An electrolyte for an aqueous battery, a preparation method thereof, and an aqueous battery

Abstract

The present invention discloses an electrolyte for an aqueous battery, a preparation method thereof, and an aqueous battery, belonging to the technical field of aqueous batteries, and solves the problems of the matching limitation between the electrolyte of the aqueous battery and the amphoteric current collector in the prior art, and the easy corrosion of the amphoteric current collector by the electrolyte, resulting in easy damage to the battery. The components of the electrolyte for the aqueous battery include: a solvent, an electrolyte salt, an additive, and an acid-base buffer; wherein, the electrolyte salt includes a strong acid radical salt and a weak acid radical salt, and the additive includes a stabilizer, an antioxidant, and a surfactant. Using the electrolyte for the aqueous battery of the present invention can extend the cycle life of the battery.

Description

Technical Field

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

[0002] The electrochemical performance of an aqueous battery is closely related to its electrolyte, and the components of the electrolyte determine the type and service life of the current collector, etc. Due to different types of aqueous batteries, the components and pH of the electrolyte change accordingly, thus restricting the selection and protection of the current collector. Sometimes, due to factors such as the type of aqueous battery and the overpotential of the current collector, the selection of the electrolyte is full of limitations. For example, it is necessary to change the solute type, reduce the ionic conductivity of the electrolyte, increase the freezing point of the solution, change the pH value, etc. to match the selected current collector, which greatly restricts the development of aqueous batteries. Summary of the Invention

[0003] In view of the above situation, the present invention aims to provide an electrolyte for an aqueous battery, a preparation method thereof, and an aqueous battery to solve one of the following technical problems: the matching limitation between the electrolyte of the existing aqueous battery and the amphoteric current collector, and the problem that the electrolyte easily corrodes the amphoteric current collector, resulting in easy damage to the battery.

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

[0005] On the one hand, the present invention provides an electrolyte for an aqueous battery. The components of the electrolyte for an aqueous battery include: a solvent, an electrolyte salt, an additive, and an acid-base buffer; wherein, the electrolyte salt includes a strong acid radical salt and a weak acid radical salt, and the additive includes a stabilizer, an antioxidant, and a surfactant.

[0006] Further, the solvent includes water and an organic solvent.

[0007] Further, the strong acid radical salt is one or more of sulfate, nitrate, aminosulfonate, trifluoromethylsulfonate, fluoride, chlorate, perchlorate, and permanganate.

[0008] Further, the weak acid radical salt is one or more of carbonate, bicarbonate, acetate, sulfite, bisulfite, phosphate, hydrogen phosphate, dihydrogen phosphate, oxalate, and silicate.

[0009] Further, the stabilizer is one or more of phosphate, sodium citrate, tartrate, glycinate, polyvinyl alcohol, polyacrylic acid, magnesium succinate, and sodium dehydrocholate.

[0010] Further, the antioxidant is one or more of ascorbic acid, tea polyphenols, butylated hydroxyanisole, dibutylhydroxytoluene, tert-butylhydroquinone, tert-butyl hydroquinone, citric acid, EDTA, and ascorbyl palmitate.

[0011] Further, the concentration of the strong acid radical salt is 0.5 - 18 mol / L.

[0012] Further, the concentration of the weak acid radical salt is 0.1 - 6 mol / L.

[0013] On the other hand, the present invention also provides a method for preparing the electrolyte for the above aqueous battery, including:

[0014] Step 1: Mix water and an organic solvent to obtain a mixed solvent;

[0015] Step 2: Add an electrolyte salt to the mixed solvent and mix to obtain Solution A;

[0016] Step 3: Add a stabilizer, an antioxidant, and a surfactant to Solution A in sequence and mix to obtain Solution B;

[0017] Step 4: Add an acid-base buffer to Solution B and adjust the pH of Solution B to neutral to obtain the electrolyte for the aqueous battery.

[0018] The present invention also provides an aqueous battery, and the aqueous battery includes the above electrolyte for the aqueous battery.

[0019] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0020] a) The electrolyte salt of the electrolyte for the aqueous battery of the present invention includes a strong acid radical salt and a weak acid radical salt. The main salt of the electrolyte solution is the strong acid radical salt, which can be completely ionized after being completely dissolved, providing a rich ion concentration for the electrolyte solution, thereby increasing the ionic conductivity and ionic transport rate of the electrolyte solution, further accelerating the electrochemical reaction rate, and also reducing the adverse effects caused by concentration polarization to a certain extent; the secondary salt of the electrolyte solution is the weak acid radical salt. After being completely dissolved, the weak acid radical can undergo partial hydrolysis. When an amphoteric metal is used as the current collector in the aqueous battery, the weak acid radical hydrated ions formed by the solvation of the weak acid radical enable the weak acid radical to act as a medium between the current collector and H 2 O, isolating the direct contact between the metal hydrated ions in the electrolyte solution and the current collector, thereby avoiding the corrosion of the current collector and slowing down the gas evolution behavior of the electrolyte solution without affecting ion exchange, and prolonging the cycle life of the battery.

[0021] b) By adding an appropriate amount of stabilizer to the electrolyte for the aqueous battery of the present invention, the balance between solvents in the electrolyte and between the solvent and the solute can be ensured. At the same time, the liquid tension can be reduced, enabling the electrolyte to better infiltrate the inside of the electrode sheet, making the ion shuttle and reaction smoother, with a smaller DCR value of the battery, which is more conducive to improving the cycle reversibility of the battery.

