Preparation and application of aqueous zinc-ion battery and modified zinc anode thereof

Abstract

The application belongs to the field of aqueous zinc ion batteries, and particularly relates to preparation and application of an aqueous zinc ion battery and a modified zinc negative electrode thereof; the modified zinc negative electrode comprises a zinc substrate and a modified coating layer combined on the surface of the zinc substrate; the modified coating layer comprises a binder and a modifier of formula A. The application innovatively coats the zinc substrate with a functional coating layer of formula A structure, the functional coating layer has excellent stability and a fast zinc ion conduction rate, and can still exhibit excellent stability under high discharge depth and large current density.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of zinc ion batteries, and particularly relates to the field of zinc metal negative electrode materials. BACKGROUND

[0002] With the increasing environmental problems, the continuous depletion of fossil energy and the continuous decline of mineral resources grade, it is urgent to develop a new electrochemical energy storage system. Due to the unique advantages of zinc, such as 820 mAh·g -1 -0.76 V vs. standard hydrogen electrode (SHE), and non-toxic characteristics, aqueous zinc ion batteries (ZIBs) are becoming one of the most promising candidates. One of the primary problems limiting the commercial application of aqueous zinc ion batteries is the hydrogen evolution reaction (HER) of zinc metal electrode in aqueous electrolyte, which leads to the dissolution of zinc electrode. Secondly, the local pH increase caused by the hydrogen evolution reaction leads to the continuous proliferation of by-products, causing the loss of zinc electrode. In addition, the uneven surface of the zinc electrode leads to the growth of zinc dendrites, which eventually pierces the separator and causes short circuit of the battery, which limits its commercial application.

[0003] The current solution to zinc negative electrode side reaction and inhibition of zinc dendrite growth is to modify the electrolyte. The main method of electrolyte modification is to change the solvent of the electrolyte, the electrolyte salt or add additives. However, electrolyte modification greatly increases the ohmic resistance of the overall battery, resulting in a loss of battery energy density. Simple modification on the electrolyte side has limited effect on alleviating side reactions and zinc dendrites. Non-electrochemically active additives greatly reduce the conductivity of the zinc negative electrode, masking the advantages of the huge theoretical specific capacity of the zinc negative electrode. Therefore, the application of electrolyte modification on the zinc negative electrode is very limited.

[0004] In view of the problems faced by zinc negative electrode coating, the prior art also reports some improvement means. For example, the Chinese patent document with publication number CN119133356A discloses a zinc negative electrode coated with expanded graphite embedded titanium quantum dots protection. The Chinese patent document with publication number CN119208502A discloses a preparation method and application of a zinc negative electrode with a MCM-41 protective layer. The Chinese patent document with publication number CN119208501A discloses a zinc foil negative electrode modified by a eutectic gel coating. The Chinese patent document with publication number CN119108546A discloses a modified zinc electrode material, which adopts electrochemical polymerization to coat PEDOT coating on the zinc negative electrode material; the coating thickness is 30-65 μm. In addition, the Chinese patent document with publication number CN119009183A discloses an aqueous zinc ion battery coating, which includes a binder and a polyhedral cerium-iron Prussian blue (D-CeFe-PBA).

[0005] In summary, although the prior art discloses some improved coating schemes, the electrochemical stability of the obtained material at high discharge depth and large current density still needs to be improved. SUMMARY

[0006] In view of the problems of side reactions and zinc dendrite growth of the existing zinc negative electrode material, especially the unsatisfactory service life at high discharge depth, the first object of the present application is to provide a modified zinc negative electrode, which aims to provide a zinc negative electrode with excellent performance, especially excellent electrochemical stability at high discharge depth and large current density.

[0007] The second object of the present application is to provide a preparation method of the modified zinc negative electrode, which aims to construct the super-hydrophobic coating material based on a multi-step process.

[0008] The third object of the present application is to provide an application of the modified zinc negative electrode in a zinc ion battery negative electrode.

[0009] The fourth object of the present application is to provide an aqueous zinc ion battery comprising the modified zinc negative electrode.

[0010] A modified zinc negative electrode comprises a zinc substrate and a modified coating layer compounded on the surface of the zinc substrate; the modified coating layer comprises a binder and a modified agent of formula A.

