action of the electric field. The chromium oxide has stable chemical properties and strong corrosion resistance, which can fully protect the aluminum current collector from corrosion.

[0018] c) The aqueous electrolyte of the present invention introduces a trace amount of corrosion inhibitor, which can be adsorbed on the surface of the aluminum collector to form a protective isolation layer, isolating the aluminum material from water, further inhibiting the corrosion of the aluminum collector; the isolation agent of the aqueous electrolyte has a density lower than that of the electrolyte and is insoluble in water. It will float on the upper layer, isolating the electrolyte from the air to avoid corrosion of the collector due to the entry of oxygen. In addition, the aluminum collector tab of the aqueous battery is very susceptible to chemical corrosion and fracture at the water / air interface. The isolation agent isolates the aqueous electrolyte from oxygen at the interface, and the aluminum collector tab is effectively protected; the isolation agent can effectively inhibit the "salt climbing" phenomenon of the aqueous electrolyte.

[0019] d) The aqueous electrolyte of the present invention does not introduce flammable organic solvents, which ensures the intrinsic safety of aqueous batteries, environmental protection, convenience and simple preparation. The voltage window of the aqueous electrolyte of the present invention is above 2.4V, which significantly broadens the voltage window of the aqueous electrolyte.

[0020] e) The aqueous battery of the present invention can effectively alleviate or even avoid the corrosion of the aluminum current collector, and further extend the cycle life of the aqueous battery. For example, the capacity retention rate after 100 cycles is greater than 88%. The aqueous battery of the present invention has excellent cycle performance.

[0021] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0023] Figure 1 The full battery aging test results of Example 1 and Comparative Example 1 are shown in FIG.

[0024] Figure 2 This is a graph showing the LSV test results of the electrolyte prepared in Example 1;

[0025] Figure 3 This is a SEM test result of the disassembled current collector of the battery in Example 1;

[0026] Figure 4 This is a SEM test image of the current collector of the battery disassembled in Comparative Example 1;

[0027] Figure 5 This is the charge and discharge curve of the first cycle of the full battery in Example 5. DETAILED DESCRIPTION

[0028] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0029] The invention provides an aqueous electrolyte, the components of which include: electrolyte salt, regulator, corrosion inhibitor, separator and water; wherein the electrolyte salt is sulfate and the regulator is a weak acid salt.

[0030] Specifically, the electrolyte salt in the above-mentioned aqueous electrolyte is sulfate, which is stable and has high ion conductivity. The high ion concentration solution has high conductivity, reduces the battery ion impedance, and can optimize the rate performance; the regulator is a weak acid salt, and the product of its weak acid radical ion hydrolysis is weak acid and OH-, and no precipitation is produced. It has the function of adjusting the pH of the reaction interface, so that the positive electrode / negative electrode current collector interface can maintain a neutral environment even if hydrogen evolution and oxygen evolution reactions occur, avoiding corrosion of the interface in a strong acid or strong base environment, so that the aluminum current collector can be used in aqueous batteries.

[0031] Specifically, in order to prevent contamination by impurities, deionized water may be used.

[0032] Specifically, the raw material of the electrolyte salt is hydrated sulfate, such as one or more of Li2SO4·H2O, Na2SO4·10H2O, ZnSO4·7H2O, MgSO4·7H2O and K2SO4·10H2O. Using hydrated sulfate as electrolyte salt has the following advantages: hydrated sulfate has high solubility, high ion concentration solution has high conductivity, reduces battery ion impedance, and optimizes rate performance; and SO4 2- Its inherent stability does not - , Cl - 、F - Br - 、NO3 - Plasma will mainly attack the aluminum surface, causing aluminum to dissolve; thirdly, sulfate is cheap and can reduce the cost of electrolyte manufacturing.

[0033] Specifically, if the concentration of the above-mentioned electrolyte salt is too high, the solubility of the electrolyte salt is limited, and the regulator cannot be dissolved in the electrolyte; if the concentration is too low, the conductivity of the electrolyte decreases and the impedance increases; therefore, the concentration of the electrolyte salt is controlled to be 0.5-5 mol / L, for example, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, and 4.5 mol / L.