[0022] c) By adding an appropriate amount of antioxidant to the electrolyte for the aqueous battery of the present invention, the volatilization or deterioration of polar organic solvents in the electrolyte can be effectively prevented, ensuring that the concentration of the electrolyte does not deviate significantly during the use of the battery. By adding an appropriate amount of surfactant, the reduction of the ion solvation sheath bond energy can be promoted, the energy loss in ion reaction kinetics can be reduced, and the reversibility of the electrode material and the Coulomb efficiency of the battery can be improved. By adjusting the initial pH of the electrolyte to be around neutral with an acid-base buffer, the purpose is to prevent the occurrence of hydrogen evolution reaction (HER) or oxygen evolution reaction (OER) on the surface of the amphoteric metal current collector during electrochemical characterization. And during the cycling process of the battery, due to the presence of the acid-base buffer and weak acid root salts, the pH of the electrolyte can be adjusted in a timely manner to prevent the corrosion of the amphoteric metal current collector, thereby avoiding the aggravation of side reactions or the damage of the aqueous battery.

[0023] d) The present invention aims to be able to widely apply amphoteric metals in the current collectors of aqueous batteries and slow down or even avoid the corrosion of amphoteric metals in aqueous electrolytes. To a certain extent, the types of current collectors available for aqueous batteries are expanded. The electrolyte of the present invention can enable a more sufficient matching degree between the current collector and the electrolyte, and minimize the impact on the electrochemical performance of the battery caused by changing electrolyte factors, so as to give full play to the electrochemical performance of the aqueous battery and promote the rapid development of aqueous batteries.

[0024] e) The aqueous battery using the electrolyte of the present invention can be adapted to more types of amphoteric metals, thereby effectively alleviating or even avoiding the corrosion of amphoteric metal current collectors and further extending the cycle life of aqueous batteries.

[0025] Other features and advantages of the present invention will be described in the subsequent specification, and some of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the written specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs represent the same components;

[0027] Figure 1 It is a conductivity graph of the electrolytes of Example 1 and Comparative Example 1;

[0028] Figure 2 Conductivity diagram of the electrolytes of Example 2 and Comparative Example 2;

[0029] Figure 3 Comparison diagram of current collectors after cycling of the aqueous sodium battery of Example 1 and Comparative Example 1;

[0030] Figure 4 Comparison diagram of current collectors after cycling of the aqueous lithium battery of Example 2 and Comparative Example 2;

[0031] Figure 5 Percentage of electrolyte concentration after cycling of the aqueous sodium battery of Example 1 and Comparative Example 1 (recorded as 100% before cycling);

[0032] Figure 6 Percentage of electrolyte concentration after cycling of the aqueous lithium battery of Example 2 and Comparative Example 2 (recorded as 100% before cycling);

[0033] Figure 7 DCR diagram of the aqueous sodium battery of Example 1 and Comparative Example 1;

[0034] Figure 8 DCR diagram of the aqueous lithium battery of Example 2 and Comparative Example 2;

[0035] Figure 9 Cycling performance diagram of the aqueous sodium battery of Example 1 and Comparative Example 1;

[0036] Figure 10 Cycling performance diagram of the aqueous lithium battery of Example 2 and Comparative Example 2. Detailed implementation manners

[0037] The following will specifically describe the preferred embodiments of the present invention in conjunction with the accompanying drawings, wherein the accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention.

[0038] The present invention provides an electrolyte for an aqueous battery. The components of the electrolyte for the aqueous battery include: a solvent, an electrolyte salt, an additive, and an acid-base buffer; wherein, the electrolyte salt includes a strong acid root salt and a weak acid root salt, and the additive includes a stabilizer, an antioxidant, and a surfactant.

[0039] Specifically, the solvent can provide a site for the electrochemical reaction and ensure the normal progress of the oxidation-reduction reaction during charge and discharge; specifically, the solvent includes water and an organic solvent.

[0040] Specifically, to prevent impurity contamination, deionized water can be used; the organic solvent can be a polar organic solvent, and the polar organic solvent can be one or more of alcohols, acetonitrile, chloroform, DMSO, pyridine, acetone, formamide, triethylamine, tributylamine, trioctylamine, hexamethylphosphoramide, tetramethylethylenediamine, trifluoroacetic acid, ethyl acetate, dioxane, and tetrahydrofuran. The above polar organic solvents can be miscible with deionized water in a certain proportion, and after the solute is completely dissolved, they can jointly undergo a solvation effect with deionized water. For example, the polar organic solvent can be alcohols and acetonitrile, and the volume ratio of alcohols to acetonitrile is 1 to 2:1; the polar organic solvent can be triethylamine and dioxane, and the volume ratio of triethylamine to dioxane is 1 to 2:1; the polar organic solvent can be DMSO and acetone, and the volume ratio of DMSO to acetone is 2 to 3:1; the polar organic solvent can be pyridine and tetramethylethylenediamine, and the volume ratio of pyridine to tetramethylethylenediamine is 1.5 to 3:1.

[0041] Specifically, considering that too much amount of polar organic solvent is likely to cause too low ionic conductivity of the electrolyte, affecting the rate of electrochemical reaction, while too little amount of organic solvent is likely to cause serious hydrogen evolution / oxygen evolution reaction at high voltage. Therefore, to keep the electrolyte with a high ionic conductivity and provide a reaction site for the strong dynamic movement of ions, the volume ratio of water to polar organic solvent is controlled to be (2 to 20):1, such as 5:1, 8:1, 10:1, 13:1, 15:1, 18:1, and preferably (5 to 15):1.

[0042] Specifically, the electrolyte salt is used to provide the main ions required for the electrochemical reaction. Different electrolyte salts can undergo ionization or hydrolysis after dissolution. The ions ionized therein can play a role in ion transport, while the H - or OH - can adjust the pH of the electrolyte. An appropriate concentration of electrolyte salt can, while ensuring high ionic conductivity, greatly reduce the concentration polarization in the electrochemical reaction.