[0011]

[0012] In the formula A, R1-R5 are independently H, alkyl, hydroxyl, alkoxy, carboxyl, nitro, trifluoromethyl or halogen, wherein R1-R5 are not H at the same time; R6 is H, Na, K or NH4.

[0013] The present application innovatively coats a functional coating layer with the structure of formula A on the surface of the zinc substrate, which has excellent stability and fast zinc ion conduction rate, and can also exhibit excellent stability at high discharge depth and large current density.

[0014] In the present application, the zinc substrate is a zinc foil, for example, the thickness thereof is 5-15 mu m, and further can be 8-12 mu m.

[0015] In the present application, the zinc substrate is a zinc substrate which is sequentially subjected to modification treatment by alkaline solution and acid solution.

[0016] In formula A of the present application, the configuration of the double bond is not particularly required, and considering the cost, it can be trans In addition, the alkyl group can be a linear or branched C1-C10 alkyl group. The alkoxy group can be a linear or branched C1-C10 alkoxy group.

[0017] The research of the application shows that further optimization and control of the structure of formula A of the modified coating can further improve the electrochemical performance of the modified zinc negative electrode at high discharge depth and large current.

[0018] In the formula A, R1, R4 and R5 are H, and R2 and R3 are independently hydroxyl, carboxyl or alkoxy.

[0019] Preferably, R3 is C1-C6 alkoxy, and R2 is hydroxyl. The research of the application shows that the preferred formula A can unexpectedly further adapt to the physicochemical characteristics of zinc ion batteries, and can further improve the electrochemical performance of the modified zinc negative electrode at high discharge depth and large current.

[0020] In the application, the binder includes at least one of PVDF, SBR and CMC; preferably, the weight ratio of PVDF and SBR is 1:0.5-2. The research of the application shows that the preferred binder can unexpectedly and further jointly cooperate with the formula A, and is helpful to further improve the electrochemical performance of the modified zinc negative electrode at high discharge depth and large current.

[0021] In the application, the content of the formula A in the modified coating is 70-85 wt.%; further, it can be 75-80 wt.%.

[0022] In the application, the modified coating further contains zinc metal embedded by electrochemical deposition. The research of the application shows that the innovative addition of the formula A, in combination with the electro-deposition process, is helpful to further improve the electrochemical performance of the modified zinc negative electrode at high discharge depth and large current.

[0023] Preferably, the embedded amount of zinc metal is 5-10 mg / cm 2 , further, it can be 6 mg / cm 2 -8 mg / cm 2 .

[0024] In the application, the thickness of the modified coating is not particularly required, for example, it can be 10-100 μm, further, it can be 30-60 μm.

[0025] The application further provides a preparation method of the modified zinc negative electrode. Formula A and a binder are slurried with a solvent to obtain a slurry, which is coated on the surface of a zinc substrate, dried, and a modified negative electrode with a modified coating compounded on the surface is prepared.

[0026] In the application, the zinc substrate is a zinc substrate sequentially modified by alkaline solution and acid solution.

[0027] Preferably, the alkaline solution is an aqueous solution dissolving one of sodium carbonate, sodium bicarbonate, sodium phosphate, disodium hydrogen phosphate as an alkaline solute; preferably, the concentration of the alkaline solute is 1-3 mol / l, preferably 1.5-2.4 mol / l; the time of the alkaline solution treatment is 10 min-2 h, preferably 0.5-1 h.

[0028] Preferably, the acid solution is an aqueous solution dissolving at least one of hydrochloric acid, sulfuric acid as an acid component.

[0029] Preferably, the concentration of the acid component is 0.1-0.5 mol / l, preferably 0.3-0.4 mol / l.

[0030] Preferably, the acid solution further comprises a corrosion inhibitor.

[0031] Preferably, the corrosion inhibitor comprises at least one of sodium methylbenzenesulfonate, sodium thiocyanate and aniline.

[0032] Preferably, the content of the corrosion inhibitor in the acid solution is 1 wt‰-10 wt‰, preferably 2.5 wt‰-5 wt‰.

[0033] Preferably, the time of the acid solution treatment is 0.5 h-3 h, preferably 1.25-2 h.

[0034] After the acid solution treatment, the zinc substrate is obtained by washing with water, organic solvent and drying.

