A zinc anode protective film constructed by in-situ inorganic hybrid polymer, its preparation method and application

Abstract

The present invention relates to the technical field of zinc ion batteries, and specifically discloses a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymer, and a preparation method and application thereof. The preparation method includes: dissolving a high molecular polymer to form a solution, adding a catecholamine compound and an inorganic metal salt solution to the solution to obtain a casting solution, uniformly coating the casting solution on a zinc plate, and removing the solvent. The present invention introduces dopamine rich in catechol groups on the polymer by inorganic metal ions, which can induce uniform deposition of zinc ions; meanwhile, dopamine hydrochloride and inorganic metal ions improve the surface effect of the polymer during the polymerization process, reduce the overpotential of zinc ion deposition, and further inhibit the formation and growth of zinc dendrites. The modified electrode has ultra-long cycle stability and good capacity retention rate when used in aqueous zinc ion batteries, providing a new strategy for further improving energy storage and extending the life of zinc ion batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc-ion batteries, and particularly relates to a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymers, a preparation method thereof, and an 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 fields of energy storage and mobile energy. However, in practical applications, directly using zinc metal negative electrodes has many problems that seriously hinder its large-scale application: during the charge and discharge process, the electrodeposition of zinc ions tends to be dendritic and uneven, and dendrites are easily generated to pierce the separator, resulting in internal short circuits of the battery, seriously affecting the cycle performance and safety of the battery; in addition, hydrogen evolution reactions are likely to occur on the surface of the zinc negative electrode and by-products are generated, which will also reduce the capacity and life of the battery. Therefore, how to protect the zinc negative electrode has become one of the important ways to improve the stability and cycle life of zinc-ion batteries.

[0003] Currently, common zinc negative electrode protection methods include coating protective films, adding chemical additives, etc. Chinese Patent CN118969946 A discloses a preparation method and application of a zinc negative electrode protective layer with a hydrophilic-hydrophobic alternating structure, including dissolving a hydrophilic-hydrophobic block copolymer in ethanol / water to prepare a casting solution, and using a coating method to uniformly deposit the hydrophilic-hydrophobic block copolymer on the zinc surface; using a block copolymer with a hydrophilic-hydrophobic alternating structure as the protective layer of the zinc negative electrode significantly improves the cycle stability of the battery compared with directly using a bare zinc plate as the negative electrode of an aqueous zinc-ion battery. Although these methods have solved the above zinc negative electrode problems to a certain extent, after the zinc negative electrode coated with this copolymer is subjected to a cycle test, the zinc crystals in the zinc negative electrode deposition layer do not show deposition on specific crystal planes, which affects the electrochemical performance of the protective layer to a certain extent and is not conducive to the further industrialization process of aqueous zinc-ion batteries; moreover, the capacity performance and cycle life of the aqueous zinc ions need to be further improved. Therefore, more effective measures must be taken to inhibit the formation and growth of dendrites and slow down the occurrence of side reactions, and further improve the capacity performance and cycle stability of zinc-ion batteries, which is an urgent technical problem to be solved in the field. Summary of the Invention

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

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a method for preparing a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymer, comprising the following steps:

[0007] S1. Dissolve the high molecular polymer to obtain a polymer solution;

[0008] S2. Uniformly mix the catecholamine compound solution with the polymer solution described in step S1;

[0009] S3. Add an inorganic metal ion salt with coordination ability to the mixed solution described in step S2 and stir evenly to obtain a casting solution;

[0010] S4. Uniformly coat the casting solution described in step S3 on the surface of zinc metal, and obtain the zinc negative electrode protective film after drying.

[0011] Preferably, the high molecular polymer described in step S1 includes but is not limited to polymers such as polyethers, polyesters, polyamides, polyurethanes, polyetheramide block copolymers, and chitosan.

[0012] More preferably, the polyetheramide block copolymer can be selected from commercial products, and any one of polyetheramide block copolymers such as polyamide 6-polyoxyethylene block copolymer, polyamide 11-polyoxyethylene block copolymer, and polyamide 12-polyoxyethylene block copolymer.

[0013] More preferably, the polyether is polyoxyethylene.

[0014] Preferably, the concentration of the polymer solution described in step S1 is 5-10 wt%.

[0015] Preferably, the catecholamine compound described in step S2 is dopamine hydrochloride.