[0043] Specifically, the above electrolyte salts include strong acid radical salts and weak acid radical salts. Among them, the strong acid radical salt is the main salt of the electrolyte, and the strong acid radical salt can be one or more of sulfate, nitrate, aminosulfonate, trifluoromethylsulfonate, fluoride, chlorate, perchlorate, permanganate, etc.; for example, the strong acid radical salt can be sulfate and perchlorate, and the molar ratio of sulfate to perchlorate is 1-2:4-5; for example, the strong acid radical salt can be nitrate and aminosulfonate; the weak acid radical salt is the secondary salt of the electrolyte, and can be one or more of carbonate salt, bicarbonate salt, acetate salt, sulfite salt, bisulfite salt, phosphate salt, hydrogen phosphate salt, dihydrogen phosphate salt, oxalate salt, silicate salt, etc.; for example, the weak acid radical salt can be dihydrogen phosphate salt and acetate salt, and the molar ratio of dihydrogen phosphate salt to acetate salt is 1-2:2; the weak acid radical salt can be carbonate salt and oxalate salt, and the molar ratio of carbonate salt to oxalate salt is 1-2:3-4; the cation of the electrolyte salt can be Li + , Na + , K + , Mg 2+ , Zn 2+ , Ca 2+ , Al 3+ , Fe 2+ , Fe 3+ , Cu 2+ , Ag + , Pb 2+ , Sn 2+ , NH 4 + , NR 4 + and C 5 H 5 NH + etc., and one of them.

[0044] Specifically, in order to ensure that a relatively large number of ions and relatively high ionic conductivity can be provided, and the normal redox reaction rate can be satisfied, the concentration of the strong acid radical salt in the above electrolyte salt is 0.5-18 mol / L, such as 1 mol / L, 3 mol / L, 5 mol / L, 7 mol / L, 10 mol / L, 13 mol / L, 15 mol / L, and preferably 1-10 mol / L.

[0045] Specifically, in order to effectively balance the ionic concentration of the electrolyte solution and, to a certain extent, adjust the pH value of the electrolyte solution, the concentration of the weak acid radical salt in the electrolyte salt is controlled to be 0.1-6 mol / L, such as 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 3 mol / L, 5 mol / L, and preferably 0.3-4 mol / L.

[0046] Specifically, stabilizers can increase the bond energy between water and organic solvents, slow down the volatilization of organic solvents, thereby ensuring that the concentration of the electrolyte remains unchanged and preventing safety hazards caused by volatilized organic solvents; antioxidants can prevent the electrolyte from deteriorating and extend the service life of the electrolyte; surfactants can improve the solid-liquid interfacial tension, reduce the ion solvation sheath energy, and accelerate the electrochemical reaction rate. Acid-base buffers are used to adjust the final pH of the electrolyte after the electrolyte volume is fixed to meet the battery injection standards, thereby ensuring the battery formation results and subsequent performance.

[0047] Specifically, the stabilizer can be one or more of phosphate, sodium citrate, tartrate, glycine, polyvinyl alcohol, polyacrylic acid, magnesium succinate and sodium dehydrocholate.

[0048] Considering that too much stabilizer is easy to preempt the electrochemical reaction, resulting in aggravation of side reactions; too little stabilizer is easy to cause weak bond energy of solvated molecules, uneven distribution of electrolyte solvent or excessive volatilization of solvent, etc. Therefore, the mass of the stabilizer is controlled to account for 0.01% to 0.1% of the total mass of the electrolyte salt in the electrolyte, such as 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, preferably 0.01 to 0.05%.

[0049] Specifically, the antioxidant can be one or more of ascorbic acid, tea polyphenols, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, tert-butylhydroquinone, citric acid, EDTA, ascorbyl palmitate, and the like.

[0050] Considering that too much antioxidant may cause a reduction reaction of part of the electrolyte salt, resulting in changes in the electrolyte components; too little antioxidant may not guarantee the antioxidant capacity of the electrolyte, which may cause the electrolyte to deteriorate and fail. Therefore, the content of the antioxidant is controlled to account for 0.05% to 1% of the total mass of the electrolyte salt in the electrolyte, such as 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, preferably 0.05% to 0.5%.

[0051] Specifically, the surfactant can be one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, stearic acid, lauric acid, lecithin, alkyl glucoside, sorbitan fatty acid, coconut acid monoethanolamide, coconut acid diethanolamide, fatty alcohol polyoxyethylene ether ammonium sulfate, potassium lauryl ether phosphate and disodium lauryl sulfosuccinate.

[0052] Considering that an excessive amount of surfactant is likely to lead to an increase in interfacial tension, making it difficult for ion / electron exchange; while too little surfactant cannot reduce the ion solvation sheath energy and will lower the Coulombic efficiency of the battery. Therefore, the content of the surfactant is controlled to be 0.01% - 0.5% of the total mass of the electrolyte salt in the electrolyte, such as 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, and preferably 0.02% - 0.3%.

[0053] Specifically, the acid-base buffer can be one or more of ammonia water, acetic acid, oxalic acid, phosphoric acid, boric acid, citric acid, and barbituric acid, etc.

[0054] Specifically, the dosage of the acid-base buffer is determined according to the set pH value of the electrolyte. By adding the buffer dropwise to the electrolyte until pH = 6.9 - 7.1.

[0055] The present invention also provides a preparation method of the electrolyte for the above-mentioned aqueous battery, including the following steps:

[0056] Step 1: Mix water and an organic solvent to obtain a mixed solvent;

[0057] Step 2: Add the electrolyte salt to the mixed solvent and mix to obtain Solution A;

[0058] Step 3: Add the stabilizer, antioxidant, and surfactant to Solution A in sequence and dissolve them completely to obtain Solution B;

[0059] Step 4: Add the acid-base buffer to Solution B and adjust the pH of Solution B to neutral to obtain the electrolyte for the aqueous battery.

[0060] Specifically, in Step 1, stirring can be used to accelerate the mixing process during mixing. If the stirring speed is too high, it is easy to cause splashing of the solution and excessive shear force, resulting in phenomena such as demulsification or stratification of the electrolyte; if it is too low, it will cause too long dissolution time of the solute and uneven components of the electrolyte in all directions. Therefore, in order to ensure that an appropriate shear force can be provided and the solvation bond energy between the polar organic solvent and water is not damaged during the preparation process of the electrolyte, thus avoiding stratification, the stirring speed in Step 1 is controlled to be 50 - 280 r / min, such as 80 r / min, 100 r / min, 150 r / min, 180 r / min, 200 r / min, 250 r / min, and preferably 100 - 250 r / min.

