Amphiphilic hydrogel electrolyte and preparation method, aqueous zinc-manganese battery

Abstract

The application discloses an amphiphilic hydrogel electrolyte and a preparation method and a water-based zinc-manganese battery. The method comprises the following steps: providing a surfactant and an initial electrolyte solution; the electrolyte salt solution is a mixed solution of an electrolyte zinc salt and an electrolyte manganese salt; the surfactant is dissolved in the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant; hydrophobic polymer chain monomers, hydrophilic polymer chain monomers and initiators are sequentially dissolved in the electrolyte salt solution containing the surfactant, and after heating treatment, an amphiphilic hydrogel electrolyte is obtained. The above method only uses the surfactant as a physical crosslinking agent, so that the prepared amphiphilic hydrogel electrolyte has the characteristics of segment dynamic movement, can well control ion transport and optimize electrochemical performance. Moreover, the preparation is achieved by a one-pot method, and the method has the advantages of precise control of the state of the polymer, high repeatability, accurate control of ion concentration, adjustable ion state, and improved electrochemical performance of the electrolyte.

Description

Technical Field

[0001] This application relates to the field of aqueous zinc-manganese battery technology, specifically to an amphiphilic hydrogel electrolyte and its preparation method, and an aqueous zinc-manganese battery. Background Technology

[0002] To address global energy and environmental challenges, "carbon neutrality" has become a global consensus. Clean energy, especially electricity, is gradually replacing traditional fossil fuels, driving the rapid development of energy storage technologies such as lithium-ion batteries (LIBs). However, the organic electrolytes used in LIBs are flammable and toxic, posing safety risks, and the scarcity of lithium resources leads to high costs. Therefore, aqueous battery systems, with their safety and cost advantages, are expected to become an important supplement in the energy storage field. Among them, aqueous zinc-manganese batteries are an excellent choice for energy storage. On the one hand, they use water-based electrolytes, fundamentally solving the safety hazards of traditional lithium batteries, making them less flammable and explosive, and environmentally friendly. On the other hand, zinc and manganese are abundant in the Earth's crust and inexpensive, which can significantly reduce the overall cost of energy storage systems. In addition, this battery system has a high theoretical discharge platform and high theoretical capacity, and its manufacturing process is relatively simple and easy to recycle and reuse, making it very suitable for large-scale application in the field of energy storage.

[0003] However, aqueous zinc-manganese batteries have a relatively low average discharge plateau (<1.5 V vs Zn). 2+ / Zn), which is difficult to widely apply, although it can enable aqueous zinc-manganese batteries to achieve a high theoretical discharge plateau (1.99 V vs Zn) under strongly acidic conditions. 2+ (Zn), however, the strong acidity inevitably corrodes the metallic zinc anode and causes a severe hydrogen evolution reaction, preventing the battery from being used and stored for long periods. Simultaneously, over-discharge leads to battery performance degradation, and current aqueous zinc-manganese batteries lack over-discharge protection mechanisms. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides an amphiphilic hydrogel electrolyte and its preparation method, as well as a technical solution for an aqueous zinc-manganese battery, as described below: On one hand, embodiments of this application provide a method for preparing an amphiphilic hydrogel electrolyte, the preparation method comprising: The solution provides a surfactant, an initial electrolyte solution, a hydrophobic polymer chain monomer, a hydrophilic polymer chain monomer, and an initiator; the electrolyte salt solution is a mixed solution of an electrolyte zinc salt and an electrolyte manganese salt. The surfactant is dissolved in the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant; The hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, and the initiator are dissolved sequentially in the electrolyte salt solution containing the surfactant, and then heated to obtain an amphiphilic hydrogel electrolyte.

[0005] In one possible implementation, the method further includes: The initial electrolyte salt solution is prepared by dissolving the zinc electrolyte salt and the manganese electrolyte salt in water; The initial electrolyte salt solution satisfies at least one of the following characteristics: The volume concentration of the electrolyte salt solution is 1 mol / kg. 水 -2mol / kg 水 ; In the initial electrolyte salt solution, the molar ratio of the zinc electrolyte salt to the manganese electrolyte salt is 1:(0.1-0.6).

[0006] In one possible implementation, the molar ratio of the hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, the surfactant, and the initiator is (0.05-0.15):(2.0-4.0):(0.01-0.06):(0.01-0.06).

