Zinc negative electrode protective film constructed by in-situ inorganic hybrid polymer and preparation method and application thereof

Abstract

The invention relates to the technical field of zinc ion batteries, and particularly discloses a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer as well as a preparation method and application of the zinc negative electrode protective film. The preparation method comprises the following steps: dissolving a high-molecular polymer to form a solution, adding a catecholamine compound and an inorganic metal salt solution into the solution to obtain a membrane casting solution, uniformly coating a zinc plate with the membrane casting solution, and removing a solvent. According to the invention, dopamine rich in catechol groups is introduced on the polymer by using inorganic metal ions, so that zinc ions can be induced to be uniformly deposited; meanwhile, dopamine hydrochloride and inorganic metal ions improve the surface effect of the polymer in the polymerization process, the overpotential of zinc ion deposition is reduced, and generation and growth of zinc dendrites are further inhibited. The modified electrode has super-long cycle stability and good capacity retention rate when being used for the water-based zinc ion battery, and a new strategy is provided for further improving energy storage and prolonging the service life of the zinc ion battery.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc ion batteries, and in particular relates to a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer, and a preparation method and application thereof. Background Art

[0002] With the continuous demand for renewable energy, zinc-ion batteries, as a new energy storage technology, have the advantages of high energy density, low cost, high safety, and environmental friendliness, and are widely used in the field of energy storage and mobile energy. However, in practical applications, there are many problems with the direct use of zinc metal anodes, which seriously hinder their large-scale application: zinc ion electrodeposition tends to be dendritic and uneven during charging and discharging, and dendrites are prone to pierce the diaphragm, causing internal short circuits in the battery, which seriously affects the battery's cycle performance and safety; in addition, hydrogen evolution reactions are prone to occur on the surface of the zinc anode and produce by-products, which will also reduce the battery's capacity and life. Therefore, how to protect the zinc anode has become one of the important ways to improve the stability and cycle life of zinc-ion batteries.

[0003] At present, common zinc negative electrode protection methods include coating protective films, adding chemical additives, etc. Chinese patent CN118969946 A discloses a method for preparing a zinc negative electrode protective layer with an affinity-repellent phase structure and its application, including dissolving an affinity-repellent phase block copolymer in ethanol / water to prepare a casting solution, and using a coating method to make the affinity-repellent phase block copolymer uniformly deposited on the zinc surface; using an affinity-repellent phase block copolymer as a protective layer for the zinc negative electrode, compared with directly using a bare zinc plate as the negative electrode of an aqueous zinc ion battery, the cycle stability of the battery is significantly improved. Although these methods have solved the above-mentioned zinc negative electrode problem to a certain extent, after the zinc negative electrode coated with the copolymer is subjected to a cycle test, the zinc crystals of the zinc negative electrode deposition layer do not show deposition on a specific crystal plane, which affects the electrochemical properties of the protective layer to a certain extent, which is not conducive to the further industrialization process of aqueous zinc ion batteries; and the capacity performance and cycle life of the aqueous zinc ion need to be further improved. Therefore, more effective measures must be taken to inhibit dendrite formation and growth and slow down the occurrence of side reactions, and further improve the capacity performance and cycle stability of zinc ion batteries, which is a technical problem that needs to be urgently solved in this field. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the purpose of the present invention is to propose a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer and a preparation method and application thereof. The zinc negative electrode coated with the protective film can more effectively inhibit the formation and growth of dendrites, and the obtained modified electrode is used in aqueous zinc ion batteries and has ultra-long cycle stability and good capacity retention rate.

[0005] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for preparing a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer, comprising the following steps: S1, dissolving the high molecular polymer to obtain a polymer solution; S2, uniformly mixing the catecholamine compound solution and the polymer solution described in step S1; S3, adding an inorganic metal ion salt having coordination ability to the mixed solution described in step S2 and stirring evenly to obtain a film casting solution; S4, uniformly coating the casting solution in step S3 on the surface of zinc metal, and obtaining the zinc negative electrode protective film after drying.

[0006] Preferably, the high molecular polymer in step S1 includes but is not limited to polyether, polyester, polyamide, polyurethane, polyetheramide block copolymer, chitosan and other polymers.