[0061] Specifically, in Step 2, stirring can be used to accelerate the mixing process during mixing, and the stirring speed is 50 - 280 r / min, such as 80 r / min, 100 r / min, 150 r / min, 180 r / min, 200 r / min, 250 r / min, and preferably 100 - 250 r / min.

[0062] Specifically, in step 3, considering the stability of the solvated molecular structure after the electrolyte salt is dissolved, adding a stabilizer first can ensure that the bond energy of the solvated molecules does not break. Secondly, adding an antioxidant can slow down the volatilization and deterioration of the electrolyte. Finally, for the surfactant added last, its molecules can provide efficient interfacial reaction ability for the ions in the electrolyte, improving the electrochemical performance of the battery. Therefore, the stabilizer, antioxidant, and surfactant are added to solution A in sequence.

[0063] The present invention also provides an aqueous battery including the above-mentioned electrolyte for an aqueous battery.

[0064] Specifically, the aqueous battery can be one of an aqueous lithium-ion battery, an aqueous sodium-ion battery, an aqueous potassium-ion battery, an aqueous zinc-ion battery, an aqueous magnesium-ion battery, an aqueous aluminum-ion battery, an aqueous zinc-nickel secondary battery, a supercapacitor, and an aqueous dual-ion battery, etc.

[0065] Specifically, the preparation method of the aqueous battery includes the following steps:

[0066] S1. Select a current collector according to the required assembled aqueous battery, cut it into a suitable size, and clean the surface of the current collector with anhydrous ethanol;

[0067] S2. Assemble the electrode sheets, separator, current collector, etc. required for the aqueous battery into an electrode core and put it into a shell, inject an appropriate amount of the above-mentioned electrolyte, and then seal and stand still to obtain the aqueous battery.

[0068] After formation and grading, the electrochemical performance test of the aqueous battery can be carried out.

[0069] Specifically, the current collector in the above S1 can be one or more of Al foil, Zn foil, Sn foil, Ni foil, foam Ni, Ti foil, Ti mesh, stainless steel foil, stainless steel mesh, foam Fe, carbon cloth, carbon paper, AC paper, and graphite paper, etc. Among them, Al foil, Zn foil, and Sn foil are amphoteric metal current collectors.

[0070] Specifically, in the above S1, the types of current collectors used for the positive and negative electrodes of the aqueous battery can be different. It can be that only the current collector of one electrode is an amphoteric metal, or the current collectors of both the positive and negative electrodes are amphoteric metals.

[0071] Compared with the prior art, the electrolyte salts of the electrolyte for the aqueous battery of the present invention include strong acid radical salts and weak acid radical salts. The main salt of the electrolyte is a strong acid radical salt, which can be completely ionized after being completely dissolved, providing a rich ion concentration for the electrolyte, thereby increasing the ionic conductivity and ion transport rate of the electrolyte, further accelerating the rate of the electrochemical reaction, and to a certain extent, reducing the adverse effects caused by concentration polarization; the secondary salt of the electrolyte is a weak acid radical salt. After being completely dissolved, the weak acid radical can undergo partial hydrolysis. When an amphoteric metal is used as the current collector in the aqueous battery, the weak acid radical hydrated ions formed by the solvation of the weak acid radical make the weak acid radical able to serve as a medium between the current collector and H 2 O, isolating the direct contact between the metal hydrated ions in the electrolyte and the current collector, thereby avoiding the corrosion of the current collector and slowing down the gas evolution behavior of the electrolyte without affecting ion exchange, and prolonging the cycle life of the battery.

[0072] By adding an appropriate amount of stabilizer to the electrolyte for the aqueous battery of the present invention, the balance between solvents in the electrolyte and between the solvent and the solute can be ensured. At the same time, the liquid tension can be reduced, enabling the electrolyte to better infiltrate the inside of the electrode sheet, making ion shuttling and reactions smoother, with a smaller DCR value of the battery, and being more conducive to improving the cycle reversibility of the battery.

[0073] By adding an appropriate amount of antioxidant to the electrolyte for the aqueous battery of the present invention, the volatilization or deterioration of the polar organic solvent in the electrolyte can be effectively prevented, ensuring that the concentration of the electrolyte does not deviate significantly during the use of the battery. By adding an appropriate amount of surfactant, the reduction of the ion solvation sheath bond energy can be promoted, the energy loss in ion reaction kinetics can be reduced, and the reversibility of the electrode material and the Coulomb efficiency of the battery can be improved. By adjusting the initial pH of the electrolyte to be around neutral with an acid-base buffer, the purpose is to prevent the hydrogen evolution reaction (HER) or oxygen evolution reaction (OER) from occurring on the surface of the amphoteric metal current collector during electrochemical characterization. And during the cycle of the battery, due to the presence of the acid-base buffer and the weak acid radical salt, the pH of the electrolyte can be adjusted in a timely manner to prevent the corrosion of the amphoteric metal current collector, thereby avoiding the aggravation of side reactions or the damage of the aqueous battery.

[0074] The present invention aims to be able to widely apply amphoteric metals in the current collectors of aqueous batteries and slow down or even avoid the corrosion of amphoteric metals in aqueous electrolytes, so as to be able to normally carry out the characterization of electrochemical performance. At the same time, to a certain extent, it also expands the types of current collectors that can be used in aqueous batteries. The electrolyte of the present invention can enable the current collector and the electrolyte to have a more sufficient matching degree, and minimize the impact on the electrochemical performance of the battery caused by changing electrolyte factors, so as to give full play to the electrochemical performance of the aqueous battery and promote the rapid development of aqueous batteries.

[0075] The aqueous battery using the electrolyte of the present invention can be adapted to more types of amphoteric metals, thereby effectively alleviating or even avoiding the corrosion of the amphoteric metal current collector and further extending the cycle life of the aqueous battery.