[0034] Specifically, the regulator is a chromium-containing weak acid salt. In the aqueous electrolyte, chromium ions will form a dense chromium oxide layer on the surface of the aluminum current collector under the action of the electric field. The chromium oxide has stable chemical properties and strong corrosion resistance, which can fully protect the aluminum current collector from corrosion.

[0035] Specifically, the above-mentioned regulator is chromium-containing acetate and / or phosphate. For example, the regulator is one or more of chromium acetate, chromium oxalate and chromium dihydrogen phosphate.

[0036] Considering that if the concentration of the regulator is too high, the conductivity of the electrolyte will be low due to the low conductivity of the weak acid salt solution; if the concentration of the regulator is too low, the weak acid and weak acid radicals cannot fully adjust the pH of the reaction interface, resulting in corrosion of the aluminum collector; therefore, the concentration of the regulator is controlled to be 0.05-0.5 mol / L. For example, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L.

[0037] Specifically, the corrosion inhibitor is one or more of diphthalic acid urea, benzotriazole, mercaptobenzothiazole, disodium chlorophosphonate, hexadecylamine and m-nitrophenol. Trace corrosion inhibitors can be adsorbed on the surface of aluminum current collectors to form a protective layer, and the aluminum material is isolated from water, which further inhibits the corrosion of the aluminum current collector; therefore, the mass of the corrosion inhibitor is controlled to account for 0.05% to 0.5% of the total mass of the aqueous electrolyte, such as 0.1%, 0.2%, 0.3%, and 0.4%.

[0038] Specifically, the above-mentioned release agent is immiscible with water.

[0039] Specifically, the density of the above-mentioned release agent is less than 0.95g / cm 3 The release agent is selected from one or more of benzene, toluene, xylene, ethyl acetate, butyl acetate, n-amyl acetate, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether.

[0040] Specifically, the above-mentioned isolating agent has a density lower than that of the electrolyte and is insoluble in water. It will float on the upper layer, isolating the electrolyte from the air and avoiding corrosion of the current collector due to the entry of oxygen. In addition, the aluminum current collector tabs of the aqueous battery are very susceptible to chemical corrosion and fracture at the water / air interface. The isolating agent isolates the aqueous electrolyte from oxygen at the interface, and the aluminum current collector tabs are effectively protected. The isolating agent can effectively inhibit the "salt climbing" phenomenon of the aqueous electrolyte.

[0041] Considering that if the mass proportion of the isolating agent is too high, the cost will increase, and if the mass proportion is too low, it will not be able to isolate the air, resulting in metal corrosion at the three-phase interface. Therefore, the mass proportion of the isolating agent to the total mass of the aqueous electrolyte is controlled to be 3% to 10%, such as 4%, 5%, 6%, 7%, 8%, and 9%.

[0042] Specifically, if the viscosity of the electrolyte is too high, the ion transport resistance increases, the ion conductivity of the electrolyte is low, and the battery impedance increases. The viscosity of the aqueous electrolyte of the present invention does not exceed 20 mPa / s.

[0043] Specifically, the pH of the aqueous electrolyte is 7.0-8.0.

[0044] Specifically, the conductivity of the aqueous electrolyte is ≥50mS / cm.

[0045] Specifically, the voltage window of the aqueous electrolyte is above 2.4 V (eg, 2.45 to 2.8 V), which significantly broadens the voltage window of the aqueous electrolyte.

[0046] The present invention also provides a method for preparing the aqueous electrolyte, comprising: mixing electrolyte salt, a regulator, a corrosion inhibitor and water, performing a deoxygenation treatment, and then adding a separator.

[0047] Specifically, the above deoxygenation step includes:

[0048] S1. Activated carbon adsorption: put the activated carbon cotton into the prepared mixed solution, let it stand for 5 to 10 hours and then take it out;

[0049] S2, nitrogen: nitrogen is introduced from the bottom of the mixed liquid, and the nitrogen cleaning time is 0.5 to 2 hours;

[0050] S3. Vacuuming: let the mixed liquid after nitrogen gas is passed through stand at a pressure of -0.09 to -0.1 MPa for 5 to 10 hours, and add the isolation agent in the vacuum environment.