[0007] In one possible implementation, the electrolyte zinc salt includes any one or more of zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)imine zinc, and bis(pentafluoroethylsulfonyl)imine zinc; The electrolyte manganese salt includes any one or more of manganese sulfate, manganese chloride, manganese acetate, manganese trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)iminomanganese, and bis(pentafluoroethylsulfonyl)iminomanganese.

[0008] In one possible implementation, the hydrophilic polymer chain monomer includes any one of polyacrylamide, waterborne polyurethane, polymethyl methacrylate sulfonate betaine, polyvinylpyrrolidone, and polyN-isopropylacrylamide.

[0009] In one possible implementation, the hydrophobic polymer chain monomer includes any one of butyl methacrylate, lauryl methacrylate, octadecyl methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoroisopropyl acrylate, and dodecafluoroheptyl methacrylate.

[0010] In one possible implementation, the surfactant comprises any one of bis(octadecyldimethylammonium chloride), hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium α-alkenylsulfonate.

[0011] In one possible implementation, the initiator is ammonium persulfate.

[0012] On the other hand, embodiments of this application also provide an amphiphilic hydrogel electrolyte, which is prepared by the above-described method for preparing amphiphilic hydrogel electrolyte; the amphiphilic hydrogel electrolyte includes electrolyte zinc salt, electrolyte manganese salt, hydrophobic polymer chain monomer, hydrophilic polymer chain monomer and water.

[0013] On the other hand, this application also provides an aqueous zinc-manganese battery, including the above-mentioned amphiphilic hydrogel electrolyte or the amphiphilic hydrogel electrolyte prepared by the above-mentioned preparation method, a positive electrode, and a negative electrode. The positive electrode is made of zinc foil. The negative electrode is made of manganese oxide, which includes at least one of manganese dioxide, lithium manganate, manganese oxide, manganese trioxide, manganese heptaoxide, and potassium manganate.

[0014] The amphiphilic hydrogel electrolyte and its preparation method, as well as the aqueous zinc-manganese battery provided in this application, have the following technical effects: This application discloses an amphiphilic hydrogel electrolyte and its preparation method, as well as an aqueous zinc-manganese battery. The method includes providing a surfactant and an initial electrolyte solution; the electrolyte salt solution is a mixed solution of zinc and manganese electrolytes; the surfactant is dissolved in the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant; hydrophobic polymer monomers, hydrophilic polymer monomers, and an initiator are sequentially dissolved in the electrolyte salt solution containing the surfactant, followed by heat treatment to obtain the amphiphilic hydrogel electrolyte. This method uses only the surfactant as a physical crosslinking agent, enabling the prepared amphiphilic hydrogel electrolyte to possess the characteristics of dynamic chain movement, allowing for excellent control of ion transport and optimized electrochemical performance. Furthermore, the one-pot preparation method offers advantages such as precise control of polymer states, high reproducibility, accurate ion concentration control, and adjustable ion states, thus improving the electrochemical performance of the electrolyte. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of a method for preparing an amphiphilic hydrogel electrolyte provided in an embodiment of this application.

[0017] Figure 2This is a schematic diagram illustrating the mechanism of the preparation process of an amphiphilic hydrogel electrolyte provided in the embodiments of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that, in the description of this application, the following definitions shall apply unless a different definition is given elsewhere in the claims or this specification. All numerical values, whether or not explicitly indicated, are defined herein as being modified by the term "about". The term "about" generally refers to a range of numerical values ​​that a person skilled in the art would consider equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A range of numerical values ​​indicated by a low value and a high value is defined as including all numerical values ​​within that range and all subranges included within that range.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0021] On the one hand, such as Figure 1 As shown in the embodiments of this application, a method for preparing an amphiphilic hydrogel electrolyte is provided, the preparation method comprising: S1: Provides a surfactant, an initial electrolyte solution, a hydrophobic polymer chain monomer, a hydrophilic polymer chain monomer, and an initiator; the electrolyte salt solution is a mixed solution of zinc electrolyte salt and manganese electrolyte salt; S3: Dissolve the surfactant in the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant; S5: The hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, and the initiator are dissolved in the electrolyte salt solution containing the surfactant in sequence, and then heated to obtain an amphiphilic hydrogel electrolyte.