[0076] The technical solution of the present invention will be further explained and illustrated below in conjunction with specific embodiments. It should be noted that the data in the embodiments are all exemplary descriptions, and during the production process, the dosage can be determined according to actual needs.

[0077] Example 1:

[0078] This example provides an electrolyte for an aqueous battery, its preparation method, and an aqueous battery.

[0079] The preparation method of the electrolyte for the aqueous battery in this example includes the following steps:

[0080] 1. Deionized water, isopropanol, and acetonitrile are added to a container in a volume ratio of 9:0.5:0.5, with a total of 20 mL. At room temperature, it is continuously stirred at a rate of 240 r / min to make it fully homogeneous, obtaining a mixed solvent;

[0081] 2. Weigh 6.88 g of sodium trifluoromethanesulfonate as a strong acid root salt and 1.64 g of sodium acetate as a weak acid root salt respectively, and add them to the mixed solvent in sequence. Continue to stir at a rate of 240 r / min until it is completely dissolved, obtaining Solution A;

[0082] 3. Weigh 0.0026 g of sodium dihydrogen phosphate, 0.0213 g of EDTA, and 0.0128 g of sodium dodecyl sulfate respectively, and add them to Solution A in sequence to make it completely dissolved, obtaining Solution B;

[0083] 4. Add an appropriate amount of acetic acid to Solution B and adjust the pH of Solution B to 6.95, that is, the electrolyte prepared in this example is obtained.

[0084] The aqueous battery in this example includes the above-mentioned electrolyte for the aqueous battery. The preparation method of the aqueous battery includes the following steps:

[0085] 5. According to the required assembled aqueous sodium-ion battery, Al foil is used as the current collector for both the positive and negative electrodes, and it is cut into appropriate sizes, and the surface of the current collector is cleaned with absolute ethanol;

[0086] 6. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous sodium-ion battery into a battery core and put it into a shell. After injecting an appropriate amount of the above-mentioned electrolyte, it is sealed and left standing to obtain an aqueous sodium-ion battery.

[0087] After formation and grading, the electrochemical performance test of the aqueous sodium-ion battery can be carried out.

[0088] Example 2:

[0089] This embodiment provides an electrolyte for an aqueous battery, a preparation method thereof, and an aqueous battery.

[0090] The preparation method of the electrolyte for the aqueous battery in this embodiment includes the following steps:

[0091] 1. Add deionized water, triethylamine, and dioxane into a container according to a volume ratio of 14:1:1, with a total of 16 mL. Continuously stir at a rate of 150 r / min at room temperature to make it fully homogeneous, and obtain a mixed solvent.

[0092] 2. Weigh 15.3 g of lithium perchlorate as a strong acid root salt, 1.664 g of lithium dihydrogen phosphate, and 2.112 g of lithium acetate as weak acid root salts respectively, and add them into the mixed solvent in sequence. Continue to stir at a rate of 150 r / min until it is completely dissolved to obtain solution A.

[0093] 3. Weigh 0.0038 g of magnesium succinate, 0.0286 g of ascorbic acid, and 0.0153 g of coconut diethanolamide respectively, and add them into solution A in sequence to make it completely dissolved to obtain solution B.

[0094] 4. Add an appropriate amount of ammonia water into solution B, and adjust the pH of solution B to 7.05, then the electrolyte prepared in this embodiment is obtained.

[0095] The aqueous battery in this embodiment includes the above-mentioned electrolyte for the aqueous battery. The preparation method of the aqueous battery includes the following steps:

[0096] 5. According to the required assembled aqueous lithium-ion battery, use Al foil as the positive current collector and Cu foil as the negative current collector, cut them into appropriate sizes, and clean the surfaces of the current collectors with absolute ethanol.

[0097] 6. Assemble the electrode sheets, separator, current collector, etc. required for the aqueous lithium-ion battery into a battery core and put it into a shell. After injecting an appropriate amount of the above-mentioned electrolyte, seal and let it stand to obtain an aqueous lithium-ion battery.

[0098] After formation and grading, the electrochemical performance test of the aqueous lithium-ion battery can be carried out.

[0099] Example 3:

[0100] This embodiment provides an electrolyte for an aqueous battery, a preparation method thereof, and an aqueous battery.

[0101] The preparation method of the electrolyte for the aqueous battery in this embodiment includes the following steps:

[0102] 1. Add deionized water, DMSO, and acetone into a container in a volume ratio of 24:1.5:0.5, with a total of 26 mL. Continuously stir at a rate of 180 r / min at room temperature to make it fully homogeneous, obtaining a mixed solvent;

[0103] 2. Weigh 6.29 g of zinc sulfate and 27.2 g of zinc perchlorate as strong acid root salts, and 1.09 g of sodium bicarbonate and 4.04 g of zinc dihydrogen phosphate as weak acid root salts respectively, and add them into the mixed solvent in sequence. Continue to stir at a rate of 180 r / min until they are completely dissolved, obtaining solution A;

[0104] 3. Weigh 0.0155 g of sodium tartrate, 0.1352 g of dibutylhydroxytoluene, and 0.0966 g of alkyl glucoside respectively, and add them into solution A in sequence to make them completely dissolved, obtaining solution B;

[0105] 4. Add an appropriate amount of ammonia water into solution B and adjust the pH of solution B to 7, then the electrolyte solution prepared in this example is obtained.

[0106] The aqueous battery of this example includes the above-mentioned electrolyte solution for the aqueous battery. The preparation method of the aqueous battery includes the following steps:

[0107] 5. According to the required assembled aqueous zinc ion battery, use a Ti mesh as the positive electrode current collector and a Zn foil as the negative electrode current collector, cut them into appropriate sizes, and clean the surfaces of the current collectors with absolute ethanol;

[0108] 6. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous zinc ion battery into an electric core and put it into a shell. Inject an appropriate amount of the above-mentioned electrolyte solution and then seal and let it stand to obtain the aqueous zinc ion battery.

[0109] After formation and grading, the electrochemical performance test of the aqueous zinc ion battery can be carried out.

