Preparation method of modified zinc negative electrode, modified zinc negative electrode and aqueous zinc ion battery

Abstract

The application discloses a modified zinc negative electrode preparation method, a modified zinc negative electrode and an aqueous zinc ion battery, and belongs to the technical field of zinc ion batteries. The modified zinc negative electrode preparation method comprises the following steps: diluting a tetrahydroxymethyl phosphonium chloride (THPC) solution with a mass ratio of 80% to a certain concentration, uniformly stirring, and forming a treatment solution; cutting a zinc negative electrode, and performing surface oil stain treatment on the zinc negative electrode; immersing the treated zinc negative electrode in the THPC treatment solution at room temperature, and allowing the zinc negative electrode to react; after the reaction is completed, washing the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, and drying the zinc negative electrode in a vacuum drying box to obtain a modified zinc negative electrode. The modified zinc negative electrode preparation method, the modified zinc negative electrode and the aqueous zinc ion battery can solve the problem of poor cycle stability of the modified zinc negative electrode in an aqueous electrolyte.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of zinc ion batteries, in particular to a modified zinc negative electrode preparation method, a modified zinc negative electrode and an aqueous zinc ion battery. BACKGROUND

[0002] Metallic zinc as a negative electrode material has the advantages of high theoretical capacity, low redox potential, abundant reserves, and high chemical stability in aqueous solution. Therefore, aqueous zinc ion batteries based on zinc negative electrodes have broad prospects in the field of grid-scale energy storage. However, zinc negative electrodes still face many challenges in use, including zinc dendrites formed by uneven deposition, and side reactions such as corrosion, passivation and hydrogen evolution caused by water in the electrolyte.

[0003] Currently, the modification strategies for the above problems mainly include electrolyte optimization, separator optimization, negative electrode protection / structure design, etc. The methods of negative electrode protection / structure design include: ① negative electrode protection layer construction. A protective layer is introduced on the zinc negative electrode by physical or chemical methods, or a solid-state electrolyte interface is generated in situ. ② Negative electrode structure design. Design a 3D porous current collector, or use a porous material as a zinc carrier.

[0004] However, these methods still have some shortcomings. For example, the preparation of the interface protection layer requires complex vacuum deposition, atomic layer deposition and other technologies, which are costly and difficult to mass-produce. The interface bonding force between the artificial protection layer and the zinc negative electrode is weak, and it is easy to fall off and fail during long cycle process. The too dense protection layer will seriously hinder the transmission of Zn 2+ , increase the polarization, and reduce the rate performance of the battery. The development and design of 3D current collectors are complex and difficult to produce industrially.

[0005] Therefore, it is essential to develop a zinc negative electrode modification technology that is simple in process, low in cost, can effectively suppress dendrites and side reactions, and does not harm the dynamic performance of the battery, which is crucial for promoting the commercial application of aqueous zinc ion batteries. SUMMARY

[0006] The purpose of the present application is to provide a modified zinc negative electrode preparation method, a modified zinc negative electrode and an aqueous zinc ion battery, which solves the problems of difficult preparation and high cost of the modified zinc negative electrode.

[0007] To achieve the above purpose, the present application provides a modified zinc negative electrode preparation method, which comprises the following steps:

[0008] S1, dilute a tetrahydroxymethyl phosphonium chloride solution with a mass ratio of 80% to a certain concentration, stir uniformly, and form a treatment solution;

[0009] S2, cutting the zinc negative electrode and performing surface treatment on the zinc negative electrode;

[0010] S3, immerging the treated zinc negative electrode in a tetramethylphosphonium chloride treatment solution at room temperature to react;

[0011] S4, after the reaction, rinsing the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, drying in a vacuum drying oven to obtain a modified zinc negative electrode.

[0012] Preferably, in S1, the volume concentration of tetramethylphosphonium chloride in the prepared treatment solution is 1%-7%.

[0013] Preferably, in S2, the thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is a pure zinc foil or a pure zinc plate.

[0014] Preferably, in S2, the surface treatment of the zinc negative electrode specifically comprises: sequentially ultrasonic cleaning the zinc negative electrode with deionized water and ethanol, the ultrasonic time being 30 minutes and the ultrasonic power being 25 W.

[0015] Preferably, in S3, the reaction time is 0.5h-10h.

[0016] Preferably, in S4, the drying temperature of the vacuum drying oven is 60℃, and the drying time is 4h.