[0007] Further preferably, the polyetheramide block copolymer can be selected from commercial products, such as polyamide 6-polyethylene oxide block copolymer, polyamide 11-polyethylene oxide block copolymer, polyamide 12-polyethylene oxide block copolymer and other polyetheramide block copolymers.

[0008] More preferably, the polyether is polyoxyethylene.

[0009] Preferably, the concentration of the polymer solution in step S1 is 5-10 wt %.

[0010] Preferably, the catecholamine compound in step S2 is dopamine hydrochloride.

[0011] Further preferably, the concentration of the dopamine hydrochloride solution is 0.5-1 wt %.

[0012] The inorganic metal ion with coordination ability described in the present invention refers to the inorganic metal ion having good coordination ability. The present invention utilizes the inorganic metal ion with good coordination ability to cross-link with the polymer, and introduces dopamine rich in catechol groups on the polymer. The catechol groups have a stronger binding ability with zinc ions, and dopamine anchors the metal ions on the polymer chain through coordination to form uniformly distributed metal-organic composite sites. These sites, as nucleation centers for zinc ion deposition, can induce zinc ions to deposit more uniformly and avoid dendrite formation. At the same time, the metal ions form coordination bonds with the catechol groups of dopamine, enhancing the mechanical strength and stability of the polymer film. At the same time, the inorganic nano hybrid film generated in situ by polymerization of dopamine hydrochloride and inorganic metal ions can change the surface state of the polymer, effectively reduce the zinc deposition overpotential caused by the coverage of the protective film, and effectively inhibit the growth of zinc dendrites.

[0013] Preferably, the metal ion salt with coordination ability in step S3 is one of iron ion, manganese ion, chromium ion, aluminum ion salt, etc.; more preferably, it is a transition metal ion salt.

[0014] Further preferably, the iron ion salt can be selected from one of ferric chloride, ferric nitrate, ferric sulfate and the like.

[0015] Preferably, in the casting solution of step S3, the molar ratio of the inorganic metal ion salt to the catecholamine compound is 1:2-1:5, and the mass ratio of the polymer to the catecholamine compound is 10:1-15:1.

[0016] Preferably, the coating method in step S4 is any one of drip coating, blade coating, spin coating and spray coating, and after coating, the coating is dried at room temperature, the temperature is 15-30° C., and the drying time is 8-24 hours.

[0017] Preferably, the film thickness of the zinc negative electrode protective film in step S4 is ≤10 μm.

[0018] In a second aspect, the present invention provides a zinc negative electrode protective film material constructed by an in-situ inorganic hybrid polymer prepared by the above method.

[0019] In a third aspect, the present invention provides an application of the zinc negative electrode protective film constructed by the above-mentioned in-situ inorganic hybrid polymer in improving the capacity performance and cycle stability performance of aqueous zinc ion batteries.

[0020] In a fourth aspect, the present invention provides a negative electrode plate for a zinc ion battery, comprising a zinc negative electrode protective film constructed by the above-mentioned in-situ inorganic hybrid polymer.

[0021] In a fifth aspect, the present invention provides an aqueous zinc ion battery, comprising the above-mentioned zinc ion battery negative electrode sheet. The present invention uses an in-situ inorganic hybrid polymer film as a protective film for the zinc negative electrode, and the modified electrode has a high current density (10 mA / cm 2 、10mAh / cm 2 )'s symmetrical battery cycle performance far exceeds the cycle life of the current aqueous zinc-ion battery that directly uses bare zinc plate as the negative electrode, and significantly improves the electrochemical performance of only the polymer as the zinc negative electrode protective layer.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts an in-situ inorganic hybrid polymer film as a protective film for the zinc negative electrode, and introduces dopamine rich in catechol groups on the polymer using inorganic metal ions with good coordination ability. Catecholamine compounds (such as dopamine) contain catechol groups (catechol groups), have strong coordination ability, and can bind to metal ions. During the polymerization process, dopamine anchors metal ions on the polymer chain through coordination to form uniformly distributed metal-organic composite sites. These sites serve as nucleation centers for zinc ion deposition, guiding zinc ions to preferentially and uniformly deposit at specific locations rather than randomly stacking to form dendrites, thereby preventing dendrite formation; at the same time, metal ions form coordination bonds with the catechol groups of dopamine, thereby enhancing the mechanical strength and stability of the polymer film. Dopamine hydrochloride and iron ions improve the surface effect of the polymer during the polymerization process, reduce the overpotential of zinc ion deposition, and the uniform nucleation sites and low overpotential jointly weaken the tendency of "tip-first deposition", forcing zinc ions to deposit uniformly over a larger area, thereby alleviating the growth of zinc dendrites. Through the synergistic effect of the above substances, the electrode modified by in situ inorganic hybrid polymer membrane has a high current density (10mA / cm 2 、10mAh / cm 2 ) achieved an ultra-high cycle life of 1600 hours in the symmetrical battery cycling performance test, providing a new strategy for further improving energy storage and extending the cycle life of aqueous zinc-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a photo of a zinc negative electrode sample coated with an in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 of the present invention.