[0035] In the present application, the solvent comprises at least one of NMP, DMF and the like.

[0036] In the present application, the component comprising formula A and the binder can be coated on the zinc substrate by conventional coating or printing and the like. The thickness of the coating can be adjusted as required, for example, it can be 10-100 μm, further it can be 30-60 μm. After coating, drying treatment can be performed by conventional means.

[0037] Preferably, the dried electrode sheet is subjected to rolling and / or heat treatment. The present application shows that further in combination with the rolling treatment, the effect of formula A can be further strengthened, which is helpful to further improve the high discharge depth and the electrochemical performance under large current of the obtained modified electrode.

[0038] In one preferred embodiment of the present application, the modified negative electrode with the modified coating on the surface is used as a negative electrode, graphite is used as an anode, and the modified zinc negative electrode with zinc embedded in the modified coating is prepared by electrodeposition in an electrolyte containing zinc ions and electrochemical deposition of zinc in the modified coating. The present application shows that in combination with the electrodeposition treatment, the high discharge depth and the electrochemical performance under large current of the modified zinc negative electrode can be further improved in combination with the innovative addition of formula A.

[0039] The electrolyte of the electrodeposition stage can be, for example, a zinc sulfate solution, the solute of which can have a concentration of 1 mol / l to 6 mol / l, preferably 2 mol / l to 4.5 mol / l. The current density of the electrodeposition stage is 1 mA / cm 2 ~ 5 mA / cm 2 , preferably 2 mA / cm 2 ~ 4.1 mA / cm 2 . The relative distance between the two electrodes is 3 cm to 10 cm, preferably 5 cm to 7.5 cm. The electrodeposition time is 0.5 h to 2 h, preferably 1 h to 1.25 h.

[0040] The application also provides the use of the modified zinc negative electrode as a negative electrode for preparing a water-based zinc ion battery.

[0041] In the application, the modified zinc negative electrode can be used as a negative electrode based on known principles and means to prepare a water-based zinc ion battery.

[0042] The application also provides a water-based zinc ion battery comprising the modified zinc negative electrode.

[0043] The water-based zinc ion battery described in the application can comprise the modified zinc negative electrode and other components and structural parts known in the art.

[0044] Advantages

[0045] 1. The application innovatively coats the zinc substrate with a functional coating layer of structure A, which has excellent water corrosion resistance and stable structure, and has a high zinc ion conduction rate, and can still exhibit excellent stability under high current density and large surface capacity.

[0046] 2. In the application, further optimization of the structure of formula A, and / or modification of the zinc substrate, and / or the adhesive component, and / or the electrodeposition zinc process, can further enhance the effect of formula A and further improve the stability of the zinc negative electrode under high current density and large surface capacity. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 SEM image of the zinc electrode finally prepared in Example 1; DETAILED DESCRIPTION

[0048] The application will be further described in detail below in conjunction with specific examples, but the application is not limited to the following examples.

[0049] The modified zinc negative electrode described in the application comprises a zinc substrate and a modified coating layer compounded on the surface thereof; the modified coating layer comprises an adhesive and a modified agent of formula A.

[0050] In the present application, the zinc metal substrate is an ultra-thin zinc foil with a thickness of 10±2 μm.

[0051] In the present application, the zinc substrate can be pretreated by alkaline treatment, acid treatment (acid etching), water washing, and organic solvent washing.

[0052] In the present application, the alkaline washing solution is composed of an inorganic base and ultrapure water. The inorganic base is one of sodium carbonate, sodium bicarbonate, sodium phosphate, and disodium hydrogen phosphate. The ultrapure water has a resistivity of >18 MΩ / cm.

[0053] In the present application, the concentration of the inorganic base in the alkaline washing solution is 1-3 mol / l, preferably 1.5-2.4 mol / l.

[0054] In the present application, the alkaline washing treatment time is 10 min-2 h, preferably 0.5-1 h.

[0055] In the present application, the liquid-solid ratio of the alkaline washing solution to the zinc substrate is 1-50 ml / g, preferably 10-30 ml / g.

[0056] In the present application, the alkaline washing removes the organic residues on the surface of the commercially available zinc foil, providing a basis for subsequent etching treatment.