[0017] A modified zinc negative electrode comprises:

[0018] a zinc negative electrode body,

[0019] a passivation-activation structure formed in situ on the surface of the zinc negative electrode body, the passivation-activation structure being formed by the above preparation method.

[0020] Preferably, the thickness of the zinc negative electrode body is 100 μm, and the zinc negative electrode body is a pure zinc foil or a pure zinc plate.

[0021] A water-based zinc ion symmetrical battery comprises a zinc electrode, a separator, an electrolyte and a zinc electrode, and the zinc electrode is the above modified zinc negative electrode.

[0022] A water-based zinc ion battery full cell comprises a zinc negative electrode, a separator, an electrolyte and a positive electrode, and the positive electrode is an ammonium vanadate positive electrode.

[0023] Preferably, the electrolyte of the symmetrical battery and the full cell is a 2 mol / L ZnSO4 solution, and the separator is a glass fiber separator or a commercial filter paper.

[0024] The modified zinc negative electrode preparation method, the modified zinc negative electrode and the water-based zinc ion battery have the following advantages and positive effects:

[0025] 1. The application forms a thin protective layer on the surface of the zinc negative electrode and activates the crystal face to obtain a passivation-activation structure by immersing the zinc negative electrode in a tetramethylphosphonium chloride treatment solution, effectively inhibits the formation of zinc dendrites, reduces the side reaction of the zinc negative electrode and the electrolyte, and effectively improves the cycle life of the water-based zinc ion battery.

[0026] 2. The method completes the reaction of the zinc negative electrode and the tetramethylphosphonium chloride treatment solution at room temperature, has low requirements on equipment, is simple to operate, effectively reduces the cost, and reduces the preparation difficulty of the modified zinc negative electrode.

[0027] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The surface scanning electron microscope photos of the zinc negative electrode without treatment in the comparative example 2 of the application, and the modified zinc negative electrodes prepared in the example 1, the example 2, and the example 3 are shown; (a), (b), and (c) are the scanning electron microscope photos of the comparative example 2, (d), (e), and (f) are the scanning electron microscope photos of the example 1, (g), (h), and (i) are the scanning electron microscope photos of the example 2, and (j), (k), and (l) are the scanning electron microscope photos of the example 3.

[0029] Figure 2 The surface scanning electron microscope photos of the zinc electrode treated by the tetramethylphosphonium chloride treatment solution in the example 4 are shown; (a) is the electron microscope photo under 200 μm, (b) is the electron microscope photo under 20 μm, (c) is the electron microscope photo under 5 μm, and (d) is the electron microscope photo under 2 μm.

[0030] Figure 3 The cycle performance of the symmetrical battery assembled by the example 1, the example 2, the comparative example 1, and the comparative example 2 of the application is shown; (a) is the cycle performance of the example 1, (b) is the cycle performance of the example 2, (c) is the cycle performance of the comparative example 1, and (d) is the cycle performance of the comparative example 2.

[0031] Figure 4 The cycle performance of the full battery assembled by the zinc negative electrode and the ammonium vanadate positive electrode described in the example 1 of the application under the current density of 1 A g -1 DETAILED DESCRIPTION

[0032] In the present application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. If there is any inconsistency, the meaning described in the present specification or the meaning derived from the content described in the present specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

[0033] ​Embodiments of the application will be described in detail below with reference to the drawings.

[0034] A method for preparing a modified zinc negative electrode, comprising the following steps:

[0035] S1, dilute a tetrahydroxymethyl phosphonium chloride solution with a mass ratio of 80% to a certain concentration, and stir uniformly to form a treatment solution. The volume concentration of tetrahydroxymethyl phosphonium chloride in the prepared treatment solution is 1%-7%. If the concentration of THPC is too low, the zinc electrode cannot be effectively etched, and if the concentration is too high, the active crystal surface will be excessively exposed, thereby aggravating the side reaction.

[0036] S2, cut the zinc negative electrode to the required size, and perform surface treatment on the zinc negative electrode.

[0037] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is a pure zinc foil or a pure zinc plate.

[0038] The surface treatment of the zinc negative electrode specifically comprises: sequentially performing ultrasonic cleaning on the zinc negative electrode with deionized water and ethanol, the ultrasonic time being 30 minutes and the ultrasonic power being 25 W, so as to remove the oil stains on the surface of the zinc negative electrode, and then drying after cleaning.

[0039] S3, immerse the treated zinc negative electrode in the tetrahydroxymethyl phosphonium chloride treatment solution at room temperature to react. The reaction time is 0.5h-10h.

