Method for in-situ construction of zinc negative electrode interface protection layer based on gel slow release technology

Abstract

The invention discloses a method for in-situ construction of a zinc negative electrode interface protection layer based on a gel slow release technology. The method comprises the following steps: uniformly coating the surface of a zinc foil with a gel solution which contains gel polymerization and is distributed by a slow release component, and finally obtaining the zinc foil with the interface protection layer. According to the method disclosed by the invention, the reaction rate and the reaction uniformity when the slow-release component and zinc react to form the interface layer are controlled through the gel network, so that compared with the prior art that a passivation layer can only be temporarily removed by means of polishing or acid pickling, and a new passivation layer can be formed in a battery circulation process, the method has the advantages that the service life is prolonged; according to the scheme, the oxidation passivation layer on the zinc metal surface can be effectively removed, a new passivation layer is prevented from being formed, and the method has remarkable advantages.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc battery negative electrode treatment, and specifically relates to a method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology. Background Art

[0002] A significant advantage of aqueous zinc batteries is the direct use of zinc metal as the negative electrode. Zinc metal negative electrodes have high energy density, easy recycling and less processing requirements, which are more advantageous than ion host negative electrodes. However, due to the uneven deposition of zinc, dendrites are generated during the cycle, which will eventually lead to soft short circuits or even direct battery failure, affecting the stability and life of the battery.

[0003] The deposition of zinc is affected by many factors. Studies involve the composition and solvent structure of the electrolyte, electrochemical parameters such as current density, and environmental factors such as temperature and pressure. Most importantly, the nature of the substrate plays a crucial role. The zinc surface should have a smooth morphology to avoid the influence of the "tip effect" and should promote the rapid diffusion of zinc ions to avoid dendrite formation caused by local ion enrichment. For zinc metal stored in an air environment, it is necessary to remove the intrinsic oxide layer because these passivation layer components hinder the transport of zinc ions and lead to uneven zinc deposition. In addition, zinc deposition occurs preferentially at damaged sites of the passivation layer, and local zinc deposition leads to dendrite growth. Studies have shown that physically polished or acid-etched zinc metal performs better than untreated zinc.

[0004] Physical polishing is to polish the surface of commercial zinc foil by using sandpaper or other mechanical methods. However, a large number of textures will be produced on the polished surface. For the microscopic scale of zinc ion deposition, the uneven morphology is easy to cause dendrite growth, which increases the specific surface area of ​​zinc and introduces a large number of defects, resulting in aggravated side reactions in subsequent cycles. Moreover, the polishing process only temporarily removes the passivation layer, and the surface is easily oxidized again after being exposed to the atmosphere for a period of time.

[0005] Chemical acid etching is to immerse the zinc foil in an acidic solution (such as phosphoric acid, sulfuric acid, etc.), corrode the surface with acid, remove the passivation layer and expose the active zinc surface; however, the acid etching process reacts too fast, and there is a preferential orientation of the reaction crystal plane. After the reaction, a large number of holes will be generated, making it difficult to control the surface morphology to be smooth; a large number of bubbles will be generated during the acid etching process, which will interfere with the surface reaction and cause local unevenness; and acid etching increases the surface area of ​​zinc, which may lead to the intensification of side reactions (such as hydrogen evolution reaction).

[0006] That is, the polishing or pickling methods in the prior art can only temporarily remove the passivation layer, and a new passivation layer, such as zinc oxide and zinc hydroxysulfate, will be formed during the battery cycle. Therefore, it is crucial and challenging to remove the oxidized passivation layer on the surface of zinc metal and prevent the formation of a new passivation layer. Summary of the invention

[0007] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0008] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0009] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0011] The hydrogel polymer is dissolved in deionized water, heated and stirred until the hydrogel polymer is completely dissolved, and after cooling to room temperature, a sustained-release component is added and stirred until uniform to obtain a gel solution, wherein the sustained-release component is an acid or a substance that can form a zinc-like protective layer through a chemical conversion reaction;

[0012] The gel solution is evenly coated on the clean zinc foil surface to ensure that the gel is completely covered and the thickness is uniform. The coated zinc foil is allowed to react at room temperature to form a uniform pretreatment coating on the zinc substrate.