[0057] In the present application, the acid treatment solution (etching solution) comprises an inorganic acid, an inhibitor, and ultrapure water. The inorganic acid is one of sulfuric acid, hydrochloric acid, and nitric acid. The inhibitor is one of sodium p-toluenesulfonate, sodium thiocyanate, and aniline. The ultrapure water has a resistivity of >18 MΩ / cm.

[0058] In the present application, the concentration of the inorganic acid in the etching solution is 0.1-0.5 mol / l, preferably 0.3-0.4 mol / l. The concentration of the inhibitor is 1 wt‰-10 wt‰, preferably 2.5 wt‰-5 wt‰.

[0059] In the present application, the soaking time is 0.5 h-3 h, preferably 1.25-2 h.

[0060] In the present application, the liquid-solid ratio of the etching solution to the zinc substrate is 10-100 ml / g, preferably 20-50 ml / g.

[0061] In the present application, a coating layer comprising Formula A can be coated on the zinc substrate based on a conventional coating process. The steps are, for example, dispersing Formula A and a binder (such as PVDF and styrene-butadiene rubber) in a solvent such as NMP, then applying a coating knife to coat on the treated zinc foil and drying, so that the zinc foil surface is coated with the modified coating layer.

[0062] The PVDF has a molecular weight of 500,000-1,500,000, and further can be 750,000-1,100,000. The solid content of the SBR emulsion is 45%-53%, preferably 48%-50%; the viscosity is 40 mPa S-300 mPa S, preferably 50 mPa S-250 mPa S. The purity of NMP is greater than 99.8%.

[0063] In the present application, the mass ratio of formula 1, PVDF and SBR is 72wt%-76wt%, 13wt%-16wt% and 8wt%-15wt% respectively. Preferably, it is 74wt%-75wt%, 14wt%-15wt% and 14wt%-15wt%.

[0064] In the present application, formula 1, PVDF and SBR are put into a tank containing NMP, and the solid content is 8%-20%, preferably 12%-16%. The slurry temperature is maintained at 45°C-65°C during the dispersion process, preferably 50°C-55°C. The dispersion time is 3h-5h, preferably 4h-4.5h. The rotation speed of the dispersion machine is 800rpm-1100rpm, preferably 950rpm-1000rpm.

[0065] In the present application, the uniformly dispersed slurry is vacuum defoamed, and stirring is assisted during the defoaming process. The vacuum degree during the vacuum defoaming operation is-70Kpa--100Kpa, preferably-80Kpa--90Kpa. The vacuum tank temperature is 20°C-40°C, preferably 25°C-30°C. The stirring speed is 1000rpm-1300rpm, preferably 1190rpm-1250rpm. The stirring time is 0.5h-1.5h, preferably 0.75h-1h.

[0066] In the present application, the defoamed slurry is filled with pure argon in a sealed low-temperature storage tank. The internal pressure of the tank is 200Kpa-350Kpa, preferably 270Kpa-320Kpa. The low-temperature temperature is-10°C--20°C, preferably-15°C--18°C.

[0067] In the present application, when performing coating operation, the environmental humidity and temperature are 5%rh-15%rh and 20°C-30°C respectively, preferably 8%rh-12%rh and 25°C-28°C.

[0068] In the present application, the ratio of the volume of the slurry to the area of the zinc substrate is 0.02ml / cm 2 -0.06ml / cm 2 , preferably 0.027ml / cm 2 -0.04ml / cm 2 .

[0069] In the present application, the coating speed and the coating thickness are 0.5 cm / s-1.25 cm / s and 45 μm-55 μm, respectively, and preferably 0.75 cm / s-1 cm / s and 50 μm-52.5 μm, respectively.

[0070] In the present application, after the coating, the pole piece is transferred to a vacuum oven. The vacuum degree and the temperature are-98 Kpa--100.5 Kpa and 30°C-40°C, respectively, and preferably-99 Kpa--100 Kpa and 32°C-35°C, respectively. The drying time is 0.5 h-1 h, and preferably 0.6 h-0.75 h.

[0071] In the present application, after the coating step, a post-treatment is performed, which is beneficial to the stable linkage of the coating material and the substrate material, and can improve the high discharge depth and the electrochemical stability of the prepared material under large current density.