[0022] In this embodiment, the initial electrolyte solution is a mixed aqueous solution of zinc and manganese electrolytes. The surfactant acts as a physical crosslinking agent in the preparation of the amphiphilic hydrogel electrolyte. Hydrophobic polymer chain monomers are polymerizable monomers with hydrophobic groups introduced into their molecular structure, used to impart hydrophobicity, water resistance, or special interfacial properties to the final polymer material. Hydrophilic polymer chain monomers are polymerizable monomers containing hydrophilic groups in their molecular structure, capable of forming hydrogen bonds or undergoing solvation with water molecules, thus endowing polymer materials with properties such as water absorption, water solubility, and biocompatibility. The initiator is a key component initiating the polymerization reaction.

[0023] Specifically, an amphiphilic hydrogel electrolyte is prepared using a one-pot method. First, the surfactant is dissolved in an initial electrolyte salt solution and thoroughly mixed to obtain an electrolyte salt solution containing the surfactant. Then, hydrophobic polymer monomers, hydrophilic polymer monomers, and an initiator are sequentially dissolved in the surfactant-containing electrolyte salt solution, thoroughly mixed, and then heated to obtain the amphiphilic hydrogel electrolyte. In the above process, the raw material addition steps must be strictly followed. First, the surfactant is dissolved in the initial electrolyte solution, forming an electrolyte salt solution containing the surfactant with a stable micelle environment. Then, the hydrophobic polymer monomers, hydrophilic polymer monomers, and initiator are dissolved to constitute the reaction microenvironment. Failure to follow these steps may result in the separation of hydrophilic and hydrophobic materials, or incomplete reaction.

[0024] Optionally, the heat treatment can be a sealed heat treatment, with a heating temperature of 60℃-80℃ and a reaction time of 0.5h-3h. Preferably, it is a sealed heating at 70℃ for 1h.

[0025] In step S3 above, introducing zinc and manganese electrolytes in advance during the synthesis of amphiphilic hydrogel electrolytes can reduce the critical micelle concentration and make the micelles uniformly dispersed in the precursor solution, thereby helping to synthesize a uniform gel electrolyte.

[0026] In step S5 above, such as Figure 2 As shown, the amphiphilic hydrogel electrolyte is formed by integrating hydrophilic polymer chain monomers and hydrophobic polymer chain monomers together through the physical cross-linking center of surfactant. Therefore, the formed gel electrolyte contains a large number of cross-entangled micelles, which make it uniformly hydrated with water molecules.

[0027] Optionally, during the process of adding raw materials, methods such as stirring, ultrasound, or manual stirring can be used to assist in the dissolution of the raw materials, as long as they can be dissolved into a uniform and transparent state without layering or emulsification. This application does not impose specific limitations on this.

[0028] The preparation method of the amphiphilic hydrogel electrolyte provided in this application does not require the use of chemical crosslinking agents, but only uses surfactants as physical crosslinking agents. Compared with methods based on chemical crosslinking agents, the amphiphilic hydrogel electrolyte based on physical crosslinking points in this application has the characteristic of dynamic chain segment movement, which can effectively regulate ion transport and achieve good electrochemical performance. In addition, this synthesis uses a one-pot method to prepare the amphiphilic hydrogel electrolyte, which has the characteristics of precise control of the state of polymer molecules and high reproducibility. Compared with amphiphilic hydrogel electrolytes prepared by preparing a gel and then placing it in a mixed salt solution, the one-pot method can also precisely control the ion concentration and promote the interaction between ions and polymer chains, thereby achieving regulation of the ion state in the electrolyte and thus achieving good electrochemical performance.

[0029] Furthermore, the amphiphilic hydrogel electrolyte prepared in this application embodiment possesses both hydrophilic and hydrophobic units. In practical applications, based on the regulation of the hydrophobic units in the amphiphilic hydrogel electrolyte, the interaction between the hydrophilic functional groups in the gel and water molecules can be enhanced under neutral conditions, thereby broadening the electrochemical stability window of the amphiphilic hydrogel electrolyte. When applied to aqueous zinc-manganese batteries, it can be activated by high-voltage scanning technology, thus enabling the aqueous zinc-manganese battery to have a high theoretical discharge platform. At the same time, the special gel polymer chain structure can promote the oxygen reduction reaction with 2 electron transfer on the zinc negative electrode surface in the aqueous zinc-manganese battery, and realize the self-oxidation reaction of manganese dioxide on the positive electrode side, thereby providing additional discharge capacity to achieve an over-discharge protection mechanism for the aqueous zinc-manganese battery.