[0024] Figure 2 This is a scanning electron microscope image of the surface of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 of the present invention.

[0025] Figure 3 This is an electron micrograph of a cross-section of a zinc negative electrode coated with an in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 of the present invention.

[0026] Figure 4 The zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 of the present invention is subjected to a temperature of 25°C and 1 mA / cm 2 (1mAh / cm 2 ) conditions, and after 60 hours of cycling, this is the scanning electron microscope image of the zinc plate surface with the protective film removed.

[0027] Figure 5 The zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 was heated at 25°C and 1 mA / cm 2(1mAh / cm 2 ) conditions, and after 60 hours of cycling, the scanning electron microscope image of the zinc plate after ion beam sputtering with the protective film removed.

[0028] Figure 6 The zinc negative electrode coated with the polyether amide block copolymer (containing dopamine hydrochloride) protective film prepared in Comparative Example 1 of the present invention was tested at 25°C and 1 mA / cm 2 (1mAh / cm 2 ) conditions, and after 60 hours of cycling, this is the scanning electron microscope image of the zinc plate surface with the protective film removed.

[0029] Figure 7 This is a graph showing the cycle performance test results of a Zn-Zn symmetric battery assembled with zinc negative electrodes prepared in Examples 1-3 and Comparative Example 3 of the present invention.

[0030] Figure 8 This is a graph showing the charge and discharge cycle test results of a Zn-V2O5 full battery assembled with a zinc negative electrode coated with an in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1 of the present invention.

[0031] Fig. 9 This is a graph showing the cycle performance test results of a Zn-Zn symmetric battery assembled with zinc negative electrodes prepared in Example 4 of the present invention and Comparative Example 4. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Unless otherwise specified, the test methods used in the examples of the present invention are conventional methods; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified. The polymers used in some of the examples listed in the present invention are polyethers and polyether amide block copolymers, the polyether amide block copolymer is a commercial polyether amide block copolymer, and the polyether is selected from polyoxyethylene.

[0034] Example 1 The commercial polyetheramide block copolymer (PA6 / PEO) purchased from the market was dissolved in an ethanol / water (70 / 30wt%) mixture to form a 5wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.5wt% dopamine hydrochloride solution; the dopamine hydrochloride solution and the copolymer solution were uniformly mixed (the mass ratio of the copolymer to dopamine hydrochloride was 10:1), and stirred for 1h; a certain amount of ferric chloride was added to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride was 1:3), and stirred for 12h to obtain a casting solution; the casting solution was dripped at a rate of 85 μL cm -2 The ratio of the above-mentioned catalyst was evenly coated on a circular zinc plate with a diameter of 15 mm, and the plate was placed in a ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (10) coated with an in-situ inorganic hybrid polyether amide block copolymer protective film.

[0035] Digital photos of zinc anode coated with in-situ inorganic hybrid polyetheramide block copolymer protective film Figure 1 The surface scanning electron microscopy image of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film is shown in Figure 2 As shown, the cross-sectional scanning electron micrograph of the zinc negative electrode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film is shown in Figure 3 The protective film obtained in the embodiment of the present invention has a thickness of ≤10 μm.