[0072] In the present application, the mechanical pressure is a roller pressing treatment. The roller pressure, the linear speed and the roller temperature are 50 Mpa-125 Mpa, 0.4 m / min-0.7 m / min and 50°C-80°C, respectively, and preferably 80 Mpa-95 Mpa, 0.5 m / min-0.6 m / min and 60°C-70°C, respectively. The pole piece is sent into the roller press and rolled once in the same direction.

[0073] In the present application, the pole piece after the mechanical roller pressing is subjected to a heat treatment to strengthen the linkage of the coating and the zinc substrate. The atmosphere of the heat treatment process is one of argon, nitrogen and helium.

[0074] Preferably, the temperature of the heat treatment process is 60-160°C, and further preferably 80-150°C; the temperature rising rate is 1°C / min-5°C / min, and preferably 1.25°C / min-3°C / min; research shows that under the preferred conditions, the process and parameter synergy can be further improved, and the performance of the prepared material can be further improved.

[0075] The heat treatment time is 2 h or more, and considering the effect and preparation efficiency, it is further 4-7 h, and more further 3-5 h.

[0076] The modified coating thickness is 2-4 μm;

[0077] In the present application, the modified coating can be selectively subjected to an electrochemical zinc deposition treatment. For example, the pole piece coated with the modified coating can be inserted into a zinc ion electrolyte as a cathode together with a graphite anode to perform an electrodeposition treatment.

[0078] In the present application, the electrolyte can be, for example, a zinc sulfate solution, and the solute concentration thereof can be 1 mol / l-6 mol / l, and preferably 2 mol / l-4.5 mol / l. The current density in the electrodeposition stage is 1 mA / cm2 ~5mA / cm 2 , preferably 2mA / cm 2 ~4.1mA / cm 2 The relative distance between the two electrodes is 3cm~10cm, preferably 5cm~7.5cm. The electrodeposition time is 0.5h~2h, preferably 1h~1.25h.

[0079] The application also provides the application of the zinc negative electrode with the organic-inorganic hybrid multifunctional coating as a negative active material to prepare a water-based zinc ion battery.

[0080] In the application, the material prepared by the application can be used as a negative active material, and the required zinc ion battery and its components can be prepared based on known processes and principles.

[0081] The following is a typical case:

[0082] Example 1:

[0083] ①Take 100ml of 2mol / l sodium carbonate aqueous solution, take 5g of ultra-pure zinc foil with a thickness of 10μm and immerse it in the alkali solution, control the environmental temperature to be 30℃, soak for 0.75h, and then clean with pure water and anhydrous ethanol, and dry in an oven.

[0084] Take 125ml of 0.35mol / l HCl and 3wt‰ aniline aqueous solution (etching solution, aniline concentration based on the weight of the acid solution), immerse the alkali-washed zinc foil in the etching solution, control the environmental temperature to be 30℃, soak for 1.5h, and then clean with pure water and anhydrous ethanol, and dry in an oven to obtain a zinc substrate (modified zinc substrate).

[0085] ②Take 2.1g of formula A (in this case, formula 1-A, ), 1 million PVDF powder and SBR emulsion with a solid content of 50% and a viscosity of 150mPa S, and 20ml of NMP with a purity of 99.9% (the weight ratio of formula A, PVDF and SBR is 75:12.5:12.5). Put them in a stainless steel tank. Keep the environmental temperature at 50℃, adjust the disperser speed to 1000rpm and disperse for 4h.

[0086] ③Take the slurry of step ② and place it in a vacuum box. Keep the vacuum box temperature at 27℃, and vacuum to-85Kpa. The stirring speed is 1200rpm, and the stirring time is 0.8h. After defoaming, pure argon is injected into the stainless steel tank, and the internal pressure of the tank is adjusted to 300Kpa. After sealing the tank, it is transferred to a-16℃ refrigerator for low-temperature storage.

[0087] (4) Put the zinc substrate of step (1) and the slurry of step (3) on a wire bar coater, and keep the humidity and temperature at 10% rh and 26°C, respectively. The volume of the slurry and the area of the zinc substrate are 0.03 ml / cm 2 . The coating rate and thickness of the coater are set at 0.6 cm / s and 50 μm, respectively. After coating, the electrode is transferred to a vacuum oven, and the vacuum degree and temperature are set at -95 Kpa and 33°C, respectively. The electrode is dried for 0.7 h.