[0016] More preferably, the concentration of the dopamine hydrochloride solution is 0.5-1 wt%.

[0017] The inorganic metal ions with coordination ability in the present invention refer to those inorganic metal ions having good coordination ability. The present invention utilizes the inorganic metal ions with good coordination ability to crosslink with the polymer, introducing dopamine rich in catechol groups onto the polymer. The catechol groups have a stronger binding ability with zinc ions. Dopamine anchors metal ions on the polymer chain through coordination, forming uniformly distributed metal-organic composite sites. These sites serve as nucleation centers for zinc ion deposition, which can induce more uniform zinc ion deposition 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 membrane. Meanwhile, the in-situ generated inorganic nano-hybrid membrane from the polymerization of dopamine hydrochloride and inorganic metal ions can change the surface state of the polymer, effectively reducing the zinc deposition overpotential caused by the coverage of the protective film, and can effectively inhibit the growth of zinc dendrites.

[0018] Preferably, the metal ion salt with coordination ability in step S3 is one of iron ions, manganese ions, chromium ions, aluminum ion salts, etc.; more preferably, it is a transition metal ion salt.

[0019] Further preferably, the iron ion salt can be selected from one of ferric chloride, ferric nitrate, ferric sulfate, etc.

[0020] Preferably, in the casting solution of step S3, the molar ratio of the inorganic metal ion salt to the catecholamine compound is 1:2 to 1:5, and the mass ratio of the polymer to the catecholamine compound is 10:1 to 15:1.

[0021] Preferably, the coating method in step S4 adopts any one of drop coating, blade coating, spin coating and spraying methods. After coating, it is dried at room temperature, the temperature is 15~30 °C, and the drying time is 8~24 h.

[0022] Preferably, the film thickness of the zinc negative electrode protective film in step S4 is ≤10 μm.

[0023] In the 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.

[0024] In the third aspect, the present invention provides the application of the zinc negative electrode protective film constructed by the above in-situ inorganic hybrid polymer in improving the capacity performance and cycle stability performance of an aqueous zinc ion battery.

[0025] In the fourth aspect, the present invention provides a zinc ion battery negative electrode plate, including the zinc negative electrode protective film constructed by the above in-situ inorganic hybrid polymer.

[0026] Fifth aspect, the present invention provides an aqueous zinc-ion battery, including 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. The modified electrode at 25°C, high current density (10 mA / cm 2 、10 mAh / cm 2 ), the symmetric battery cycling performance far exceeds the cycling life of directly using a bare zinc plate as the negative electrode of the aqueous zinc-ion battery at present, and significantly improves the electrochemical performance of only the polymer as the protective layer of the zinc negative electrode.

[0027] Compared with the prior art, the beneficial effects of the present application are as follows:

[0028] The present invention uses 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 by using inorganic metal ions with good coordination ability. Catecholamine compounds (such as dopamine) contain catechol groups (catechol groups) and have strong coordination ability, which can combine with 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 deposit uniformly at specific positions rather than randomly piling up to form dendrites, preventing 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. Dopamine hydrochloride and iron ions will improve the surface effect of the polymer during the polymerization process, reduce the overpotential of zinc ion deposition. The uniform nucleation sites and low overpotential together weaken the tendency of "tip-first deposition", forcing zinc ions to deposit uniformly over a larger area, alleviating the growth of zinc dendrites. Through the synergistic effect between the above substances, the electrode modified with the in-situ inorganic hybrid polymer film has an ultra-high cycling life of 1600 hours in the symmetric battery cycling performance test at 25°C, high current density (10 mA / cm 2 、10 mAh / cm 2 ), providing a new strategy for further improving energy storage and extending the cycling life of aqueous zinc-ion batteries. Description of the Drawings

[0029] Figure 1 It is a photo of the zinc negative electrode sample coated with an in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 of the present invention.

[0030] Figure 2 It is a scanning electron microscope image of the surface of the zinc negative electrode coated with an in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 of the present invention.

[0031] Figure 3Cross-sectional electron micrograph of the zinc anode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 of the present invention.

[0032] Figure 4 The zinc anode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 of the present invention was tested at 25 °C and 1 mA / cm 2 (1 mAh / cm 2 ). After 60 hours of cycling, the scanning electron micrograph of the surface of the zinc plate after removing the protective film.