[0030] As an optional implementation, the molar ratio of the hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, the surfactant, and the initiator is (0.05-0.15):(2.0-4.0):(0.01-0.06):(0.01-0.06).

[0031] In the embodiments of this application, the amount of surfactant used in the preparation of the amphiphilic hydrogel electrolyte is very small, which is a trace addition. This not only reduces costs, but also ensures that the trace surfactant fully participates in the reaction during the synthesis of the gel electrolyte and is uniformly distributed in the polymer network. This allows for precise control of the ionic behavior in the electrolyte. If the amount of surfactant is increased, the surfactant will not be able to fully participate in the network construction of the gel electrolyte, which will not only be wasteful but also cause the surfactant to be scattered in the gel electrolyte, affecting the movement state of ions in the electrolyte. The ions in the electrolyte will be affected by the surfactants in various places, thus preventing the electrochemical performance from being fully realized.

[0032] As an optional implementation, the method further includes: The initial electrolyte salt solution is prepared by dissolving the zinc electrolyte salt and the manganese electrolyte salt in water; The initial electrolyte salt solution satisfies at least one of the following characteristics: the volume concentration of the electrolyte salt solution is 1 mol / kg water to 2 mol / kg water; and the molar ratio of the zinc electrolyte salt to the manganese electrolyte salt in the initial electrolyte salt solution is 1:(0.1-0.6).

[0033] In this embodiment, the initial electrolyte salt solution is prepared by dissolving zinc and manganese electrolyte salts in water. The initial electrolyte salt solution can also be referred to as a mixed electrolyte salt solution, and the volume concentration of the mixed electrolyte salt solution is 1 mol / kg. 水 -2mol / kg 水 Furthermore, in the initial electrolyte salt solution, the molar ratio of zinc salt and manganese salt is 1:(0.1-0.6).

[0034] As an optional implementation, the electrolyte zinc salt includes any one or more of zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)imine zinc, and bis(pentafluoroethylsulfonyl)imine zinc; The electrolyte manganese salt includes any one or more of manganese sulfate, manganese chloride, manganese acetate, manganese trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)iminomanganese, and bis(pentafluoroethylsulfonyl)iminomanganese.

[0035] As an optional implementation, the hydrophilic polymer chain monomer includes any one of polyacrylamide, waterborne polyurethane, polymethyl methacrylate sulfonate betaine, polyvinylpyrrolidone, and polyN-isopropylacrylamide.

[0036] As an optional implementation, the hydrophobic polymer chain monomer includes any one of butyl methacrylate, lauryl methacrylate, octadecyl methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoroisopropyl acrylate, and dodecafluoroheptyl methacrylate.

[0037] As an optional implementation, the surfactant includes any one of bis(octadecyldimethylammonium chloride), hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium α-alkenylsulfonate.

[0038] As an optional implementation, the initiator is ammonium persulfate.

[0039] In the embodiments of this application, the selection of the above-mentioned surfactant material can be adapted to the affinity and hydrophobic polymer chain monomers of different systems, thereby enabling the customized synthesis of amphiphilic hydrogel electrolytes according to actual application needs and achieving the target electrochemical performance.

[0040] On the other hand, this application embodiment also provides an amphiphilic hydrogel electrolyte, which is prepared by the above-described method for preparing amphiphilic hydrogel electrolyte, and the amphiphilic hydrogel electrolyte includes electrolyte zinc salt, electrolyte manganese salt, hydrophobic polymer chain monomer, hydrophilic polymer chain monomer and water.

[0041] In the embodiments of this application, the hydrophobic segments of the hydrophobic polymer chains in the amphiphilic gel electrolyte can enhance the interaction between the adjacent hydrophilic functional groups in the amphiphilic gel electrolyte and water molecules, thereby broadening the electrochemical stability window of the amphiphilic hydrogel electrolyte so as to activate and stabilize the average high discharge platform of the aqueous zinc-manganese battery using high-voltage scanning technology.