[0013] The excess gel on the upper layer of the pretreatment coating that does not contact the zinc substrate is scraped off, and the residual gel is removed by rinsing with deionized water. Finally, the zinc foil is rinsed with anhydrous ethanol and dried naturally at room temperature to obtain a zinc foil with an interface protective layer.

[0014] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the hydrogel polymer comprises one of polyvinyl alcohol, alginate, chitosan, gelatin and polyethylene glycol.

[0015] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the heating and stirring temperature is 60 to 95° C. and the time is 2 to 4 hours.

[0016] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the heating and stirring temperature is 60 to 95° C. and the time is 2 to 4 hours.

[0017] As a preferred solution of the method for in-situ construction of zinc negative electrode interface protection layer based on gel sustained release technology of the present invention, wherein: the mass concentration of hydrogel polymer in the gel solution is 5-20%.

[0018] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology described in the present invention, the acid comprises one of phosphoric acid, hydrochloric acid, boric acid, formic acid, acetic acid, citric acid, and tartaric acid.

[0019] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protective layer based on gel sustained-release technology described in the present invention, the substance capable of forming a zinc-like protective layer through a chemical conversion reaction comprises one of chromates, fluorides, and phosphates.

[0020] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the concentration of the acid in the gel solution is 0.1-3M.

[0021] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the thickness of the gel coated on the surface of the zinc foil is 0.1 to 1 cm.

[0022] As a preferred embodiment of the method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology of the present invention, the static reaction time is 1 to 4 hours.

[0023] Another object of the present invention is to provide a method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology, and to use the zinc foil as a zinc negative electrode in the preparation of a zinc battery.

[0024] Beneficial effects of the present invention:

[0025] The method of in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology in the present application can eliminate surface defects introduced by physical polishing, overcome the problems of overly rapid reaction and uneven surface corrosion in chemical acid etching, provide a uniform and stable zinc negative electrode surface, and inhibit dendrite growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0027] Figure 1 Flow chart for in-situ construction of zinc negative electrode interface protection layer based on gel sustained release technology (GSR);

[0028] Figure 2 This is a morphology picture of the gel sustained-release pretreatment coating on the zinc foil after treatment in Example 1.

[0029] Figure 3 Spectral characterization diagram of the zinc foil treated in Example 1 and the untreated zinc foil.

[0030] Figure 4 This is the EDS element distribution diagram of the cross section of the zinc foil after treatment in Example 1.

[0031] Figure 5 This is a schematic diagram of the process of processing zinc foil by traditional physical polishing method in comparative example 1.

[0032] Figure 6 This is a schematic diagram of the process of treating zinc foil by traditional chemical acid etching method in comparative example 2.

[0033] Figure 7 The scanning electron microscope images are of the zinc foils treated in Example 1 and Comparative Examples 1 and 2 and the untreated zinc foil.

[0034] Figure 8 SEM image and digital photograph of the zinc electrode after cycling (inset).

[0035] Fig. 9 For zinc at a current density of 1 mA cm -2 In-situ optical microscope cross-sectional photograph during deposition for 1 hour under the same conditions.

[0036] Fig.10 LSV curves of different zinc negative electrodes in 0.5M Na2SO4 electrolyte.

[0037] Fig.11 Long-cycle performance of zinc symmetric batteries with different zinc anode compositions.

[0038] Fig.12 These are SEM images and digital photos of the zinc surfaces after different acid treatments in Example 2 and Comparative Example 3.

[0039] Fig.13 The long cycle stability test results of symmetrical batteries assembled with zinc foils obtained after different acid treatments in Example 2 and Comparative Example 3.

[0040] Fig.14 The SEM images of the surface and cross section of the zinc foil after the product of Example 3 was treated for 9 hours.

[0041] Fig.15 These are SEM images of the zinc surface after different phosphoric acid concentrations and treatment times in Example 4. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] Unless otherwise specified, the raw materials used in the present invention are all commercially available in the art.