[0051] The present invention also provides an aqueous battery comprising the aqueous electrolyte.

[0052] Specifically, the aqueous battery can be one or more of an aqueous lithium ion battery, an aqueous sodium ion battery, an aqueous potassium ion battery, an aqueous zinc ion battery and an aqueous magnesium ion battery.

[0053] Specifically, the current collectors of the positive and negative electrodes of the above aqueous battery are both aluminum foil.

[0054] Specifically, the preparation method of the aqueous battery includes the following steps: assembling the electrode, diaphragm and current collector required for the aqueous battery into a battery cell and incorporating them into a shell, injecting an appropriate amount of the above-mentioned electrolyte, and then sealing and standing to obtain the aqueous battery.

[0055] Compared with the prior art, the electrolyte salt of the aqueous electrolyte of the present invention is sulfate, which is stable and has high ion conductivity. The high ion concentration solution has high conductivity, reduces the battery ion impedance, and can optimize the rate performance; the regulator is a weak acid salt, and the products of its weak acid radical ions after hydrolysis are weak acid and OH-, and no precipitation is produced. It has the function of adjusting the pH of the reaction interface, so that the positive electrode / negative electrode current collector interface can maintain a neutral environment even if hydrogen evolution and oxygen evolution reactions occur, avoiding corrosion of the interface in a strong acid or strong base environment, so that the aluminum current collector can be used in aqueous batteries.

[0056] The regulator of the aqueous electrolyte of the present invention is a chromium-containing weak acid salt. In the aqueous electrolyte, chromium ions will form a dense chromium oxide layer on the surface of the aluminum current collector under the action of the electric field. The chromium oxide has stable chemical properties and strong corrosion resistance, and fully protects the aluminum current collector from corrosion.

[0057] The aqueous electrolyte of the present invention introduces a trace amount of corrosion inhibitor, which can be adsorbed on the surface of the aluminum current collector to form a protective layer, thereby isolating the aluminum material from water and further inhibiting the corrosion of the aluminum current collector. The isolation agent of the aqueous electrolyte has a density lower than that of the electrolyte and is insoluble in water. It floats on the upper layer, isolating the electrolyte from the air and avoiding corrosion of the current collector due to the entry of oxygen. In addition, the aluminum current collector tab of the aqueous battery is very susceptible to chemical corrosion and fracture at the water / air interface. The isolation agent isolates the aqueous electrolyte from oxygen at the interface, and the aluminum current collector tab is effectively protected. The isolation agent can effectively inhibit the "salt climbing" phenomenon of the aqueous electrolyte.

[0058] The aqueous electrolyte of the present invention does not introduce flammable organic solvents, thereby ensuring the intrinsic safety of the aqueous battery, environmental protection, convenience and simple preparation.

[0059] The voltage window of the aqueous electrolyte of the present invention is above 2.4V, which significantly broadens the voltage window of the aqueous electrolyte.

[0060] The aqueous battery of the present invention can effectively alleviate or even avoid the corrosion of the aluminum current collector, and further extend the cycle life of the aqueous battery.

[0061] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0062] Example 1

[0063] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0064] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0065] Lithium sulfate monohydrate, chromium acetate, benzotriazole and deionized water are mixed and stirred uniformly, deoxygenated, and then ethyl acetate is added; wherein the concentration of lithium sulfate is 2 mol / L, the concentration of chromium acetate is 0.25 mol / L, the mass proportion of benzotriazole is 0.05%, and the mass proportion of ethyl acetate is 5%.

[0066] The deoxygenation treatment includes: placing activated carbon cotton into the prepared mixed liquid, taking it out after standing for 6 hours; introducing nitrogen from the bottom of the mixed liquid, and the nitrogen cleaning time is 1 hour; and the mixed liquid after nitrogen is passed is allowed to stand at a pressure of -0.1MPa for 5 hours.