[0110] Example 4:

[0111] This example provides an electrolyte solution for an aqueous battery, its preparation method, and an aqueous battery.

[0112] The preparation method of the electrolyte solution for the aqueous battery in this example includes the following steps:

[0113] 1. Add deionized water, pyridine, and tetramethylethylenediamine into a container in a volume ratio of 30:6:4, with a total of 40 mL. Continuously stir at a rate of 170 r / min at room temperature to make it fully homogeneous, obtaining a mixed solvent;

[0114] 2. Weigh 6.8 g of sodium nitrate and 9.52 g of sodium aminosulfonate as strong acid root salts, and 8.52 g of disodium hydrogen phosphate and 2.68 g of sodium oxalate as weak acid root salts respectively, and add them to the mixed solvent in sequence. Then continue to stir at a rate of 170 r / min until they are completely dissolved to obtain solution A;

[0115] 3. Weigh 0.0028 g of sodium citrate, 0.0137 g of tea polyphenols and 0.0083 g of sodium dodecylbenzenesulfonate respectively, and add them to solution A in sequence until they are completely dissolved to obtain solution B;

[0116] 4. Add an appropriate amount of phosphoric acid to solution B and adjust the pH of solution B to 7.0, then the electrolyte prepared in this example is obtained.

[0117] The aqueous battery of this example includes the above-mentioned electrolyte for aqueous battery. The preparation method of the aqueous battery includes the following steps:

[0118] 5. According to the required assembled aqueous sodium-ion battery, Al foil is used as the current collector for both the positive and negative electrodes, and it is cut into appropriate sizes, and the surface of the current collector is cleaned with anhydrous ethanol;

[0119] 6. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous sodium-ion battery into a battery core and put it into a shell. After injecting an appropriate amount of the above-mentioned electrolyte, seal it and let it stand to obtain the aqueous sodium-ion battery.

[0120] After formation and grading, the electrochemical performance test of the aqueous sodium-ion battery can be carried out.

[0121] Example Five:

[0122] This example provides an electrolyte for an aqueous battery, its preparation method and an aqueous battery.

[0123] The preparation method of the electrolyte for the aqueous battery of this example includes the following steps:

[0124] 1. Add deionized water, formamide and hexamethylphosphoramide to a container according to a volume ratio of 18:2:1, with a total of 21 mL. Stir continuously at a rate of 130 r / min at room temperature until they are fully homogenized to obtain a mixed solvent;

[0125] 2. Weigh 3.32 g of sodium permanganate as a strong acid root salt and 6.89 g of sodium acetate and 2.23 g of sodium carbonate as weak acid root salts respectively, and add them to the mixed solvent in sequence. Then continue to stir at a rate of 130 r / min until they are completely dissolved to obtain solution A;

[0126] 3. Weigh 0.0075 g of sodium dehydrocholate, 0.0249 g of tert-butylhydroquinone, and 0.0062 g of disodium lauryl sulfosuccinate respectively, and add them to solution A in sequence to completely dissolve them, obtaining solution B;

[0127] 4. Add an appropriate amount of barbituric acid to solution B and adjust the pH of solution B to 6.95, then the electrolyte solution prepared in this example is obtained.

[0128] The aqueous battery of this example includes the above-mentioned electrolyte solution for the aqueous battery. The preparation method of the aqueous battery includes the following steps:

[0129] 5. According to the required assembled aqueous sodium-ion battery, Al foil is used as the current collector for both the positive and negative electrodes, cut into appropriate sizes, and the surface of the current collector is cleaned with absolute ethanol;

[0130] 6. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous sodium-ion battery into an electric core, put it into a shell, inject an appropriate amount of the above-mentioned electrolyte solution, and then seal and let it stand to obtain the aqueous sodium-ion battery.

[0131] After formation and grading, the electrochemical performance test of the aqueous sodium-ion battery can be carried out.

[0132] Example Six:

[0133] This example provides an electrolyte solution for an aqueous battery, its preparation method, and an aqueous battery.

[0134] The preparation method of the electrolyte solution for the aqueous battery in this example includes the following steps:

[0135] 1. Add deionized water, ethanol, and ethyl acetate to a container according to a volume ratio of 30:0.5:1.5, with a total of 32 mL, and continuously stir at a rate of 210 r / min at room temperature to make it fully homogeneous, obtaining a mixed solvent;

[0136] 2. Weigh 40.7 g of lithium perchlorate, 6.6 g of lithium amidosulfonate as strong acid root salts, 6.33 g of lithium acetate, and 3.68 g of lithium phosphate as weak acid root salts respectively, and add them to the mixed solvent in sequence, and continue to stir at a rate of 210 r / min to completely dissolve them, obtaining solution A;

[0137] 3. Weigh 0.043 g of polyvinyl alcohol, 0.172 g of ascorbyl palmitate, and 0.1146 g of coconut monoethanolamide respectively, and add them to solution A in sequence to completely dissolve them, obtaining solution B;

[0138] 4. Add an appropriate amount of ammonia water to solution B and adjust the pH of solution B to 7.05, then the electrolyte solution prepared in this example is obtained.

[0139] The aqueous battery of this embodiment includes the above-mentioned electrolyte for aqueous batteries. The preparation method of the aqueous battery includes the following steps:

[0140] 5. For the assembled aqueous lithium-ion battery as required, use Al foil as the positive current collector and Cu foil as the negative current collector, cut them into appropriate sizes, and clean the surfaces of the current collectors with absolute ethanol.

[0141] 6. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous lithium-ion battery into an electrode core, put it into a shell, inject an appropriate amount of the above-mentioned electrolyte, and then seal and let it stand still to obtain the aqueous lithium-ion battery.

[0142] After formation and grading, the electrochemical performance test of the aqueous lithium-ion battery can be carried out.

[0143] Example Seven:

[0144] This embodiment provides an electrolyte for aqueous batteries, its preparation method, and an aqueous battery.