[0046] Example 1

[0047] Reference Figure 1 This embodiment provides a method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained release technology (GSR), specifically:

[0048] 1) Clean the zinc foil with anhydrous ethanol to remove dust and oil on the surface, ensure the base is clean, and obtain a clean zinc foil;

[0049] 2) polyvinyl alcohol (PVA) was mixed with deionized water to obtain a PVA aqueous solution with a PVA mass fraction of 15%, heated to 90° C., stirred for 2 hours until the PVA was completely dissolved, cooled to room temperature, and then 1 M phosphoric acid (sustained-release component) was added and stirred for more than 24 hours until the solution was uniform, to obtain a gel solution;

[0050] 3) uniformly coating the gel solution on the surface of a clean zinc foil, adjusting the gel coating thickness to 0.5 cm by scraping, ensuring that the gel is completely covered and the thickness is uniform, and allowing the coated zinc foil to stand for reaction at room temperature for 1 hour to allow the slow-release component to slowly react with the zinc substrate to form a uniform pretreatment coating on the zinc substrate;

[0051] 4) Use a scraper to scrape off the excess gel on the upper layer of the pretreatment coating that does not contact the zinc substrate, rinse with deionized water to remove the residual gel, and finally rinse the zinc foil with anhydrous ethanol and dry it naturally at room temperature (humidity ≤ 60%) to obtain a zinc foil (GSR-Zn) with an interface protective layer.

[0052] Figure 2 The morphology of the gel sustained-release pretreatment coating of the zinc foil after treatment in Example 1, wherein (a) is a scanning electron microscope image, (b) is a 3D morphology restored by an atomic force microscope, and (c) is a cross-sectional image; Figure 3The spectroscopic characterizations of the treated zinc foil and the untreated zinc foil in Example 1, wherein (a) is the X-ray photoelectron spectroscopy P2p spectrum, and (b) is the Raman spectrum; Figure 4 The EDS element distribution diagram of the cross section of the zinc foil after the treatment in Example 1, wherein (a) is the cross section image; (b) is the O element distribution diagram; (c) is the P element distribution diagram; and (d) is the Zn element distribution diagram.

[0053] The P2p spectrum of X-ray photoelectron spectroscopy (XPS) further confirmed that phosphorus signals appeared on the zinc surface treated by the gel sustained release of this embodiment, proving that the gel sustained release was not a simple acid etching, but promoted the formation of a solid interface layer rich in zinc phosphate.

[0054] Through Raman spectroscopy, we can see that on the untreated zinc surface, there is an asymmetric vibration peak of carbonate. After gel slow-release pretreatment, the vibration peak of phosphate and CH bond appear on the surface. It proves that the gel slow-release pretreatment coating can effectively remove the surface passivation layer and form a composite coating of zinc phosphate inorganic components and polyvinyl alcohol organic components.

[0055] The EDS element distribution of the cross section was confirmed, and it can be clearly seen that the granular coating area is composed of three elements: Zn, P, and O. The space between the zinc phosphate particles is filled with O. This confirms that the coating is a composite coating composed of zinc phosphate particles and polyvinyl alcohol organic components.

[0056] Comparative Example 1

[0057] Reference Figure 5 In this comparative example, the zinc foil is processed by a traditional physical polishing method (Polished Zn), specifically:

[0058] 1) First, polish the clean zinc foil with 3000-grit metallographic sandpaper for 60 times;

[0059] 2) The zinc foil is then rinsed with anhydrous ethanol and dried naturally at room temperature (humidity ≤ 60%) to obtain the zinc foil treated in this comparative example.

[0060] Comparative Example 2

[0061] Reference Figure 6 In this comparative example, the zinc foil is treated by a conventional chemical acid etching method (Etched Zn), specifically:

[0062] 1) Clean the zinc foil with anhydrous ethanol to remove dust and oil on the surface, ensure the base is clean, and obtain a clean zinc foil;

[0063] 2) Soak the clean zinc foil in 1M phosphoric acid solution, let it stand for 1 hour, then rinse the zinc foil with deionized water and anhydrous ethanol respectively, and dry it naturally at room temperature (humidity ≤ 60%) to obtain the zinc foil treated in this comparative example.