[0033] Figure 5 The zinc anode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 was tested at 25 °C and 1 mA / cm 2 (1 mAh / cm 2 ). After 60 hours of cycling, the scanning electron micrograph of the zinc plate after ion beam sputtering after removing the protective film.

[0034] Figure 6 The zinc anode 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 (1 mAh / cm 2 ). After 60 hours of cycling, the scanning electron micrograph of the surface of the zinc plate after removing the protective film.

[0035] Figure 7 Graph showing the test results of the cycling performance of the Zn-Zn symmetric battery assembled with the zinc anodes prepared in Examples 1-3 and Comparative Examples -3 of the present invention.

[0036] Figure 8 Graph showing the charge-discharge cycling test results of the Zn-V2O5 full battery assembled with the zinc anode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film prepared in Example 1 of the present invention.

[0037] Figure 9 Graph showing the test results of the cycling performance of the Zn-Zn symmetric battery assembled with the zinc anodes prepared in Example 4 and Comparative Example 4 of the present invention. Detailed implementation manners

[0038] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Unless otherwise specified, the test methods used in the embodiments of the present invention are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, are reagents and materials that can be obtained commercially. The polymers used in some of the embodiments listed in the present invention are polyethers and polyetheramide block copolymers. The polyetheramide block copolymer is a commercial polyetheramide block copolymer, and the polyether selected is polyethylene oxide.

[0040] Example 1

[0041] By dissolving a commercially available polyetheramide block copolymer (PA6 / PEO) in an ethanol / water (70 / 30 wt%) mixture to form a 5 wt% copolymer solution; dissolving dopamine hydrochloride in deionized water to form a 0.5 wt% dopamine hydrochloride solution; uniformly mixing the dopamine hydrochloride solution with the copolymer solution (the mass ratio of the copolymer to dopamine hydrochloride is 10:1), and stirring for 1 h; then adding a certain amount of ferric chloride to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride is 1:3), and stirring for 12 h to obtain a casting solution; using the casting solution by the drop-coating method, uniformly coating it on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2 to obtain a zinc negative electrode (10) coated with an in-situ inorganic hybrid polyetheramide block copolymer protective film by solvent evaporation phase inversion method and placing it at room temperature in a ventilated and dry place for 12 h.

[0042] The digital photo of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film is as Figure 1 shown, the surface scanning electron micrograph of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film is as Figure 2 shown, and the cross-sectional scanning electron micrograph of the zinc negative electrode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film is as Figure 3 shown. The protective film obtained in the embodiment of the present invention has a thickness of ≤10 μm.

[0043] Example 2

[0044] By dissolving a commercially available polyetheramide block copolymer (PA6 / PEO) in an ethanol / water (70 / 30 wt%) mixture to form a 5 wt% copolymer solution; dissolving dopamine hydrochloride in deionized water to form a 1 wt% dopamine hydrochloride solution, uniformly mixing the dopamine hydrochloride solution with the copolymer solution (the mass ratio of the copolymer to dopamine hydrochloride is 10:1), and stirring for 1 h; then adding a certain amount of ferric chloride to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride is 1: / 3), and stirring for 12 h to obtain a casting solution; using the casting solution by the drop-coating method, uniformly coating it on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2Coat it evenly on a circular zinc plate with a diameter of 15 mm at a certain ratio, and use the solvent evaporation phase inversion method. Place it at room temperature in a ventilated and dry place 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%).

[0045] Example 3

[0046] Dissolve the commercially available polyether amide block copolymer (PA6 / PEO) in ethanol / water (70 / 30 wt%) to form a 5 wt% copolymer solution; dissolve dopamine hydrochloride in deionized water to form a 0.5 wt% dopamine hydrochloride solution, and uniformly mix the dopamine hydrochloride solution with the copolymer solution (the mass ratio of the copolymer to dopamine hydrochloride is 10:1), and stir for 1 h; then add a certain amount of aluminum chloride to the mixed solution (the molar ratio of aluminum chloride to dopamine hydrochloride is 1:3), and stir for 12 h to obtain a casting solution; use the drop coating method to coat the casting solution evenly on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2 Coat it evenly on a circular zinc plate with a diameter of 15 mm at a certain ratio, and use the solvent evaporation phase inversion method. Place it at room temperature in a ventilated and dry place for 12 h to obtain a zinc negative electrode (30) coated with an in-situ inorganic hybrid polyether amide block copolymer protective film (aluminum ions).