[0145] The preparation method of the electrolyte for the aqueous battery of this embodiment includes the following steps:

[0146] 1. Add deionized water, glycerol, and dioxane into a container according to a volume ratio of 18:0.5:0.5, with a total of 19 mL. Continuously stir at a rate of 110 r / min at room temperature to make it fully homogeneous to obtain a mixed solvent.

[0147] 2. Weigh 1.16 g of lithium perchlorate as the strong acid root salt, 0.36 g of lithium sulfite, and 0.78 g of lithium hydrogen phosphate as the weak acid root salts respectively, and add them to the mixed solvent in sequence. Continue to stir at a rate of 110 r / min until they are completely dissolved to obtain Solution A.

[0148] 3. Weigh 0.0021 g of polyacrylic acid, 0.0104 g of citric acid, and 0.0092 g of lecithin respectively, and add them to Solution A in sequence to make them completely dissolved to obtain Solution B.

[0149] 4. Add an appropriate amount of ammonia water to Solution B and adjust the pH of Solution B to 6.95 to obtain the electrolyte prepared in this embodiment.

[0150] The aqueous battery of this embodiment includes the above-mentioned electrolyte for aqueous batteries. The preparation method of the aqueous battery includes the following steps:

[0151] 5. For the assembled aqueous lithium-ion battery as required, use Al foil as the positive current collector and Cu foil as the negative current collector, cut them into appropriate sizes, and clean the surfaces of the current collectors with absolute ethanol.

[0152] 6. Assemble the electrode sheets, separator, current collector, etc. required for the aqueous lithium-ion battery into a battery cell, put it into a casing, inject an appropriate amount of the above-mentioned electrolyte solution, and then seal and let it stand to obtain the aqueous lithium-ion battery.

[0153] After formation and grading, the electrochemical performance test of the aqueous lithium-ion battery can be carried out.

[0154] Comparative Example 1:

[0155] This comparative example provides an electrolyte solution, its preparation method and an aqueous battery.

[0156] The electrolyte salt in this comparative example does not contain weak acid root salts. The preparation method of the electrolyte solution includes the following steps:

[0157] 1. Add deionized water, isopropanol, and acetonitrile to a container according to a volume ratio of 9:0.5:0.5, with a total of 20 mL. Stir continuously at a rate of 240 r / min at room temperature to make it fully homogeneous to obtain a mixed solvent;

[0158] 2. Weigh 6.88 g of sodium trifluoromethanesulfonate as a strong acid root salt and add it to the mixed solvent. Continue to stir at a rate of 240 r / min until it is completely dissolved to obtain Solution A;

[0159] 3. Weigh 0.0026 g of sodium dihydrogen phosphate, 0.0213 g of EDTA, and 0.0128 g of sodium dodecyl sulfate respectively, and add them to Solution A in sequence to make them completely dissolved to obtain Solution B;

[0160] 4. Add an appropriate amount of ammonia water to Solution B and adjust the pH of Solution B to 6.95 to obtain the electrolyte solution;

[0161] 5. According to the required assembled aqueous sodium-ion battery, Al foil is used as the current collector for both the positive and negative electrodes, cut into appropriate sizes, and the surface of the current collector is cleaned with anhydrous ethanol;

[0162] 6. Assemble the electrode sheets, separator, current collector, etc. required for the aqueous sodium-ion battery into a battery cell, put it into a casing, inject an appropriate amount of the above-mentioned electrolyte solution, and then seal and let it stand;

[0163] 7. After formation and grading, the electrochemical performance test of the aqueous sodium-ion battery can be carried out.

[0164] Comparative Example 2:

[0165] This comparative example provides an electrolyte solution, its preparation method and an aqueous battery.

[0166] The electrolyte solution in this comparative example does not contain additives. The remaining steps of the preparation method of the electrolyte solution are the same as those in Example 2 and will not be elaborated here.

[0167] According to the required assembled aqueous lithium-ion battery, Al foil is used as the current collector for the positive electrode and Cu foil is used as the current collector for the negative electrode, which are cut into appropriate sizes, and the surfaces of the current collectors are cleaned with absolute ethanol; the electrode sheets, separators, current collectors, etc. required for the aqueous lithium-ion battery are assembled into a battery cell and put into a case, and after injecting an appropriate amount of the above electrolyte, it is sealed and left standing; after formation and grading, the electrochemical performance test of the aqueous lithium-ion battery can be carried out.

[0168] Comparative Example 3:

[0169] This comparative example provides an electrolyte, its preparation method and an aqueous battery.

[0170] The electrolyte in this comparative example does not contain weak acid salts and additives. The preparation method of the electrolyte includes the following steps:

[0171] 1. Add deionized water, DMSO, and acetone into a container according to a volume ratio of 24:1.5:0.5, with a total of 26 mL, and continuously stir at a rate of 180 r / min at room temperature to make it fully homogeneous, obtaining a mixed solvent;

[0172] 2. Weigh 6.29 g of zinc sulfate and 27.2 g of zinc perchlorate as strong acid salts respectively, add them into the mixed solvent, and continue to stir at a rate of 180 r / min until they are completely dissolved, obtaining Solution A;

[0173] 3. Add an appropriate amount of ammonia water to Solution A and adjust the pH of Solution A to 7, then the electrolyte prepared in the present invention is obtained;

[0174] 4. According to the required assembled aqueous zinc-ion battery, Ti mesh is used as the current collector for the positive electrode and Zn foil is used as the current collector for the negative electrode, which are cut into appropriate sizes, and the surfaces of the current collectors are cleaned with absolute ethanol;

[0175] 5. Assemble the electrode sheets, separators, current collectors, etc. required for the aqueous zinc-ion battery into a battery cell and put it into a case, inject an appropriate amount of the above electrolyte, and then seal and leave it standing;

[0176] 6. After formation and grading, the electrochemical performance test of the aqueous zinc-ion battery can be carried out.