[0067] The aqueous battery of this embodiment includes the above aqueous battery electrolyte, and the preparation method of the aqueous battery includes the following steps:

[0068] An aqueous lithium-ion LiMn2O4 / / LiTi2(PO4)3 battery material system is adopted, and the positive and negative electrode sheets are prepared by slurry coating. The positive and negative electrode collectors are both made of 20μm thick aluminum foil. The positive and negative electrode sheets and separators are assembled in the order of positive electrode sheet, separator, negative electrode sheet, separator, positive electrode sheet, separator and negative electrode sheet to assemble the aqueous lithium-ion LiMn2O4 / / LiTi2(PO4)3 battery cell. Then, the above-mentioned aqueous electrolyte is injected, the mixture is sealed and left to stand to obtain an aqueous battery.

[0069] The voltage window of the aqueous electrolyte in this embodiment is 2.5V, which significantly broadens the voltage window of the aqueous electrolyte.

[0070] The battery was left to stand for 20 hours before testing, and the test current density was 100 mA / g (based on the mass of the negative electrode active material); Figure 1 As shown, the material's discharge specific capacity reaches 92 mAh / g, showing a relatively high specific capacity; the battery has a capacity retention rate of 97.8% after 100 cycles, and a coulombic efficiency of >99.5%, showing excellent life performance.

[0071] Example 2

[0072] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0073] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0074] Sodium sulfate decahydrate, chromium dihydrogen phosphate, m-nitrophenol and deionized water are mixed and stirred uniformly, deoxygenated, and then xylene is added; the concentration of sodium sulfate is 1 mol / L, the concentration of chromium dihydrogen phosphate is 0.1 mol / L, the mass proportion of m-nitrophenol is 0.1%, and the mass proportion of xylene is 8%.

[0075] The deoxygenation treatment includes: placing activated carbon cotton into the prepared mixed liquid, taking it out after standing for 8 hours; introducing nitrogen from the bottom of the mixed liquid, and the nitrogen cleaning time is 0.5 hours; and the mixed liquid after nitrogen is passed is allowed to stand at a pressure of -0.1MPa for 8 hours.

[0076] The aqueous battery of this embodiment includes the above aqueous battery electrolyte, and the preparation method of the aqueous battery includes the following steps:

[0077] Using aqueous sodium ion Na 0.44 The MnO2 / / NaTi2(PO4)3 battery material system is prepared by slurry coating. The positive and negative electrode sheets are prepared by 20μm thick aluminum foil. The positive and negative electrode sheets and separators are assembled in the order of positive electrode sheet, separator, negative electrode sheet, separator, positive electrode sheet, separator, and negative electrode sheet. 0.44MnO2 / / NaTi2(PO4)3 battery cell, and then inject the above-mentioned aqueous electrolyte and seal it and let it stand to obtain an aqueous battery.

[0078] The voltage window of the aqueous electrolyte in this embodiment is 2.58V, which significantly broadens the voltage window of the aqueous electrolyte.

[0079] The battery prepared in Example 2 was tested and cycled at a rate of 1C. After 100 normal cycles, the capacity retention rate was 95.2%, the coulombic efficiency was >99.5%, the aluminum current collector was not corroded, and the battery had excellent cycle performance.

[0080] Example 3

[0081] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0082] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0083] Sodium sulfate decahydrate, chromium acetate, mercaptobenzothiazole and deionized water are mixed and stirred uniformly, deoxygenated, and then toluene is added; wherein the concentration of sodium sulfate is 2 mol / L, the concentration of chromium acetate is 0.5 mol / L, the mass proportion of m-nitrophenol is 0.2%, and the mass proportion of toluene is 3%.

[0084] The steps of deoxygenation treatment are the same as those in Example 1 and will not be repeated here.

[0085] The aqueous battery of this embodiment includes the above aqueous battery electrolyte, and the preparation method of the aqueous battery includes the following steps:

[0086] Using aqueous sodium ion Na 0.44 The MnO2 / / NaTi2(PO4)3 battery material system is prepared by slurry coating. The positive and negative electrode sheets are prepared by 20μm thick aluminum foil. The positive and negative electrode sheets and separators are assembled in the order of positive electrode sheet, separator, negative electrode sheet, separator, positive electrode sheet, separator, and negative electrode sheet. 0.44 MnO2 / / NaTi2(PO4)3 battery cell, and then inject the above-mentioned aqueous electrolyte and seal it and let it stand to obtain an aqueous battery.

[0087] The voltage window of the aqueous electrolyte in this embodiment is 2.71 V, which significantly broadens the voltage window of the aqueous electrolyte.