[0040] S4, after the reaction is completed, rinse the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, and dry in a vacuum drying oven to obtain a modified zinc negative electrode.

[0041] The drying temperature of the vacuum drying oven is 60℃, and the drying time is 4h.

[0042] A modified zinc negative electrode, comprising:

[0043] a zinc negative electrode body,

[0044] An active zinc electrode structure is formed by etching the zinc substrate on the surface of the zinc negative electrode body through THPC and forming a passivation layer by covering the product. The passivation-activation structure is formed by the above preparation method.

[0045] The zinc negative electrode body is a pure zinc foil or a pure zinc plate.

[0046] The tetrahydroxymethyl phosphonium chloride is preferentially adsorbed on the surface of the zinc electrode, first reacts with the surface passivation layer, and removes the surface oxide film. Subsequently, the zinc 2+ The coordination occurs, the zinc substrate is etched, the active crystal surface is exposed, and the phosphorus-containing compound produced by the reaction covers the zinc substrate to form a uniform protective layer, and finally the zinc electrode structure with a passivation-activation structure is obtained.

[0047] The concentration of THPC is too low to provide sufficient THPC molecules to react with the zinc surface, resulting in the inability to remove the oxide layer on the surface of the zinc anode. The concentration of THPC is too high, and the excess THPC molecules will promote the corrosion reaction, and the exposure of a large number of active crystal surfaces will exacerbate the hydrogen evolution, passivation and other side reactions. Therefore, the volume concentration of THPC in the treatment solution is 1%-7%.

[0048] The immersion time of the zinc anode is too short, and the reaction of tetrahydroxymethyl phosphonium chloride (THPC) with the zinc anode is insufficient, making it difficult to form a stable passivation-activation structure and unable to play a modification role. When the reaction time is too long, the continuous reaction will cause the passivation layer to be damaged, and the active crystal surface is excessively exposed. Therefore, the immersion time of the zinc anode in the treatment solution is 0.5h-10h.

[0049] The passivation-activation structure formed on the surface of the zinc anode can inhibit the uneven deposition of zinc dendrites. Zinc dendrites are the key problem that leads to the cycle failure of aqueous zinc ion batteries (will pierce the separator and cause short circuit). The active zinc substrate significantly increases the specific surface area of the electrode, effectively reduces the local current density, and guides Zn 2+ to deposit uniformly, avoiding the formation of dendrites on the surface of the negative electrode; at the same time, the anisotropic crystal surface produced by etching can buffer the stress during the deposition / dissolution process, maintain the long-term integrity of the electrode structure, and effectively improve the cycle life of the battery. 2+ The passivation-activation structure formed on the surface of the zinc anode can inhibit the uneven deposition of zinc dendrites. Zinc dendrites are the key problem that leads to the cycle failure of aqueous zinc ion batteries (will pierce the separator and cause short circuit). The active zinc substrate significantly increases the specific surface area of the electrode, effectively reduces the local current density, and guides Zn 2+ to deposit uniformly, avoiding the formation of dendrites on the surface of the negative electrode; at the same time, the anisotropic crystal surface produced by etching can buffer the stress during the deposition / dissolution process, maintain the long-term integrity of the electrode structure, and effectively improve the cycle life of the battery.

[0050] The inert protective layer on the surface of the zinc anode can reduce the side reactions between the zinc anode and the electrolyte. Water in the aqueous electrolyte will have side reactions such as corrosion and hydrogen evolution with the zinc anode (generate corrosive byproducts, consume zinc active material), resulting in a decrease in coulombic efficiency and a decrease in cycle life. The negative electrode protection layer can effectively isolate the direct contact between the zinc anode surface and the electrolyte, greatly reduce the hydrogen evolution reaction and the generation of corrosive byproducts; at the same time, the protective layer will not hinder the normal transmission of Zn 2+ (avoiding increased polarization), while inhibiting side reactions (reducing hydrogen evolution and reducing the amount of corrosive byproduct generation), ensuring the efficient migration of Zn 2+ , improving the cycle stability and coulombic efficiency of the battery.

[0051] An aqueous zinc ion symmetrical battery includes a zinc electrode, a separator, an electrolyte and a zinc electrode, the zinc electrode is the modified zinc anode described above.

[0052] The electrolyte of the symmetrical battery is a 2 mol / L ZnSO4 solution, and the separator is a glass fiber separator or a commercial filter paper.