[0042] In this embodiment of the invention, the hydrophobic segments of the hydrophobic polymer chains in the amphiphilic hydrogel electrolyte can undergo hydrophobic association interactions with the hydrophobic regions of the contacting objects, thereby complexing with them and forming a special environment at the interface. Under the action of an electric field, this promotes the redox reaction of oxygen, matches other electrochemical reactions, and constructs the overprotection mechanism of the aqueous zinc-manganese battery.

[0043] On the other hand, this application embodiment also provides an aqueous zinc-manganese battery, which includes the above-mentioned amphiphilic hydrogel electrolyte or the amphiphilic hydrogel electrolyte prepared by the above-mentioned method for preparing amphiphilic hydrogel electrolyte, and also includes a positive electrode and a negative electrode. The positive electrode is made of zinc foil. The negative electrode is made of manganese oxide, which includes at least one of manganese dioxide, lithium manganate, manganese oxide, manganese trioxide, manganese heptaoxide, and potassium manganate.

[0044] The following specific embodiments illustrate an amphiphilic hydrogel electrolyte and its preparation method provided in this application.

[0045] Example 1: This embodiment provides an amphiphilic hydrogel electrolyte and its preparation method, specifically including the following steps: 1. Prepare a solution with water as the solvent and zinc sulfate and manganese sulfate as the solutes, at a concentration of 1.2 mol / kg. 水 The initial electrolyte salt solution.

[0046] 2. The surfactant is added to the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant. Here, the surfactant is sodium dodecylbenzenesulfonate.

[0047] 3. The hydrophobic polymer chain monomer, hydrophilic polymer chain monomer, surfactant, and initiator are sequentially added to an electrolyte salt solution containing the surfactant, and then the mixture is heated in a sealed container at 70°C for 1 hour to obtain an amphiphilic hydrogel electrolyte. The molar ratio of the hydrophobic polymer chain monomer, hydrophilic polymer chain monomer, surfactant, and initiator is 0.05:4.0:0.01:0.06. In this embodiment, the hydrophobic polymer chain monomer is trifluoroethyl methacrylate, the hydrophilic polymer chain monomer is polyacrylamide, and the initiator is ammonium persulfate.

[0048] Comparative Example 1: This comparative example provides a common polyacrylamide hydrogel electrolyte and its preparation method. The only difference between Comparative Example 1 and Example 1 is that the polymer chain monomer in Comparative Example 1 only includes polyacrylamide, while the rest is the same as in Example 1, thus obtaining a common polyacrylamide hydrogel electrolyte.

[0049] Example 2: This embodiment 2 provides an amphiphilic hydrogel electrolyte and its preparation method, specifically including the following steps: 1. Prepare a solution with water as the solvent and zinc acetate and manganese acetate as the solutes, in a concentration of 1.5 mol / kg. 水 The initial electrolyte salt solution.

[0050] 2. The surfactant is added to the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant. Here, the surfactant is hexadecyltrimethylammonium bromide.

[0051] 3. Hydrophobic polymer chain monomers, hydrophilic polymer chain monomers, surfactants, and initiators are sequentially added to an electrolyte salt solution containing the surfactant. The mixture is then heated in a sealed container at 70°C for 1 hour to obtain an amphiphilic hydrogel electrolyte. The molar ratio of the hydrophobic polymer chain monomers, hydrophilic polymer chain monomers, surfactants, and initiators is 0.15:2.0:0.06:0.01. In this embodiment, the hydrophobic polymer chain monomer is dodecyl fluoroheptyl methacrylate, the hydrophilic polymer chain monomer is polyvinylpyrrolidone, and the initiator is ammonium persulfate.

[0052] Comparative Example 2: This comparative example provides a common polyvinylpyrrolidone hydrogel electrolyte and its preparation method. The only difference between Comparative Example 2 and Example 2 is that the polymer chain monomer in Comparative Example 2 only includes polyvinylpyrrolidone and does not contain hydrophobic polymer chain monomers. The rest is the same as in Example 2, and a common polyvinylpyrrolidone hydrogel electrolyte is obtained.

[0053] Example 3: This embodiment 3 provides an amphiphilic hydrogel electrolyte and its preparation method, specifically including the following steps: 1. Prepare a solution with water as the solvent and zinc trifluoromethanesulfonate and manganese trifluoromethanesulfonate as the solutes, at a concentration of 1.7 mol / kg. 水 The initial electrolyte salt solution.