[0088] (5) Put the product of step (4) into a roll press, and adjust the roll pressure, linear speed, and roll temperature to 90 Mpa, 0.55 m / min, and 65°C, respectively.

[0089] (6) Put the product of step (5) into a tube furnace, and heat it to 100°C at a rate of 2°C / min in an argon atmosphere. After 3.5 h, the product is naturally cooled to room temperature to obtain the ultrathin zinc electrode with the coating of formula 1.

[0090] (7) Put the product of step (6) into an electrolytic cell, and use a zinc sulfate electrolyte with a concentration of 3 mol / l and a current density of 3 mA / cm 2 . The distance between the two electrodes is 7 cm. After 1 h of deposition, the product is washed with ultrapure water and anhydrous ethanol and dried to obtain the zinc negative electrode with the organic-inorganic hybrid multifunctional coating.

[0091] Half-cell assembly and performance determination:

[0092] A CR2025 button cell is assembled in the following order: zinc electrode, glass fiber separator, zinc electrode, and foam nickel. A zinc ion battery electrolyte containing 2 mol / l zinc sulfate is added, and the cell is sealed using a battery sealing machine. The assembled symmetric cell is tested for charge and discharge at 25°C at a current density of 1 mA / cm 2 , a surface capacity of 1 mAh / cm 2 , a current density of 5 mA / cm 2 , and a surface capacity of 5 mAh / cm 2 . The test instrument is a blue electric chemical measurement system.

[0093] Example 2:

[0094] Compared with Example 1, the only difference is that the conditions of step (1) are changed, and the other operations and parameters are the same as those of Example 1. The experimental groups are as follows:

[0095] Group A: change the concentration of alkali solution to 1.5 mol / l, the treatment time under alkali solution is 0.5 h; the acid in etching solution is sulfuric acid, the concentration of which is 0.3 mol / l; the corrosion inhibitor is sodium p-toluenesulfonate, and the concentration thereof is 5 wt‰, the acid treatment time is 1.25 h, and other conditions are the same as in Example 1.

[0096] B: no aniline is added in the etching solution, and other conditions are the same as in Example 1.

[0097] Example 3:

[0098] Compared with Example 1, the only difference is that the binder in step 2 is changed, and other operations and parameters are the same as in Example 1, and the experimental groups are as follows:

[0099] Group A: the binder is PVDF, and the weight of formula A and the binder is the same as in Example 1.

[0100] Group B: the binder is SBR, and the weight of formula A and the binder is the same as in Example 1.

[0101] Other conditions are the same as in Example 1.

[0102] Example 4:

[0103] Compared with Example 1, the only difference is that the binder in step 2 is changed, and other operations and parameters are the same as in Example 1, and the experimental groups are as follows:

[0104] Group A: the binder is PVDF, and the weight of formula A and the binder is the same as in Example 1.

[0105] Group B: the binder is SBR, and the weight of formula A and the binder is the same as in Example 1.

[0106] Group C: the ratio of formula A, PVDF and SBR is changed to 80:10:10.

[0107] Other operations and parameters are the same as in Example 1.

[0108] Example 5:

[0109] Compared with Example 1, the only difference is that steps 5 and 6 are not performed, and the pole piece in step 4 is directly subjected to the treatment in step 7, and other operations and parameters are the same as in Example 1.

[0110] Example 6

[0111] Compared with Example 1, the only difference is that step 7 is not performed, and other operations and parameters are the same as in Example 1.

[0112] Example 7

[0113] Compared with Example 1, the only difference is that the current density for electrodeposition in step 7 is changed to 2.5 mA / cm2， The electrodeposition time was 1.25 h. Other operations and parameters were the same as in Example 1.

[0114] Comparative Example 1

[0115] Comparative Example 1 except that in Step 2, no Formula A was added, and other operations and parameters were the same as in Example 1.

[0116] Comparative Example 2

[0117] Comparative Example 1 except that in Step 2, Formula A was replaced by , and other operations and parameters were the same as in Example 1.