[0053] A water-based zinc ion all-battery includes a positive electrode, a separator, an electrolyte, and a zinc negative electrode, the zinc negative electrode is the modified zinc negative electrode, the positive electrode is an ammonium vanadate positive electrode, the electrolyte is a 2 mol / L ZnSO4 solution, and the separator is a glass fiber separator or a commercial filter paper.

[0054] Embodiment 1

[0055] A modified zinc negative electrode preparation method includes the following steps:

[0056] S1, dilute the tetramethylammonium chloride solution with a mass ratio of 80% to a certain concentration, stir uniformly, and form a treatment solution. The volume concentration of tetramethylammonium chloride in the prepared treatment solution is 1.25%.

[0057] S2, cut the zinc negative electrode to the required size, and perform surface treatment on the zinc negative electrode.

[0058] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is a pure zinc foil or a pure zinc plate.

[0059] The surface treatment of the zinc negative electrode is specifically: ultrasonic cleaning of the zinc negative electrode with deionized water and ethanol, ultrasonic time is 30 minutes, ultrasonic power is 25W, to remove the oil stains on the surface of the zinc negative electrode, and dry after cleaning.

[0060] S3, immerse the treated zinc negative electrode in the tetramethylammonium chloride treatment solution at room temperature, and react. The reaction time is 3h.

[0061] S4, after the reaction is completed, wash the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, dry in a vacuum drying oven, and obtain a modified zinc negative electrode.

[0062] The drying temperature of the vacuum drying oven is 60℃, and the drying time is 4h.

[0063] Embodiment 2

[0064] A modified zinc negative electrode preparation method includes the following steps:

[0065] S1, dilute the tetramethylammonium chloride solution with a mass ratio of 80% to a certain concentration, stir uniformly, and form a treatment solution. The volume concentration of tetramethylammonium chloride in the prepared treatment solution is 1.25%.

[0066] S2, cut the zinc negative electrode to the required size, and perform surface treatment on the zinc negative electrode.

[0067] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is a pure zinc foil or a pure zinc plate.

[0068] The surface treatment of the zinc negative electrode specifically comprises: sequentially performing ultrasonic cleaning on the zinc negative electrode with deionized water and ethanol, the ultrasonic time being 30 minutes and the ultrasonic power being 25 W, so as to remove oil stains on the surface of the zinc negative electrode, and drying after cleaning.

[0069] S3, immerse the treated zinc negative electrode in a tetramethylphosphonium chloride treatment solution at room temperature to react.

[0070] S4, after the reaction is completed, flush the residual solution on the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, and dry in a vacuum drying box to obtain a modified zinc negative electrode.

[0071] The drying temperature of the vacuum drying box is 60 DEG C, and the drying time is 4 h.

[0072] Example 3

[0073] A modified zinc negative electrode preparation method comprises the following steps:

[0074] S1, dilute a tetramethylphosphonium chloride solution with a mass ratio of 80% to a certain concentration, and stir uniformly to form a treatment solution. The volume concentration of tetramethylphosphonium chloride in the prepared treatment solution is 1.25%.

[0075] S2, cut the zinc negative electrode into a required size, and perform surface treatment on the zinc negative electrode.

[0076] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is a pure zinc foil or a pure zinc plate.

[0077] The surface treatment of the zinc negative electrode specifically comprises: sequentially performing ultrasonic cleaning on the zinc negative electrode with deionized water and ethanol, the ultrasonic time being 30 minutes and the ultrasonic power being 25 W, so as to remove oil stains on the surface of the zinc negative electrode, and drying after cleaning.

[0078] S3, immerse the treated zinc negative electrode in a tetramethylphosphonium chloride treatment solution at room temperature to react.

[0079] S4, after the reaction is completed, flush the residual solution on the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, and dry in a vacuum drying box to obtain a modified zinc negative electrode.

[0080] The drying temperature of the vacuum drying box is 60 DEG C, and the drying time is 4 h.

[0081] Example 4

[0082] A modified zinc negative electrode preparation method comprises the following steps:

[0083] S1, dilute the tetramethylammonium chloride solution with a mass ratio of 80% to a certain concentration, stir uniformly to form a treatment solution. The volume concentration of tetramethylammonium chloride in the prepared treatment solution is 6.25%.

[0084] S2, cut the zinc negative electrode to the required size, and perform surface treatment on the zinc negative electrode.

[0085] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is pure zinc foil or pure zinc plate.

[0086] The surface treatment of the zinc negative electrode is specifically: sequentially performing ultrasonic cleaning on the zinc negative electrode with deionized water and ethanol, the ultrasonic time is 30 minutes, and the ultrasonic power is 25 W, so as to remove the oil stains on the surface of the zinc negative electrode, and drying after cleaning.