[0064] Figure 7 Scanning electron microscope images of the zinc foil treated in Example 1 and Comparative Examples 1 and 2 and the untreated zinc foil, wherein (a, b) are untreated zinc; (c, d) are physically polished zinc; (e, f) are acid-etched zinc; and (g, h) are gel-sustaining treated zinc.

[0065] from Figure 7 It can be seen that compared with other treatment methods, the gel sustained-release treatment can evenly and gently remove the zinc surface passivation layer, keep the microscopic surface flat, and obtain a uniform and thin zinc phosphate-dominated passivation layer on the zinc surface. This is because the formed gel network uniformly forms reaction sites, limiting the reaction rate.

[0066] Electrochemical testing

[0067] Zinc was punched into discs with a diameter of 12 mm, and a CR2025 battery was used as a mold. The specific battery assembly sequence was as follows: first, the negative electrode shell was placed at the bottom of the mold, and then the zinc sheet, glass fiber membrane, 2M ZnSO4 electrolyte, and zinc sheet were placed in sequence, followed by gaskets and shrapnel, and finally the positive electrode shell was placed and packaged to assemble the battery. The long cycle performance test of the battery was completed on a Blue Electric Battery Tester (CT3001A).

[0068] Figure 8 The SEM images of zinc electrodes after cycling, where (a) is untreated zinc (Raw Zn); (b) is GSR-treated zinc, and the inset is a macro photo of the electrode. The SEM image clearly shows the contrast between the two after 100 cycles. In the microscopic area, untreated zinc tends to generate uncertain and randomly distributed zinc dendrites due to the presence of a passivation layer. The inset shows the deposition in a larger macroscopic area, and it can be intuitively seen that some of these areas will have excessive zinc deposition, while the rest remain flat. In contrast, after removing the passivation layer, the GSR-treated zinc also forms a composite coating with a high zinc ion diffusion coefficient, which can effectively regulate zinc deposition and maintain more uniform reactivity in the electrode area.

[0069] Fig. 9 For zinc at a current density of 1 mA cm -2 In-situ optical microscope cross-sectional photographs of the zinc deposited under 1 hour conditions, where (a) is untreated zinc and (b) is GSR-treated zinc. Fig. 9It can be seen that for untreated zinc, the growth of zinc dendrites is obvious. Due to the presence of the passivation layer, untreated zinc leads to local deposition of zinc and dendrite growth. In addition, untreated zinc will preferentially deposit zinc on the cross section because the cut cross section is a newly exposed active site. At the same time, during the test, bubbles will continue to precipitate on the surface of untreated zinc, indicating that the HER reaction on the electrode surface is more significant. In stark contrast, GSR-treated zinc can effectively regulate zinc deposition because of the zinc phosphate-dominated interface layer, and exhibits a relatively uniform morphology during zinc deposition.

[0070] The linear sweep voltammetry (LSV) was used to test the starting potential of the hydrogen evolution reaction (HER) for zinc treated by different methods in Example 1 and Comparative Examples 1 and 2. The test was carried out in 0.5M Na2SO4 to avoid the interference of Zn deposition on the HER test. The results are as follows: Fig.10 , Fig.11 shown.

[0071] from Fig.10 It can be seen from the LSV curve that the reaction starting potential of HER on the GSR-Zn surface is significantly delayed compared with that of Raw Zn, indicating that GSR-treated zinc can achieve anti-corrosion protection and inhibit the occurrence of HER side reactions.

[0072] Fig.11 The long cycle performance of the zinc symmetric battery with a current density and capacity of 0.5 mA cm -2 and 0.5mAhcm -2 In the long cycle test, the untreated zinc pierced the diaphragm due to local dendrite growth, resulting in a short circuit, which in turn caused the battery to fail in 136 hours. Due to the violent hydrogen evolution reaction, the cycle life of the polished zinc was 109 hours, which was reduced compared to the untreated zinc. The etched zinc improved in cycle life compared to the untreated zinc because a large number of holes were produced by acid etching, providing space for zinc deposition. However, it eventually failed around 1250 hours due to uneven zinc deposition and side reactions. GSR-treated zinc exhibited the longest cycle life of up to 5200 hours by uniformly removing the surface passivation layer and constructing an artificial interface layer to achieve fast zinc ion conduction.