[0118] Comparative Example 3

[0119] Comparative Example 1 except that in Step 2, no Formula A was added, and the amount of Formula A was added in the electrolyte of Step 7, and other operations and parameters were the same as in Example 1.

[0120] Comparative Example 4

[0121] Comparative Example 1 except that Steps 2-6 were omitted, the electrode was directly subjected to the treatment of Step 7, and Formula A was added in the electrolyte of Step 7 (the amount of Formula A and other operations were the same as in Example 1.

[0122] Table 1: Test results of Examples and Comparative Examples at a current density of 1 mA / cm 2 and a surface capacity of 1 mAh / cm 2

[0123] Material Cycle life (h) Polarization voltage (mV) Example 1 2438 30 Example 2A 2215 32 Example 2B 967 39 Example 3A 1135 153 Example 3B 420 66 Example 4A 325 61 Example 4B 398 52 Example 4C 2321 33 Example 5 962 63 Example 6 224 109 Example 7 2309 36 Comparative Example 1 60 190 Comparative Example 2 130 169 Comparative Example 3 43 223 Comparative Example 4 27 168

[0124] Table 2: Test results of Examples and Comparative Examples at a current density of 5 mA / cm 2 and a surface capacity of 5 mAh / cm 2

[0125] Material Cycle life (h) Polarization voltage (mV) Example 1 310 82 Example 2A 281 88 Example 2B 127 106 Example 3A 133 304 Example 3B 62 193 Example 4A 47 172 Example 4B 51 148 Example 4C 267 87 Example 5 129 166 Example 6 30 295 Example 7 275 88 Comparative Example 1 7 422 Comparative Example 2 15 369 Comparative Example 3 5 461 Comparative Example 4 19 374

[0126] In Table 1, the cycle life refers to the cycle time when the battery is short-circuited.

[0127] From the Examples and Comparative Examples, it can be seen that the functional coating layer having the structure of Formula A is innovatively coated on the surface of a zinc substrate, and the functional coating layer has excellent stability and a fast zinc ion conduction rate, and can exhibit excellent stability at a high discharge depth and a large current density.

[0128] ​​In addition, it can be known from Examples 1 and 2 that the performance of the zinc negative electrode prepared subsequently can be improved by adding a certain corrosion inhibitor in the acid solution. It can be known from Examples 1 and 3 that the discharge depth and stability under large current of the zinc negative electrode can be unexpectedly and significantly improved by controlling the substituent of Formula A, in particular, by selecting Formula 1-A. It can also be known from Examples 1 and 4 that the discharge depth and large current performance of the prepared zinc negative electrode can be improved by using the combined binder. It can also be known from Examples 1 / 6-7 that the cycle stability of the material under high discharge depth and large current can be significantly improved by pre-zinc-embedding treatment of the zinc negative electrode.

Claims

1. A modified zinc anode, characterized in that, It includes a zinc substrate and a modified coating compounded thereon on its surface; the modified coating includes an adhesive and a modifier of formula A; Formula A In Formula A, R1 to R5 are individually H, alkyl, hydroxyl, alkoxy, carboxyl, nitro, trifluoromethyl, or halogen, wherein R1 to R5 are not all H at the same time; R6 is H, Na, K, or NH4.

2. The modified zinc anode as described in claim 1, characterized in that, The zinc substrate is zinc foil.

3. The modified zinc anode as described in claim 2, characterized in that, The thickness of the zinc substrate is 5~15μm.

4. The modified zinc anode as described in claim 2, characterized in that, The zinc substrate is a zinc substrate that has been modified by alkali solution and acid solution in sequence.

5. The modified zinc anode as described in claim 1, characterized in that, In Formula A, R1, R4, and R5 are H, and R2 and R3 are individually hydroxyl, carboxyl, or alkoxy groups.

6. The modified zinc anode as described in claim 5, characterized in that, R3 is a C1-C6 alkoxy group, and R2 is a hydroxyl group.

7. The modified zinc anode as described in claim 1, characterized in that, The adhesive includes at least one of PVDF, SBR, and CMC.

8. The modified zinc anode as described in claim 7, characterized in that, The adhesive is PVDF and SBR in a weight ratio of 1:0.5~2.

9. The modified zinc anode as described in claim 1, characterized in that, In the modified coating, the content of formula A is 70~80wt%.