[0088] The battery prepared in Example 3 was tested and cycled at different rates of 0.5C, 1C, 2C, and 5C. Based on the mass of the negative electrode active material, the specific capacity at 0.5C was 98.7 mAh / g, the specific capacity at 1C was 92.1 mAh / g, the specific capacity at 2C was 85.7 mAh / g, and the specific capacity at 5C was 75.1 mAh / g. The full battery had excellent rate performance.

[0089] Example 4

[0090] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0091] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0092] Sodium sulfate decahydrate, chromium oxalate, benzotriazole and deionized water are mixed and stirred uniformly, deoxygenated, and then ethylene glycol monoethyl ether is added; wherein the concentration of sodium sulfate is 2 mol / L, the concentration of chromium oxalate is 0.3 mol / L, the mass proportion of benzotriazole is 0.08%, and the mass proportion of ethylene glycol monoethyl ether is 6%.

[0093] The steps of deoxygenation treatment are the same as those in Example 1 and will not be repeated here.

[0094] The aqueous battery of this embodiment includes the above aqueous battery electrolyte, and the preparation method of the aqueous battery includes the following steps:

[0095] An aqueous sodium ion NaHCF / / NaTi2(PO4)3 battery material system is adopted, and the positive and negative electrode sheets are prepared by slurry coating. The positive and negative electrode collectors are both made of 20μm thick aluminum foil. The positive and negative electrode sheets and separators are assembled in the order of positive electrode sheet, separator, negative electrode sheet, separator, positive electrode sheet, separator and negative electrode sheet to assemble a lithium ion NaHCF / / NaTi2(PO4)3 battery cell. Then the above-mentioned aqueous electrolyte is injected and the battery is sealed and left to stand to obtain an aqueous battery.

[0096] The voltage window of the aqueous electrolyte in this embodiment is 2.45V, which significantly broadens the voltage window of the aqueous electrolyte.

[0097] The battery prepared in Example 4 was tested and cycled at a rate of 1C for 100 normal cycles. The detected capacity retention rate was 96.7%, and the coulombic efficiency was greater than 99.2%, showing excellent cycle performance.

[0098] Example 5

[0099] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0100] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0101] Zinc sulfate hydrate, chromium acetate, m-nitrophenol and deionized water are mixed and stirred evenly, and then deoxygenated, and then n-amyl acetate is added; the concentration of zinc sulfate is 4 mol / L, the concentration of chromium acetate is 0.2 mol / L, the mass proportion of m-nitrophenol is 0.42%, and the mass proportion of n-amyl acetate is 4%.

[0102] The steps of deoxygenation treatment are the same as those in Example 1 and will not be repeated here.

[0103] The aqueous battery of this embodiment includes the above aqueous battery electrolyte, and the preparation method of the aqueous battery includes the following steps:

[0104] An aqueous sodium ion MnO2 / / Zn battery material system is adopted, and the positive electrode is prepared by slurry coating. A 20μm thick aluminum foil is used as the positive electrode collector, and a zinc sheet is used as the negative electrode. The positive and negative electrode sheets and separators are assembled in the order of positive electrode sheet, separator, negative electrode sheet, separator, positive electrode sheet, separator and negative electrode sheet to assemble a lithium ion MnO2 / / Zn battery cell. Then the above-mentioned aqueous electrolyte is injected and the battery is sealed and left to stand to obtain an aqueous battery.

[0105] The voltage window of the aqueous electrolyte in this embodiment is 2.67V, which significantly broadens the voltage window of the aqueous electrolyte.

[0106] The battery prepared in Example 5 was tested and cycled at a rate of 1C. Figure 5 As shown, the discharge capacity of the MnO2 positive electrode in the first cycle reached 228 mAh / g, and the coulombic efficiency was 97.8%; after 100 normal cycles, the detected capacity retention rate was 88.9%.

[0107] Example 6

[0108] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0109] The preparation method of the aqueous electrolyte of this embodiment includes the following steps: lithium sulfate monohydrate, chromium oxalate, benzotriazole, and deionized water are mixed and stirred evenly, deoxygenated, and then toluene is added; wherein the concentration of lithium sulfate monohydrate is 1.5 mol / L, the concentration of chromium oxalate is 0.1 mol / L, the mass proportion of benzotriazole is 0.05%, and the mass proportion of toluene is 5%.