[0047] Example 4

[0048] Dissolve polyethylene oxide in anhydrous acetonitrile to form a 5 wt% polymer solution; dissolve dopamine hydrochloride in deionized water to form a 0.5 wt% dopamine hydrochloride solution, and uniformly mix the dopamine hydrochloride solution with the polymer solution (the mass ratio of the polymer to dopamine hydrochloride is 10:1), and stir for 1 h; then add a certain amount of aluminum chloride to the mixed solution (the molar ratio of aluminum chloride to dopamine hydrochloride is 1:3), and stir for 12 h to obtain a casting solution; use the drop coating method to coat the casting solution evenly on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2 Coat it evenly on a circular zinc plate with a diameter of 15 mm at a certain ratio, and use the solvent evaporation phase inversion method. Place it at room temperature in a ventilated and dry place for 12 h to obtain a zinc negative electrode (70) coated with an in-situ inorganic hybrid polyether compound protective film.

[0049] Comparative Example 1

[0050] Dissolve the commercially available polyether amide block copolymer (PA6 / PEO) in ethanol / water (70 / 30 wt%) to form a 5 wt% copolymer solution; dissolve dopamine hydrochloride in deionized water to form a 0.5 wt% dopamine hydrochloride solution; uniformly mix the dopamine hydrochloride solution with the copolymer solution and stir for 1 h to obtain a casting solution; use the drop coating method to coat the casting solution at a ratio of 85 μLcm -2Coat a zinc plate with a diameter of 15 mm uniformly with a certain proportion, and use the solvent evaporation phase inversion method. Place it in a well-ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (40) coated with a non-crosslinked polyether amide mixed protective film (without metal ions). Compared with Example 1, in Comparative Example 1, ferric chloride is not added.

[0051] Comparative Example 2

[0052] Dissolve a commercially available polyether amide block copolymer (PA6 / PEO) in an ethanol / water (70 / 30 wt%) mixed solution to form a 5 wt% copolymer solution; dissolve dopamine hydrochloride in deionized water to form a 0.5 wt% dopamine hydrochloride solution, and uniformly mix the dopamine hydrochloride solution with the copolymer solution and stir for 1 h; then add a certain amount of sodium chloride to the mixed solution (the molar ratio of sodium chloride to dopamine hydrochloride is 1:3), and stir for 12 h to obtain a casting solution; use the drop coating method to uniformly coat the casting solution on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2 Coat a zinc plate with a diameter of 15 mm uniformly with a certain proportion, and use the solvent evaporation phase inversion method. Place it in a well-ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (50) coated with a non-crosslinked polyether amide mixed protective film (sodium ions). Compared with Example 1, in Comparative Example 2, the added inorganic metal ion salt ferric chloride is changed to sodium chloride.

[0053] Comparative Example 3

[0054] Dissolve a commercially available polyether amide block copolymer (PA6 / PEO) in an ethanol / water (70 / 30 wt%) mixed solution to form a 5 wt% copolymer solution; dissolve dopamine hydrochloride in deionized water to form a 0.1 wt% dopamine hydrochloride solution, uniformly mix it with the copolymer solution, and stir for 1 h; then add a certain amount of ferric chloride to the mixed solution (the molar ratio of ferric chloride to dopamine hydrochloride is 1:3), and stir for 12 h to obtain a casting solution; use the drop coating method to uniformly coat the casting solution on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μLcm -2 Coat a zinc plate with a diameter of 15 mm uniformly with a certain proportion, and use the solvent evaporation phase inversion method. Place it in a well-ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (60) coated with a polydopamine polyether amide hybrid protective film. Compared with Example 1, in Comparative Example 3, the mass fraction of the dopamine hydrochloride solution is changed to 0.1 wt%.

[0055] Comparative Example 4

[0056] Dissolve polyoxyethylene in anhydrous acetonitrile to form a 5 wt% polymer solution; use the drop coating method to uniformly coat the solution on a circular zinc plate with a diameter of 15 mm at a ratio of 85 μL cm -2 Coat a zinc plate with a diameter of 15 mm uniformly with a certain proportion, and use the solvent evaporation phase inversion method. Place it in a well-ventilated and dry place at room temperature for 12 h to obtain a zinc negative electrode (80) coated with a polyether compound protective film.