10. The modified zinc anode according to any one of claims 1 to 9, characterized in that, The modified coating also includes zinc metal embedded by electrochemical deposition.

11. The modified zinc anode as described in claim 10, characterized in that, The zinc metal inlay is 5~10 mg / cm³. 2 .

12. The modified zinc anode as described in claim 11, characterized in that, The zinc metal inlay is 6 mg / cm³. 2 ~8 mg / cm 2 .

13. A method for preparing a modified zinc anode according to any one of claims 1 to 12, characterized in that, Formula A and the binder are slurried with a solvent to obtain a slurry, which is then coated on the surface of a zinc substrate and dried to obtain a modified negative electrode with a modified coating on the surface.

14. The method for preparing the modified zinc anode as described in claim 13, characterized in that, The zinc substrate is a zinc substrate that has been modified by alkali solution and acid solution in sequence.

15. The method for preparing the modified zinc anode as described in claim 14, characterized in that, The alkaline solution is an aqueous solution containing one of the following alkaline solutes: sodium carbonate, sodium bicarbonate, sodium phosphate, and disodium hydrogen phosphate.

16. The method for preparing the modified zinc anode as described in claim 15, characterized in that, The concentration of the alkaline solute is 1~3 mol / L; the treatment time with alkaline solution is 10 min~2 h.

17. The method for preparing the modified zinc anode as described in claim 16, characterized in that, The concentration of the alkaline solute is 1.5~2.4 mol / L; the treatment time with alkaline solution is 0.5~1 h.

18. The method for preparing the modified zinc anode as described in claim 14, characterized in that, The acid solution is an aqueous solution containing at least one acidic component from hydrochloric acid and sulfuric acid; The concentration of the acidic component is 0.1~0.5 mol / L.

19. The method for preparing the modified zinc anode as described in claim 18, characterized in that, Corrosion inhibitors are also added to the acid solution; The corrosion inhibitor includes at least one of sodium toluenesulfonate, sodium thiocyanate, and aniline; The content of corrosion inhibitor in the acid solution is 1 wt‰ to 10 wt‰; The acid treatment time is 0.5 h to 3 h.

20. The method for preparing the modified zinc anode as described in claim 19, characterized in that, The content of corrosion inhibitor in the acid solution is 2.5 wt‰~5 wt‰; The acid treatment time is 1.25~2 h.

21. The method for preparing the modified zinc anode as described in claim 14, characterized in that, After acid treatment, the zinc substrate is obtained by washing with water, washing with organic solvent, and drying.

22. The method for preparing the modified zinc anode as described in claim 13, characterized in that, The solvent includes at least one of NMP and DMF.

23. The method for preparing the modified zinc anode as described in claim 22, characterized in that, The dried electrode sheets are then subjected to rolling and / or heat treatment.

24. The method for preparing the modified zinc anode according to any one of claims 13 to 23, characterized in that, A modified zinc anode with a modified coating on its surface is used as the anode and graphite as the anode. Electrodeposition is performed in an electrolyte containing zinc ions to electrochemically deposit zinc in the modified coating, thereby obtaining the modified zinc anode with zinc embedded in the modified coating.

25. The method for preparing the modified zinc anode as described in claim 24, characterized in that, The current density during the electrodeposition stage is 1 mA / cm². 2 ~ 5 mA / cm 2 .

26. The method for preparing the modified zinc anode as described in claim 25, characterized in that, The current density during the electrodeposition stage is 2 mA / cm². 2 ~ 4.1 mA / cm 2 .

27. The method for preparing the modified zinc anode as described in claim 24, characterized in that, The electrodeposition time is 0.5 h to 2 h.

28. The method for preparing the modified zinc anode as described in claim 27, characterized in that, The electrodeposition time is 1 h to 1.25 h.

29. The application of a modified zinc anode according to any one of claims 1-12 or a modified zinc anode prepared by the preparation method according to any one of claims 13-28, characterized in that, It was used as the negative electrode in the preparation of aqueous zinc-ion batteries.

30. An aqueous zinc-ion battery, characterized in that, It includes the modified zinc anode according to any one of claims 1 to 12 or the modified zinc anode prepared by the preparation method according to any one of claims 13 to 28.

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