[0073] Example 2

[0074] This embodiment uses different types of sustained-release components for comparative experiments. Specifically, the difference from Embodiment 1 is that the phosphoric acid in step 2) is adjusted to sulfuric acid (H2SO4), benzenesulfonic acid (BA), trifluoromethanesulfonic acid (HOTf) and nitric acid (HNO3);

[0075] The remaining steps and processes are all referred to Example 1, until the zinc foil treated with different slow-release components in this example.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 2 is that the acid etching solutions are adjusted to sulfuric acid (H2SO4), benzenesulfonic acid (BA), trifluoromethanesulfonic acid (HOTf) and nitric acid (HNO3);

[0078] The remaining steps and processes are all referred to Comparative Example 2, except for the zinc foil etched by different acid solutions in this comparative example.

[0079] Fig.12 The SEM images and digital photos of the zinc surface after different acid treatments in Example 2 and Comparative Example 3, where (a, e) H2SO4; (b, f) HOTF; (c, g) BA; (d, h) HNO3. (ad) is acid solution etching, and (eh) is GSR treatment. It can be seen that even with the same acid solution, the samples etched with aqueous solutions of sulfuric acid, benzenesulfonic acid and trifluoromethanesulfonic acid (show uneven corrosion pits, while the samples treated with nitric acid solution form a thick needle-shaped hydroxy zinc nitrate crystal layer. In contrast, the uniformity of the interface reaction between the acid and zinc can be effectively adjusted by the corresponding GSR treatment. It can be clearly seen from the SEM image that the GSR-treated samples show a smooth surface. This will help zinc reduce the "needle tip effect" and inhibit dendrite growth.

[0080] Fig.13 The long cycle stability test results of the zinc foil assembled into a symmetrical battery are shown. It can be seen that all GSR-treated zinc have significantly longer symmetrical battery cycle life than the samples treated with the corresponding acid aqueous solution. Among them, the zinc treated with sulfuric acid GSR can be stably cycled for 881 hours, while the sample etched with sulfuric acid aqueous solution failed after 383 hours of cycling. The sample treated with trifluoromethanesulfonic acid GSR can be stably cycled for 3471 hours, while the corresponding aqueous solution etched sample can only be cycled for 1460 hours. The sample treated with benzenesulfonic acid GSR can be stably cycled for 2794 hours, while its aqueous solution etched sample can only fail after 846 hours of cycling. The sample treated with benzenesulfonic acid GSR can be stably cycled for 2691 hours, while its aqueous solution treated sample can only fail after 736 hours of cycling. These results strongly prove that the GSR method is a simple and versatile strategy that can effectively enhance the stability of zinc electrodes and is easy to expand.

[0081] Example 3

[0082] This example is used to explore the effect of different polyvinyl alcohol (PVA) concentrations on the treatment effect of zinc foil, specifically:

[0083] The difference from Example 1 is that the concentrations of the PVA aqueous solution in step 2) are adjusted to 0% PVA, 15% PVA and 20% PVA respectively, and the remaining steps and processes are all referred to Example 1 to obtain zinc foil treated with different PVA concentrations in this comparative example.

[0084] Fig.14 The morphology of the zinc foil surface and cross section after 9 hours of treatment, (a, d) are the surface and cross section of the zinc foil after 0% PVA treatment; (b, e) are the surface and cross section of the zinc foil after 15% PVA treatment; (c, f) are the surface and cross section of the zinc foil after 20% PVA treatment. It can be seen that the zinc surface after 9 hours of treatment with 0% PVA, i.e., aqueous solution, generates dense and hardened crystals. With the increase of PVA component, the crystallinity of zinc phosphate on the zinc surface gradually decreases, and the thickness of the crystal layer gradually decreases. This shows that the gel can control the reaction rate of phosphoric acid and zinc and refine the particles. At 20% PVA content, the surface coating becomes loose and porous, which may be because too much PVA during the treatment process seriously reduces the conduction of the phosphoric acid component. After considering the influence of the PVA component on the morphology and the operability and gel fluidity during the preparation process, we selected 15% PVA as the optimal content.