[0110] The steps of deoxygenation treatment are the same as those in Example 1 and will not be repeated here.

[0111] The aqueous battery of this embodiment includes the above-mentioned aqueous battery electrolyte. The preparation method of the aqueous battery is the same as that of Example 1 and will not be repeated here.

[0112] The voltage window of the aqueous electrolyte in this embodiment is 2.55V, which significantly broadens the voltage window of the aqueous electrolyte.

[0113] The battery was tested after standing for 20 hours, with a test current density of 100mA / g (based on the mass of the negative electrode active material); the material discharge specific capacity reached 95.3mAh / g, showing a relatively high specific capacity; the battery had a capacity retention rate of 95.1% after 100 cycles, and a coulombic efficiency of >99.5%, showing excellent life performance.

[0114] Example 7

[0115] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0116] The preparation method of the aqueous electrolyte of this embodiment comprises the following steps:

[0117] Lithium sulfate monohydrate, chromium acetate, diphthalic acid urea and deionized water are mixed and stirred uniformly, deoxygenated, and then ethylene glycol monoethyl ether is added; wherein the concentration of lithium sulfate is 1.0 mol / L, the concentration of chromium acetate is 0.5 mol / L, the mass proportion of diphthalic acid urea is 0.3%, and the mass proportion of ethylene glycol monoethyl ether is 4.2%.

[0118] The steps of deoxygenation treatment are the same as those in Example 1 and will not be repeated here.

[0119] The aqueous battery of this embodiment includes the above-mentioned aqueous battery electrolyte. The preparation method of the aqueous battery is the same as that of Example 1 and will not be repeated here.

[0120] The voltage window of the aqueous electrolyte in this embodiment is 2.61V, which significantly broadens the voltage window of the aqueous electrolyte.

[0121] The battery was tested after standing for 20 hours, with a test current density of 100mA / g (based on the mass of the negative electrode active material); the material discharge specific capacity reached 101.4mAh / g, showing a relatively high specific capacity; the battery had a capacity retention rate of 94.8% after 100 cycles, and a coulombic efficiency of >99.5%, showing excellent life performance.

[0122] Example 8

[0123] This embodiment provides an aqueous electrolyte, a preparation method thereof, and an aqueous battery.

[0124] The preparation method of the aqueous electrolyte of this embodiment includes the following steps: sodium sulfate decahydrate, chromium dihydrogen phosphate, benzotriazole, and deionized water are mixed and stirred evenly, deoxygenated, and then ethyl acetate is added; wherein the concentration of sodium sulfate decahydrate is 1.2 mol / L, the concentration of chromium dihydrogen phosphate is 0.25 mol / L, the mass proportion of benzotriazole is 0.15%, and the mass proportion of ethyl acetate is 7.5%.

[0125] The steps of deoxygenation treatment are the same as those in Example 2 and will not be repeated here.

[0126] The aqueous battery of this embodiment includes the above-mentioned aqueous battery electrolyte. The preparation method of the aqueous battery is the same as that of Example 2 and will not be repeated here.

[0127] The voltage window of the aqueous electrolyte in this embodiment is 2.48V, which significantly broadens the voltage window of the aqueous electrolyte.

[0128] The battery was tested after standing for 20 hours. The test current density was 100mA / g (based on the mass of the negative electrode active material). The material discharge specific capacity reached 94.6mAh / g, showing a relatively high specific capacity. The battery had a capacity retention rate of 96.6% after 100 cycles, and a coulombic efficiency of >99.5%, showing excellent life performance.

[0129] Comparative Example 1:

[0130] This comparative example provides an electrolyte, a preparation method thereof, and an aqueous battery.

[0131] The electrolyte of this comparative example includes 2 mol / L lithium sulfate and deionized water, and does not contain a regulator, a corrosion inhibitor, or a separator.

[0132] Comparative Example 2:

[0133] This comparative example provides an electrolyte, a preparation method thereof, and an aqueous battery.