[0087] S3, immerse the treated zinc negative electrode in the tetramethylammonium chloride treatment solution at room temperature to react. The reaction time is 9h.

[0088] S4, after the reaction is completed, rinse the surface of the reacted zinc negative electrode with deionized water and anhydrous ethanol, and dry in a vacuum drying box to obtain a modified zinc negative electrode.

[0089] The drying temperature of the vacuum drying box is 60℃, and the drying time is 4h.

[0090] Figure 2 The microstructure of the zinc foil etched by the 6.25% THPC treatment solution for 9h can be seen from Figure 2 It can be seen that after being treated by the 6.25% THPC solution for 9h, obvious crystal faces and grain boundaries can be observed on the surface of the zinc foil, but no obvious passivation layer can be observed.

[0091] Comparative Example 1

[0092] A modified zinc negative electrode preparation method comprises the following steps:

[0093] S1, dilute the tetramethylammonium chloride solution with a mass ratio of 80% to a certain concentration, stir uniformly to form a treatment solution. The volume concentration of tetramethylammonium chloride in the prepared treatment solution is 1.25%.

[0094] S2, cut the zinc negative electrode to the required size, and perform surface treatment on the zinc negative electrode.

[0095] The thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is pure zinc foil or pure zinc plate.

[0096] The surface treatment of the zinc negative electrode is specifically: sequentially performing ultrasonic cleaning on the zinc negative electrode with deionized water and ethanol, the ultrasonic time is 30 minutes, and the ultrasonic power is 25 W, so as to remove the oxide layer and oil stains on the surface of the zinc negative electrode, and drying after cleaning.

[0097] S3. The treated zinc anode is immersed in a tetrahydroxymethylphosphoric acid treatment solution at room temperature to allow the reaction to occur. The reaction time is 15 hours.

[0098] S4. After the reaction is complete, rinse the surface of the zinc anode with deionized water and anhydrous ethanol to remove the residual solution, and then dry it in a vacuum drying oven to obtain the modified zinc anode.

[0099] The drying temperature of the vacuum drying oven is 60℃, and the drying time is 4 hours.

[0100] Comparative Example 2

[0101] In this comparative example, the zinc anode was not subjected to immersion treatment with tetrahydroxymethylphosphoric acid. The zinc anode underwent the following treatment.

[0102] The zinc negative electrode is cut to the required size and then surface-treated.

[0103] The zinc anode is 100 μm thick and is made of pure zinc foil or pure zinc plate.

[0104] The surface treatment of the zinc anode involved sequentially ultrasonically cleaning it with deionized water and ethanol for 30 minutes at a power of 25W. After cleaning, the anode was placed in a vacuum drying oven at 60℃ for 4 hours.

[0105] The microstructure of the modified zinc anodes prepared in Examples 1, 2, and 1 was observed, and the scanning electron microscope images are shown below. Figure 1 As shown. From Figure 1 It can be seen that after treatment with the same concentration of THPC solution, the oxide layer on the surface of the zinc anode is gradually etched, and as the treatment time increases, the crystal planes and grain boundaries of metallic zinc are gradually exposed.

[0106] Comparative Example 2: Microstructure of the zinc anode surface without immersion treatment with tetramethylphosphoric acid (TMP) is as follows. Figure 1 As shown, from Figure 1 It can be seen that the zinc electrode surface has a texture produced by processing and manufacturing, and due to the presence of inert compounds (ZnO, Zn(OH)2, etc.), the grain boundaries and crystal planes of zinc cannot be observed on the bare zinc electrode surface.

[0107] The modified zinc anodes prepared in Examples 1-2 and Comparative Examples 1 and 2 were assembled into Zn|Zn symmetrical cells. The electrodes of the symmetrical cells were the modified zinc anodes described above, the electrolyte was a 2 mol / L ZnSO4 solution, and the separator was a glass fiber membrane or commercial filter paper. The assembled symmetrical cells were tested at 1 mA / cm². 2 Current density and 1mAh / cm 2The constant current charge-discharge test was carried out under the surface capacity of 1mAh / cm2.