[0054] 2. The surfactant is added to the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant. Here, the surfactant is sodium α-alkenylsulfonate.

[0055] 3. Hydrophobic polymer chain monomers, hydrophilic polymer chain monomers, surfactants, and initiators are sequentially added to an electrolyte salt solution containing the surfactant. The mixture is then heated in a sealed container at 70°C for 1 hour to obtain an amphiphilic hydrogel electrolyte. The molar ratio of the hydrophobic polymer chain monomers, hydrophilic polymer chain monomers, surfactants, and initiators is 0.10:2.5:0.05:0.03. In this embodiment, the hydrophobic polymer chain monomer is octadecyl methacrylate, the hydrophilic polymer chain monomer is poly(N-isopropylacrylamide), and the initiator is ammonium persulfate.

[0056] Comparative Example 3: This comparative example provides a common polyacrylamide hydrogel electrolyte and its preparation method. The only difference between Comparative Example 3 and Example 3 is that the polymer chain monomer in Comparative Example 3 only includes N-isopropylacrylamide and does not contain hydrophobic polymer chain monomers. The rest is the same as in Example 3, and a common polyacrylamide hydrogel electrolyte is obtained.

[0057] Electrochemical performance tests were conducted on the electrolytes obtained in Examples 1-3 and Comparative Examples 1-3, respectively. The test items included electrochemical stability window, cycle stability, average discharge plateau, capacity retention, etc.

[0058] Specifically, the electrochemical stability window was tested as follows: the electrolytes obtained in Examples 1-3 and Comparative Examples 1-3 were assembled with titanium sheets and silver / silver chloride electrodes into a three-electrode half-cell configuration. Linear sweep voltammetry or cyclic voltammetry was used to test each three-electrode half-cell, and the test results are shown in Table 1.

[0059] Cycle life, average discharge plateau, and capacity retention were tested by assembling zinc-manganese batteries. Specifically, the electrolytes obtained in Examples 1-3 and Comparative Examples 1-3 were used to assemble batteries with zinc foil and manganese trioxide as electrodes. The electrochemical performance of each battery was then tested using existing methods, such as constant current charge-discharge testing, to obtain the average discharge plateau and capacity retention. Based on the capacity retention, the actual discharge capacity during the charge-discharge cycle could be determined. Comparing the actual discharge capacity with the theoretical value revealed whether additional energy contribution was generated. Specific testing methods are not detailed here. The test results are shown in Table 1.

[0060] Table 1

[0061] A comparison of the test results of Example 1 and Comparative Example 1 shows that the electrochemical stability window of the amphiphilic hydrogel electrolyte prepared in Example 1 is 3.2V, which is much higher than the electrochemical stability window (1.9V) of the polyacrylamide hydrogel electrolyte in Comparative Example 1. The battery corresponding to the amphiphilic hydrogel electrolyte of Example 1 has a high average discharge plateau of 1.91V and excellent performance with stable cycling for 1000 cycles. However, the battery corresponding to the ordinary polyacrylamide hydrogel electrolyte in Comparative Example 1 only has an average discharge plateau of 1.2V and can only be stably cycled for 500 cycles. It can be seen that the amphiphilic hydrogel electrolyte has significant improvements in average discharge plateau and cycle stability compared to the ordinary polyacrylamide hydrogel electrolyte. In addition, when the amphiphilic hydrogel electrolyte in Example 1 is used in an aqueous zinc-manganese battery, it can achieve an additional 200% capacity contribution based on the redox reaction of oxygen, thereby realizing the overprotection mechanism of the aqueous zinc-manganese battery. However, the battery assembled with the polyacrylamide hydrogel electrolyte in Comparative Example 1 cannot achieve additional capacity and does not have an overprotection mechanism.