[0177] The performance tests of the examples and comparative examples are shown in Table 1 below. It can be seen that the voltage window of the electrolyte of the present invention is widened. For example, the voltage window of the electrolyte is above 2.5 V, such as 2.55 - 2.8 V; the corrosion potential of the current collector is increased, indicating that the current collector is more corrosion-resistant in the electrolyte of the present invention; during the cycling process of the electrolyte provided by the present invention, the volatilization of the solvent in the electrolyte can be effectively alleviated, and the physicochemical properties of the electrolyte are ensured to remain unchanged to the greatest extent. For example, the solute concentration of the electrolyte after cycling is 102% - 111%, providing a good site for the electrochemical reaction. The DCR of the aqueous battery of the present invention is low. For example, the DCR is 15 - 27 mΩ; the discharge specific capacity of the aqueous battery of the present invention is increased. For example, the discharge specific capacity reaches above 70 mAh / g, such as 70 - 340 mAh / g; the cycle life is extended. For example, the cycle life reaches above 240 cycles.

[0178] Table 1 Performance test results of examples and comparative examples

[0179]

[0180] Figure 1 It is the conductivity graph of the electrolytes of Example 1 and Comparative Example 1. Figure 2 It is the conductivity graph of the electrolytes of Example 2 and Comparative Example 2; it can be seen that compared with the comparative examples, the conductivity of the electrolyte of the present invention does not differ much, indicating that the addition of polar organic solvents can effectively increase the voltage window of the electrolyte without affecting the conductivity.

[0181] Figure 3 It is the comparison graph of the current collectors of the aqueous sodium batteries of Example 1 and Comparative Example 1 after cycling. Figure 4 It is the comparison graph of the current collectors of the aqueous lithium batteries of Example 2 and Comparative Example 2 after cycling; it can be seen that the electrolyte provided by the present invention can effectively alleviate the corrosion of the current collector during the cycling process, greatly extending the cycle life of the aqueous battery.

[0182] Figure 5 It is the percentage of the electrolyte concentration of the aqueous sodium battery of Example 1 and Comparative Example 1 after cycling (the concentration before cycling is recorded as 100%). Figure 6 It is the percentage of the electrolyte concentration of the aqueous lithium battery of Example 2 and Comparative Example 2 after cycling (the concentration before cycling is recorded as 100%); it can be seen that during the cycling process of the electrolyte provided by the present invention, the volatilization of the solvent in the electrolyte can be effectively alleviated, and the physicochemical properties of the electrolyte are ensured to remain unchanged to the greatest extent, providing a good site for the electrochemical reaction.

[0183] Figure 7 It is the DCR graph of the aqueous sodium battery of Example 1 and Comparative Example 1. Figure 8DCR diagram of the aqueous lithium battery of Example 2 and Comparative Example 2; it can be seen that the electrolyte provided by the present invention effectively alleviates the corrosion of the current collector during the cycle, so the DCR of the battery is reduced compared with the comparative example, greatly reducing the ohmic polarization of the battery.

[0184] Figure 9 Cycling performance diagram of the aqueous sodium battery of Example 1 and Comparative Example 1; Figure 10 Cycling performance diagram of the aqueous lithium battery of Example 2 and Comparative Example 2; it can be seen that the electrolyte provided by the present invention can alleviate the problem of current collector corrosion and improve the volatility of the electrolyte, thus effectively extending the cycle life of the aqueous battery.

[0185] It should be noted that when the electrolyte for the aqueous battery of the present invention uses polar organic solvents, electrolyte salts, additives, and acid-base buffers not mentioned in the above embodiments, it can also be applicable to various current collectors, which will not be elaborated here one by one.

[0186] The above are only the preferred specific embodiments 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 those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. An aqueous battery, characterized in that: The aqueous battery includes an aqueous battery electrolyte, and the components of the aqueous battery electrolyte include: a solvent, an electrolyte salt, an additive, and an acid-base buffer; wherein the electrolyte salt includes a strong acid salt and a weak acid salt, and the additive includes a stabilizer, an antioxidant, and a surfactant; The stabilizer is one or more of phosphate, sodium citrate, tartrate, glycinate, polyvinyl alcohol, polyacrylic acid, magnesium succinate and sodium dehydrocholate; The antioxidant is one or more of tea polyphenols, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, tert-butylhydroquinone, citric acid, EDTA, and ascorbyl palmitate; The surfactant can promote the reduction of ion solvation sheath bond energy and reduce energy loss in ion reaction kinetics; The content of surfactant is controlled to be 0.01%~0.5% of the total mass of electrolyte salt in the electrolyte; The mass of the stabilizer is controlled to be 0.01%~0.1% of the total mass of the electrolyte salt in the electrolyte; The aqueous battery is adaptable to amphoteric metal current collectors.

2. The aqueous battery according to claim 1, characterized in that: The solvent includes water and an organic solvent.

3. The aqueous battery according to claim 1, characterized in that: The strong acid salt is one or more of sulfate, nitrate, sulfamate, trifluoromethylsulfonate, fluoride, chlorate, perchlorate and permanganate.

4. The aqueous battery according to claim 1, characterized in that: The weak acid salt is one or more of carbonate, bicarbonate, acetate, sulfite, bisulfite, phosphate, hydrogen phosphate, dihydrogen phosphate, oxalate and silicate.

5. The aqueous battery according to claim 1, characterized in that: The concentration of the strong acid salt is 0.5-18 mol / L.

6. The aqueous battery according to claim 5, characterized in that: The concentration of the weak acid salt is 0.1-6 mol / L.

7. The aqueous battery according to any one of claims 1 to 6, characterized in that: The method for preparing the aqueous battery electrolyte comprises: Step 1, mixing water and an organic solvent to obtain a mixed solvent; Step 2, adding electrolyte salt into the mixed solvent and mixing to obtain solution A; Step 3, adding a stabilizer, an antioxidant and a surfactant to solution A in sequence and mixing them to obtain solution B; Step 4: Add an acid-base buffer to solution B and adjust the pH of solution B to neutral to obtain an electrolyte for an aqueous battery.

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