[0036] Example 2

[0037] The commercial polyetheramide block copolymer (PA6 / PEO) purchased from the market was dissolved in an ethanol / water (70 / 30wt%) mixture to form a 5wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 1wt% dopamine hydrochloride solution, the dopamine hydrochloride solution and the copolymer solution were uniformly mixed (the mass ratio of the copolymer to dopamine hydrochloride was 10:1), and stirred for 1h; then a certain amount of ferric chloride was added to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride was 1:3), and stirred for 12h to obtain a casting solution; the casting solution was dripped at 85 μL cm -2 The ratio of 20 wt % was evenly coated on a circular zinc plate with a diameter of 15 mm, and the plate was placed in a ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (20) coated with an in-situ inorganic hybrid polyether amide block copolymer protective film (1 wt %).

[0038] Example 3

[0039] The commercial polyetheramide block copolymer (PA6 / PEO) purchased from the market was dissolved in ethanol / water (70 / 30wt%) to form a 5 wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.5 wt% dopamine hydrochloride solution, the dopamine hydrochloride solution and the copolymer solution were uniformly mixed (the mass ratio of the copolymer to dopamine hydrochloride was 10:1), and stirred for 1 hour; then a certain amount of aluminum chloride was added to the mixed solution (the molar ratio of aluminum chloride to dopamine hydrochloride was 1:3), and stirred for 12 hours to obtain a casting solution; the casting solution was dripped at 85 μL cm -2 The ratio of is evenly coated on a circular zinc plate with a diameter of 15 mm, and the plate is placed in a ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (30) coated with an in-situ inorganic hybrid polyether amide block copolymer protective film (aluminum ion).

[0040] Example 4

[0041] Polyethylene oxide was dissolved in anhydrous acetonitrile to form a 5 wt% polymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.5 wt% dopamine hydrochloride solution, the dopamine hydrochloride solution and the polymer solution were uniformly mixed (the mass ratio of polymer to dopamine hydrochloride was 10:1), and stirred for 1 hour; then a certain amount of aluminum chloride was added to the mixed solution (the molar ratio of aluminum chloride to dopamine hydrochloride was 1:3), and stirred for 12 hours to obtain a casting solution; the casting solution was dripped at 85 μL cm -2 The ratio of the inorganic hybrid polyether compound was evenly coated on a circular zinc plate with a diameter of 15 mm, and the plate was placed in a ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (70) coated with an in-situ inorganic hybrid polyether compound protective film.

[0042] Comparative Example 1 The commercial polyetheramide block copolymer (PA6 / PEO) was dissolved in ethanol / water (70 / 30 wt%) to form a 5 wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.5 wt% dopamine hydrochloride solution; the dopamine hydrochloride solution and the copolymer solution were uniformly mixed and stirred for 1 h to obtain a casting solution; the casting solution was dripped at 85 μLcm -2 The ratio of 200 μg / cm2 was uniformly coated on a circular zinc plate with a diameter of 15 mm, and the plate was placed in a ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (40) coated with a non-crosslinked polyetheramide mixed protective film (without metal ions). Comparative Example 1 Compared with Example 1, ferric chloride was not added.

[0043] Comparative Example 2 The commercial polyetheramide block copolymer (PA6 / PEO) purchased from the market was dissolved in an ethanol / water (70 / 30wt%) mixture to form a 5wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.5wt% dopamine hydrochloride solution, the dopamine hydrochloride solution and the copolymer solution were uniformly mixed and stirred for 1h; a certain amount of sodium chloride was added to the mixed solution (the molar ratio of sodium chloride to dopamine hydrochloride was 1:3), and stirred for 12h to obtain a casting solution; the casting solution was dripped at 85 μL cm -2 The ratio of is uniformly coated on a circular zinc plate with a diameter of 15 mm, and the plate is placed in a ventilated and dry place at room temperature for 12 hours using a solvent evaporation phase conversion method to obtain a zinc negative electrode (50) coated with a non-crosslinked polyetheramide mixed protective film (sodium ion). Comparative Example 2 Compared with Example 1, the added inorganic metal ion salt ferric chloride is replaced with sodium chloride.