[0134] This comparative example is basically the same as Example 1, except that no separator is added to the electrolyte.

[0135] Comparative Example 3:

[0136] This comparative example provides an electrolyte, a preparation method thereof, and an aqueous battery.

[0137] This comparative example is substantially the same as Example 1, except that the concentration of lithium sulfate is 2 mol / L, the concentration of chromium acetate is 1.0 mol / L, the mass proportion of benzotriazole is 0.02%, and the mass proportion of ethyl acetate is 1%.

[0138] The performances of the embodiments and comparative examples are shown in Table 1 below. It can be seen that the ionic conductivity of the aqueous electrolyte of the present invention is greater than 60 mS / cm, for example, 60.8 to 105.8 mS / cm. The ionic conductivity of the electrolyte in Example 1 is as high as 105.8 mS / cm, which is much greater than the ionic conductivity of the electrolyte in the comparative example. The aluminum current collector of the full battery of the present invention is free of corrosion, and the capacity retention rate after 100 cycles is greater than 88%, for example, 88.9% to 98%. The aqueous battery of the present invention has excellent cycle performance.

[0139] Table 1 Performance data of embodiments and comparative examples

[0140]

[0141]

[0142] Figure 1 This is a graph showing the full-battery aging test results for Example 1 and Comparative Example 1. It can be seen that after 100 cycles at a test current density of 100 mA / g, the full-battery capacity retention rate of Example 1 is 97.8%, and the coulombic efficiency is greater than 99.5%. The full-battery capacity retention rate of Comparative Example 1 is only 55.2%, and the coulombic efficiency is less than 99%. The battery cycle performance of Example 1 is significantly inferior to that of Comparative Example 1.

[0143] Figure 2 The LSV test result diagram of the electrolyte prepared in Example 1 shows that the voltage window of the electrolyte is 2.5V, which significantly broadens the voltage window of the aqueous electrolyte (1.6V).

[0144] Figure 3 This is the SEM test result of the disassembled current collector of the battery in Example 1. It can be seen that after 100 cycles, there is no damage or breakage on the surface of the aluminum current collector. The electrolyte fully protects the surface of the aluminum current collector and improves its corrosion resistance.

[0145] Figure 4 This is the SEM test picture of the disassembled current collector of the battery in comparative example 1. It can be seen that after the full battery has been cycled 100 times, cracks and breakages have appeared in the aluminum current collector. This is due to the corrosion of the aluminum current collector, which in turn leads to the deterioration of battery performance.

[0146] Figure 5 This is the charge and discharge curve of the first cycle of the full battery in Example 5.

[0147] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An aqueous electrolyte, characterized in that: The components of the aqueous electrolyte include: electrolyte salt, regulator, corrosion inhibitor, separator and water; wherein the electrolyte salt is sulfate and the regulator is a weak acid salt.

2. The aqueous electrolyte according to claim 1, characterized in that The regulator is a weak chromium salt.

3. The aqueous electrolyte according to claim 2, characterized in that: The regulator is chromium-containing acetate and / or phosphate.

4. The aqueous electrolyte according to claim 1, characterized in that The corrosion inhibitor is one or more of diphthalic acid urea, benzotriazole, mercaptobenzothiazole, disodium chlorophosphonate, hexadecylamine and m-nitrophenol.

5. The aqueous electrolyte according to claim 1, characterized in that: The release agent is immiscible with water.

6. The aqueous electrolyte according to claim 1, characterized in that The density of the release agent is less than 0.95 g / cm 3 .

7. The aqueous electrolyte according to claim 1, characterized in that: The concentration of the regulator is 0.05-0.5 mol / L.

8. The aqueous electrolyte according to claim 1, characterized in that The mass of the corrosion inhibitor accounts for 0.05% to 0.5% of the total mass of the aqueous electrolyte.

9. A method for preparing an aqueous electrolyte according to any one of claims 1 to 8, characterized in that: include: Electrolyte salt, regulator, corrosion inhibitor and water are mixed and deoxidized, and then the separator is added.

10. An aqueous battery, characterized in that: The aqueous battery comprises the aqueous electrolyte according to any one of claims 1 to 8 or the aqueous electrolyte prepared by the preparation method according to claim 9.

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