[0062] A comparison of the test results of Example 2 and Comparative Example 2 shows that the amphiphilic hydrogel electrolyte prepared in Example 2 has an electrochemical stability window of 3.0V, which is significantly higher than the electrochemical stability window (1.6V) of the ordinary polyvinylpyrrolidone hydrogel electrolyte in Comparative Example 2. The battery corresponding to the amphiphilic hydrogel electrolyte of Example 2 exhibits a high average discharge plateau of 1.98V and excellent performance with stable cycling exceeding 1500 cycles. However, the battery corresponding to the ordinary polyacrylamide hydrogel electrolyte of Comparative Example 2 only has an average discharge plateau of 1.2V and can only achieve stable cycling for 500 cycles. Therefore, the amphiphilic hydrogel electrolyte shows significant improvements in average discharge plateau and cycle stability compared to the ordinary polyvinylpyrrolidone hydrogel electrolyte. Furthermore, when the amphiphilic hydrogel electrolyte in Example 2 is used in an aqueous zinc-manganese battery, it can achieve an additional 150% capacity contribution based on the redox reaction of oxygen, thereby realizing the overprotection mechanism of the aqueous zinc-manganese battery. In contrast, the battery assembled with the ordinary polyvinylpyrrolidone hydrogel electrolyte in Comparative Example 2 cannot achieve additional capacity and does not have an overprotection mechanism.

[0063] A comparison of the test results of Example 3 and Comparative Example 3 shows that the amphiphilic hydrogel electrolyte prepared in Example 3 has an electrochemical stability window of 3.1V, which is significantly higher than the electrochemical stability window (1.8V) of the ordinary poly(N-isopropylacrylamide) hydrogel electrolyte in Comparative Example 3. The battery corresponding to the amphiphilic hydrogel electrolyte in Example 3 exhibits a high average discharge plateau of 1.93V and excellent performance with stable cycling exceeding 2000 cycles. However, the battery corresponding to the ordinary polyacrylamide hydrogel electrolyte in Comparative Example 3 only has an average discharge plateau of 1.2V and can only achieve stable cycling for 500 cycles. Therefore, the amphiphilic hydrogel electrolyte shows significant improvements in average discharge plateau and cycle stability compared to the ordinary poly(N-isopropylacrylamide) hydrogel electrolyte. Furthermore, when the amphiphilic hydrogel electrolyte in Example 3 is used in an aqueous zinc-manganese battery, it can achieve an additional 250% capacity contribution based on the redox reaction of oxygen, thereby realizing the overprotection mechanism of the aqueous zinc-manganese battery. In contrast, the battery assembled with the ordinary poly(N-isopropylacrylamide) hydrogel electrolyte in Comparative Example 2 cannot achieve additional capacity and does not have an overprotection mechanism.

[0064] In summary, when hydrogel electrolytes do not contain hydrophobic polymer chain monomers, they cannot contribute additional capacity and therefore do not undergo additional redox reactions, thus lacking an over-protection mechanism. However, the amphiphilic hydrogel electrolyte provided in this application, due to its unique gel polymer chain structure, can promote the oxygen reduction reaction involving 2 electron transfer on the zinc anode surface of the aqueous zinc-manganese battery, and achieve the self-oxidation reaction of manganese dioxide on the positive electrode side of the aqueous zinc-manganese battery, thereby providing additional discharge capacity and realizing an over-discharge protection mechanism for the aqueous zinc-manganese battery.

[0065] In summary, the amphiphilic hydrogel electrolyte prepared in the embodiments of this application has the following advantages: 1. By regulating the hydrophobic units of amphiphilic hydrogel electrolytes, the interaction between hydrophilic functional groups and water molecules in the amphiphilic hydrogel electrolyte can be enhanced under neutral conditions, thereby broadening the electrochemical stability window of aqueous zinc-manganese batteries for the application of neutral hydrogel electrolytes, so as to activate and stabilize the average high discharge platform of aqueous zinc-manganese batteries using high-voltage scanning technology.

[0066] 2. In amphiphilic hydrogel electrolytes, the hydrophobic segments of the hydrophobic polymer chains can undergo hydrophobic association interactions with the hydrophobic regions of the contacting objects, thereby complexing with them and forming a special environment at the interface. Under the influence of an electric field, this promotes the redox reaction of oxygen, matches other electrochemical reactions, and achieves additional capacity contribution, thus constructing the overprotection mechanism of aqueous zinc-manganese batteries.