[0044] Comparative Example 3 The commercial polyetheramide block copolymer (PA6 / PEO) purchased from the market was dissolved in an ethanol / water (70 / 30wt%) mixture to form a 5wt% copolymer solution; dopamine hydrochloride was dissolved in deionized water to form a 0.1wt% dopamine hydrochloride solution, which was uniformly mixed with the copolymer solution and stirred for 1h; a certain amount of ferric chloride was added to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride was 1:3), and stirred for 12h to obtain a casting solution; the casting solution was dripped at 85 μLcm -2 The ratio of 200 μg / ml was evenly coated on a circular zinc plate with a diameter of 15 mm, and the zinc negative electrode (60) coated with a oligodopamine polyetheramide hybrid protective film was obtained by using a solvent evaporation phase conversion method and placed in a ventilated and dry place at room temperature for 12 hours. Comparative Example 3 Compared with Example 1, the mass fraction of the dopamine hydrochloride solution was changed to 0.1wt%.

[0045] Comparative Example 4 Polyoxyethylene was dissolved in anhydrous acetonitrile to form a 5 wt% polymer solution. The solution was applied by drop coating at a rate of 85 μL cm -2 The ratio of the polyether compound was evenly coated on a circular zinc plate with a diameter of 15 mm, and the zinc negative electrode (80) was obtained by placing it in a ventilated and dry place at room temperature for 12 hours using the solvent evaporation phase conversion method.

[0046] Application Examples The zinc negative electrode coated with a protective film prepared in the embodiment and the comparative example is assembled into a Zn-Zn symmetric battery with a 2032 battery shell: the Zn-Zn symmetric battery assembly process is, in sequence, a negative electrode shell, a spring, a gasket, a zinc negative electrode coated with a protective film, a glass fiber separator, a zinc negative electrode coated with a protective film, and a positive electrode shell.

[0047] The zinc negative electrode (10) coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 was assembled into a Zn-Zn symmetric battery using a 2032 battery shell. 2 (1mAh / cm 2 ) conditions to test the performance of the protective film. After 60 hours of circulation, the surface scanning electron microscope image of the zinc negative electrode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film of Example 1 is as follows Figure 4 As shown in Figure 2, it can be found that the surface of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film is more uniform and dense, with a single morphology, and a large amount of dense and uniform single-crystalline zinc metal is distributed in the electrode deposition layer; the scanning electron microscope image after ion beam sputtering is shown in Figure 2. Figure 5 As shown in Figure 2, the zinc anode exhibits uniform and dense zinc ion deposition behavior, which is beneficial to the long cycle of the zinc anode. 2 (10mAh / cm 2 ) conditions, the cycle performance was tested, and the symmetrical battery remained stable after 1600 hours of cycling. Figure 7 shown.

[0048] The zinc negative electrode (20) coated with the in-situ inorganic hybrid polyether amide block copolymer protective film (1 wt%) prepared in Example 2 was assembled into a Zn-Zn symmetric battery using a 2032 battery shell. 2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 1550 hours of cycling. Figure 7 shown.

[0049] The zinc negative electrode (30) coated with the in-situ inorganic hybrid polyether amide block copolymer protective film (aluminum ion) prepared in Example 3 was assembled into a Zn-Zn symmetric battery using a 2032 battery shell. 2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 1400 hours of cycling. Figure 7 shown.

[0050] The zinc negative electrode (40) coated with a non-crosslinked polyether amide mixed protective film (without metal ions) prepared in Comparative Example 1 was assembled into a Zn-Zn symmetrical battery using a 2032 battery shell. The test conditions were: 25°C, 1 mA / cm 2 (1mAh / cm 2 ) condition, after 60 hours of cycling, the surface scanning electron microscope image of the zinc plate is as follows Figure 6 As shown in the figure, the zinc plate surface is unevenly deposited, and large zinc clusters appear, which is not conducive to the long cycle of the zinc negative electrode; at 25℃ and 10mA / cm2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 1230 hours of cycling. Figure 7 shown.

[0051] The zinc negative electrode (50) coated with the non-crosslinked polyetheramide mixed protective film (sodium ion) prepared in Comparative Example 2 was assembled into a Zn-Zn symmetrical battery using a 2032 battery shell. 2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 1200 hours of cycling. Figure 7 shown.

[0052] The zinc negative electrode (60) coated with the oligodopamine polyetheramide hybrid protective film prepared in Comparative Example 3 was assembled into a Zn-Zn symmetric battery using a 2032 battery shell. 2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 1330 hours of cycling. Figure 7 shown.