[0108] The cycle performance of the symmetric battery assembled in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 is shown in Figure 3 Figure 3 It can be seen from the figure that, although the cycle stability of the zinc negative electrode in the symmetric battery first increases and then decreases with the extension of the treatment time, when the zinc negative electrode treated by THPC is used as the negative electrode, the cycle life is much higher than that of the untreated zinc electrode. Especially under the condition of a current density of 1mA / cm2and a surface capacity of 1mAh / cm2, the cycle life of the zinc negative electrode treated by 1.25% THPC treatment solution for 3h and 6h is 420h and 1100h respectively, which is much higher than that of the untreated zinc negative electrode (less than 100h). 2 2 It can be seen from the figure that, although the cycle stability of the zinc negative electrode in the symmetric battery first increases and then decreases with the extension of the treatment time, when the zinc negative electrode treated by THPC is used as the negative electrode, the cycle life is much higher than that of the untreated zinc electrode. Especially under the condition of a current density of 1mA / cm2and a surface capacity of 1mAh / cm2, the cycle life of the zinc negative electrode treated by 1.25% THPC treatment solution for 3h and 6h is 420h and 1100h respectively, which is much higher than that of the untreated zinc negative electrode (less than 100h).

[0109] The cycle performance of the full battery based on the zinc negative electrode prepared in Example 1 and the ammonium vanadate positive electrode after 1000 cycles at a current density of 1A / g is shown in Figure 4 It can be seen from the figure that, although the cycle stability of the zinc negative electrode in the symmetric battery first increases and then decreases with the extension of the treatment time, when the zinc negative electrode treated by THPC is used as the negative electrode, the cycle life is much higher than that of the untreated zinc electrode. Especially under the condition of a current density of 1mA / cm2and a surface capacity of 1mAh / cm2, the cycle life of the zinc negative electrode treated by 1.25% THPC treatment solution for 3h and 6h is 420h and 1100h respectively, which is much higher than that of the untreated zinc negative electrode (less than 100h).

[0110] Therefore, the modified zinc negative electrode prepared by the preparation method of the modified zinc negative electrode, the modified zinc negative electrode and the aqueous zinc ion battery can solve the problems of poor cycle stability, difficult preparation and high cost of the modified zinc negative electrode.

[0111] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.​​

Claims

1. A method for preparing a modified zinc anode, characterized in that, Includes the following steps: S1. Dilute the 80% tetrahydroxymethyl phosphorus chloride solution to a certain concentration, stir evenly, and form a treatment solution; S2. After cutting the zinc negative electrode, perform surface treatment on the zinc negative electrode; S3. The treated zinc anode is immersed in a tetrahydroxymethylphosphoric acid treatment solution at room temperature to allow the reaction to occur; S4. After the reaction is complete, rinse the surface of the zinc anode with deionized water and anhydrous ethanol to remove the residual solution, and then dry it in a vacuum drying oven to obtain the modified zinc anode. In step S1, the volume concentration of tetrahydroxymethylphosphoric acid in the prepared treatment solution is 1%-7%; In S3, the reaction time is 0.5h-10h.

2. The method for preparing a modified zinc anode according to claim 1, characterized in that: In S2, the thickness of the zinc negative electrode is 100 μm, and the zinc negative electrode is pure zinc foil or pure zinc plate.

3. The method for preparing a modified zinc anode according to claim 1, characterized in that: In step S2, the surface treatment of the zinc anode specifically involves ultrasonically cleaning the zinc anode with deionized water and ethanol in sequence for 30 minutes at a power of 25W.

4. The method for preparing a modified zinc anode according to claim 1, characterized in that: In step S4, the drying temperature of the vacuum drying oven is 60°C, and the drying time is 4 hours.

5. A modified zinc anode, characterized in that, include: Zinc anode body, A passivation-activation structure is formed in situ on the surface of the zinc anode body, and the passivation-activation structure is formed by the preparation method described in any one of claims 1-4.

6. A modified zinc anode according to claim 5, characterized in that: The thickness of the zinc anode body is 100μm, and the zinc anode body is pure zinc foil or pure zinc plate.

7. An aqueous zinc-ion battery, a complete battery, comprising a positive electrode, a separator, an electrolyte, and a zinc negative electrode, characterized in that: The zinc anode is the modified zinc anode as described in claim 6, the cathode is ammonium vanadate cathode, the electrolyte is a 2 mol / L ZnSO4 solution, and the diaphragm is a glass fiber diaphragm or commercial filter paper.

8. An aqueous zinc-ion battery, which is a symmetrical battery, characterized in that: It includes a zinc electrode, a diaphragm, an electrolyte, and a zinc electrode, wherein the zinc electrode is the modified zinc anode as described in claim 6, the electrolyte is a 2 mol / L ZnSO4 solution, and the diaphragm is a glass fiber diaphragm or commercial filter paper.

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