[0067] On the other hand, this application also provides an aqueous zinc-manganese battery, including the above-mentioned amphiphilic hydrogel electrolyte or the amphiphilic hydrogel electrolyte prepared by the above-mentioned preparation method, a positive electrode, and a negative electrode. The positive electrode is made of zinc foil. The negative electrode is made of manganese oxide, which includes at least one of manganese dioxide, lithium manganate, manganese oxide, manganese trioxide, manganese heptaoxide, and potassium manganate.

[0068] The aqueous zinc-manganese battery provided in this application uses the amphiphilic hydrogel electrolyte prepared in the above embodiments, which can broaden the electrochemical stability window of the hydrogel electrolyte in a neutral environment. The high-voltage scanning technology path is used to activate and stabilize the electrochemical reaction of manganese dioxide deposition and dissolution, thereby achieving an average discharge voltage of 1.98V in the aqueous zinc-manganese battery. At the same time, based on the special polymer chain structure, it can achieve additional capacity contribution based on the redox reaction of oxygen, thereby realizing the over-discharge protection mechanism of the aqueous zinc-manganese battery.

[0069] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0070] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing an amphiphilic hydrogel electrolyte, characterized in that, The preparation method includes: The solution provides a surfactant, an initial electrolyte solution, a hydrophobic polymer chain monomer, a hydrophilic polymer chain monomer, and an initiator; the electrolyte salt solution is a mixed solution of an electrolyte zinc salt and an electrolyte manganese salt. The surfactant is dissolved in the initial electrolyte salt solution to obtain an electrolyte salt solution containing the surfactant; The hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, and the initiator are dissolved sequentially in the electrolyte salt solution containing the surfactant, and then heated to obtain an amphiphilic hydrogel electrolyte.

2. The preparation method according to claim 1, characterized in that, The method further includes: The initial electrolyte salt solution is prepared by dissolving the zinc electrolyte salt and the manganese electrolyte salt in water; The initial electrolyte salt solution satisfies at least one of the following characteristics: The volume concentration of the electrolyte salt solution is 1 mol / kg. 水 -2mol / kg 水 ; In the initial electrolyte salt solution, the molar ratio of the zinc electrolyte salt to the manganese electrolyte salt is 1:(0.1-0.6).

3. The preparation method according to claim 1, characterized in that, The molar ratio of the hydrophobic polymer chain monomer, the hydrophilic polymer chain monomer, the surfactant, and the initiator is (0.05-0.15):(2.0-4.0):(0.01-0.06):(0.01-0.06).

4. The preparation method according to claim 1, characterized in that, The electrolyte zinc salt includes any one or more of zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)imine zinc, and bis(pentafluoroethylsulfonyl)imine zinc; The electrolyte manganese salt includes any one or more of manganese sulfate, manganese chloride, manganese acetate, manganese trifluoromethanesulfonate, bis(trifluoromethanesulfonic acid)iminomanganese, and bis(pentafluoroethylsulfonyl)iminomanganese.

5. The preparation method according to claim 1, characterized in that, The hydrophilic polymer chain monomer includes any one of polyacrylamide, waterborne polyurethane, polymethyl methacrylate sulfonate betaine, polyvinylpyrrolidone, and polyN-isopropylacrylamide.

6. The preparation method according to claim 1, characterized in that, The hydrophobic polymer chain monomer includes any one of butyl methacrylate, lauryl methacrylate, octadecyl methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoroisopropyl acrylate, and dodecafluoroheptyl methacrylate.

7. The preparation method according to claim 1, characterized in that, The surfactant includes any one of bis(octadecyldimethylammonium chloride), hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium α-olefin sulfonate.

8. The preparation method according to claim 1, characterized in that, The initiator is ammonium persulfate.

9. An amphiphilic hydrogel electrolyte, characterized in that, It is prepared by the method for preparing amphiphilic hydrogel electrolyte as described in any one of claims 1-8; the amphiphilic hydrogel electrolyte includes electrolyte zinc salt, electrolyte manganese salt, hydrophobic polymer chain monomer, hydrophilic polymer chain monomer and water.

10. An aqueous zinc-manganese battery, characterized in that, Includes the amphiphilic hydrogel electrolyte, positive electrode, and negative electrode as described in claim 9; The positive electrode is made of zinc foil. The negative electrode is made of manganese oxide, which includes at least one of manganese dioxide, lithium manganate, manganese oxide, manganese trioxide, manganese heptaoxide, and potassium manganate.

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