[0053] The Zn-V2O5 full battery assembly process is as follows: negative electrode shell, spring, gasket, zinc negative electrode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1, glass fiber separator, V2O5 (active material loading is 0.68 mg / cm 2 ), positive electrode shell; at 25°C, the cycle performance test was carried out with the current density set to 10A / g. The results are as follows Figure 8 As shown, the battery still maintained 168.5 mAh g after 7000 cycles. −1 The high capacity of the battery is 99.9% with a Coulombic efficiency (CE) of 90% and a capacity retention rate of 90%.

[0054] The zinc negative electrode (70) coated with the in-situ inorganic hybrid polyether compound protective film prepared in Example 4 was assembled into a Zn-Zn symmetric battery using a 2032 battery shell. 2 (10mAh / cm 2 ) conditions, the battery short-circuited after about 550 hours of cycling. Fig. 9 shown.

[0055] The zinc negative electrode (80) coated with a polyether compound protective film prepared in Comparative Example 4 was assembled into a Zn-Zn symmetrical battery using a 2032 battery shell. 2 (10mAh / cm 2) conditions, the battery short-circuited after about 290 hours of cycling. Fig. 9 shown.

[0056] In summary, the present invention provides a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer and a preparation method thereof, a zinc negative electrode coated with the protective film, and an aqueous zinc ion battery. Through the coupling effect between the oxyethylene group and the zinc ion in the polyetheramide block copolymer, dopamine rich in catechol groups is introduced into the polyetheramide block copolymer by using inorganic metal ions with good coordination ability to induce uniform deposition of zinc ions; at the same time, dopamine hydrochloride and ferric chloride will improve the surface effect of the polyetheramide block copolymer during the polymerization process, reduce the overpotential of zinc ion deposition, and significantly inhibit the formation and growth of dendrites. The modified electrode is used in an aqueous zinc ion battery, which greatly improves the capacity performance and cycle stability of the battery. This in-situ inorganic cross-linking mechanism is also applicable to other types of polymers such as polyethers, and the battery assembled with the in-situ inorganic hybridized polymer zinc negative electrode protective film has also been significantly improved in terms of cycle performance.

[0057] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymer, characterized in that: The following steps are involved: S1, dissolving the high molecular polymer to obtain a polymer solution; S2, uniformly mixing the catecholamine compound solution with the polymer solution in step S1 to obtain a mixed solution; S3, adding an inorganic metal ion salt having coordination ability to the mixed solution described in step S2 and stirring evenly to obtain a film casting solution; S4, uniformly coating the casting solution in step S3 on the zinc surface, and obtaining the zinc negative electrode protective film after drying; The polymer in step S1 is a polyether or polyether amide block copolymer.

2. The preparation method according to claim 1, characterized in that: The polyetheramide block copolymer is selected from any one of polyamide 6-polyethylene oxide block copolymer, polyamide 11-polyethylene oxide block copolymer and polyamide 12-polyethylene oxide block copolymer.

3. The preparation method according to claim 1, characterized in that: The concentration of the polymer solution in step S1 is 5-10wt%.

4. The preparation method according to claim 1, characterized in that: The catecholamine compound in step S2 is dopamine hydrochloride, and the concentration of the solution is 0.5-1 wt%.

5. The preparation method according to claim 1, characterized in that: The inorganic metal ion salt described in step S3 is selected from any one of iron ion salt, manganese ion salt, chromium ion salt and aluminum ion salt.

6. The preparation method according to claim 5, characterized in that: The iron ion salt is one of ferric chloride, ferric nitrate and ferric sulfate.

7. The preparation method according to claim 1, characterized in that: In step S3, the molar ratio of the inorganic metal ion salt to the catecholamine compound in the casting solution is 1:2-1:5, and the mass ratio of the polymer to the catecholamine compound is 10:1-15:

1.

8. Use of the zinc negative electrode protective film constructed by the in-situ inorganic hybrid polymer prepared by the method according to any one of claims 1 to 7 in improving the capacity performance and cycle stability of aqueous zinc ion batteries.

9. An aqueous zinc ion battery, characterized in that: The invention comprises a zinc negative electrode protective film constructed by an in-situ inorganic hybrid polymer prepared by the method described in any one of claims 1 to 7.

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