[0085] Example 4

[0086] This example is used to explore the effects of different concentrations of phosphoric acid as a slow-release component and treatment time on the treatment effect of zinc foil, specifically:

[0087] The difference from Example 1 is that the concentration of phosphoric acid in the gel solution in step 1) is adjusted to 0.1 M and 1 M respectively;

[0088] The reaction time of the coated zinc foil at room temperature in step 3) is 1, 4, and 8 hours respectively. The remaining steps are processed with reference to Example 1 to obtain zinc foils with different acid concentrations and treatment times in this comparative example.

[0089] Fig.15 The zinc surface morphology after different phosphoric acid concentrations and treatment time, among which (ac) were treated with 0.1M phosphoric acid for 1, 4 and 8 hours respectively; (df) were treated with 1M phosphoric acid for 1, 4 and 8 hours respectively. The results showed that within 4 hours, both phosphoric acid concentrations could form granular zinc phosphate products on the zinc surface. Regardless of the phosphoric acid concentration, the distribution of granular zinc phosphate is relatively uniform, proving the feasibility of the gel sustained release strategy.

[0090] When treated with 0.1M phosphoric acid for 1 hour and 4 hours, although the zinc phosphate was evenly distributed, it did not completely cover the zinc surface and could not form effective protection. However, the samples with 15% PVA, 1M phosphoric acid, and treatment time of 1 hour and 4 hours formed a uniformly covered surface coating.

[0091] In summary, the present invention provides a method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology, in which the reaction rate and reaction uniformity of the sustained-release component when reacting with zinc to form an interface layer are controlled by the gel network. Compared with the polishing or pickling means in the prior art which can only temporarily remove the passivation layer and form a new passivation layer during the battery cycle, the scheme of the present invention can effectively remove the oxidized passivation layer on the surface of the zinc metal and prevent the formation of a new passivation layer, which has significant advantages.

[0092] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention 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 invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology, characterized in that: include, The hydrogel polymer is dissolved in deionized water, heated and stirred until the hydrogel polymer is completely dissolved, and after cooling to room temperature, a sustained-release component is added and stirred until uniform to obtain a gel solution, wherein the sustained-release component is an acid or a substance that can form a zinc-like protective layer through a chemical conversion reaction; The gel solution is evenly coated on the clean zinc foil surface to ensure that the gel is completely covered and the thickness is uniform. The coated zinc foil is allowed to react at room temperature to form a uniform pretreatment coating on the zinc substrate. The excess gel on the upper layer of the pretreatment coating that does not contact the zinc substrate is scraped off, and the residual gel is removed by rinsing with deionized water. Finally, the zinc foil is rinsed with anhydrous ethanol and dried naturally at room temperature to obtain a zinc foil with an interface protective layer.

2. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The hydrogel polymer includes one of polyvinyl alcohol, alginate, chitosan, gelatin and polyethylene glycol.

3. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The heating and stirring is performed at a temperature of 60 to 95° C. and for a time of 2 to 4 hours.

4. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The mass concentration of the hydrogel polymer in the gel solution is 5-20%.

5. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The acid includes one of phosphoric acid, hydrochloric acid, boric acid, formic acid, acetic acid, citric acid and tartaric acid.

6. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The substance capable of forming a zinc-like protective layer through a chemical conversion reaction comprises one of chromate, fluoride salt and phosphate.

7. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 4, characterized in that: The acid concentration in the gel solution is 0.1-3M.

8. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The thickness of the gel coated on the surface of the zinc foil is 0.1-1 cm.

9. The method for in-situ construction of a zinc negative electrode interface protection layer based on gel sustained-release technology according to claim 1, characterized in that: The static reaction time is 1 to 4 hours.

10. Use of the zinc foil obtained by the method according to any one of claims 1 to 9 as a zinc negative electrode in the preparation of a zinc battery.

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