[0057] Application Example

[0058] The zinc negative electrodes coated with the protective film prepared in the examples and comparative examples were assembled into Zn-Zn symmetric cells using a 2032 battery case: the assembly process of the Zn-Zn symmetric cell was, in sequence, the negative electrode case, the shrapnel, the gasket, the zinc negative electrode coated with the protective film, the glass fiber separator, the zinc negative electrode coated with the protective film, and the positive electrode case.

[0059] 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 cell using a 2032 battery case. At 25 °C, 1 mA / cm 2 (1 mAh / cm 2 ) conditions, the performance of the protective film was tested. After 60 hours of cycling, the scanning electron microscopy image of the surface of the zinc negative electrode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film in Example 1 was as shown in Figure 4 It can be found that the surface of the zinc negative electrode coated with the in-situ inorganic hybrid polyether amide block copolymer protective film is more uniform and dense, with a single morphology, and a large number of dense and uniform single-crystalline zinc metals are distributed in the electrode deposition layer; the scanning electron microscopy image after ion beam sputtering is as shown in Figure 5 It shows that the zinc negative electrode exhibits uniform and dense zinc ion deposition behavior, which is beneficial to the long cycling of the zinc negative electrode. At 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ) conditions, its cycling performance was tested. After cycling for 1600 hours, its symmetric cell still remained stable, and the results were as shown in Figure 7 .

[0060] 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 cell using a 2032 battery case. At 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ) conditions, its cycling performance was tested. After cycling for about 1550 hours, the battery short-circuited, and the results were as shown in Figure 7 .

[0061] The zinc negative electrode (30) coated with the in-situ inorganic hybrid polyether amide block copolymer protective film (aluminum ions) prepared in Example 3 was assembled into a Zn-Zn symmetric cell using a 2032 battery case. At 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ) conditions, its cycling performance was tested. After cycling for about 1400 hours, the battery short-circuited, and the results were as shown in Figure 7 .

[0062] The zinc anode (40) coated with the non-crosslinked polyetheramide mixed protective film (without metal ions) prepared in Comparative Example 1 was assembled into a Zn-Zn symmetric battery using a 2032 battery case. The test conditions were: 25 °C, 1 mA / cm 2 (1 mAh / cm 2 ). After 60 hours of cycling, the scanning electron microscope image of the zinc plate surface is as shown in Figure 6 . The deposition on the zinc plate surface was uneven, and large zinc clusters appeared, which was not conducive to the long-term cycling of the zinc anode; at 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ), its cycling performance was tested. After cycling for about 1230 hours, the battery short-circuited, and the results are as shown in Figure 7 .

[0063] The zinc anode (50) coated with the non-crosslinked polyetheramide mixed protective film (sodium ions) prepared in Comparative Example 2 was assembled into a Zn-Zn symmetric battery using a 2032 battery case. At 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ), its cycling performance was tested. After cycling for about 1200 hours, the battery short-circuited, and the results are as shown in Figure 7 .

[0064] The zinc anode (60) coated with the low molecular weight dopamine polyetheramide hybrid protective film prepared in Comparative Example 3 was assembled into a Zn-Zn symmetric battery using a 2032 battery case. At 25 °C, 10 mA / cm 2 (10 mAh / cm 2 ), its cycling performance was tested. After cycling for about 1330 hours, the battery short-circuited, and the results are as shown in Figure 7 .

[0065] For the assembly process of the Zn-V2O5 full battery, it was in sequence: the negative electrode case, the shrapnel, the gasket, the zinc anode coated with the in-situ inorganic hybrid polyetheramide block copolymer protective film prepared in Example 1, the glass fiber separator, V2O5 (the active material loading was 0.68 mg / cm 2 ), and the positive electrode case; at 25 °C, the cycling performance was tested, and the current density was set to 10 A / g. The results are as shown in Figure 8 . The battery still maintained a high capacity of 168.5 mAh g −1 after 7000 cycles, the Coulomb efficiency (CE) was 99.9%, and the capacity retention rate was as high as 90%.

[0066] The zinc anode (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 case. At 25 °C, 10 mA / cm 2 (10 mAh / cm2 ), its cycling performance was tested under the condition of (10 mA / cm² (10 mAh / cm²)). After cycling for about 550 hours, the battery short-circuited, and the results are as Figure 9 shown.

[0067] The zinc negative electrode (80) coated with a polyether compound protective film prepared in Comparative Example 4 was assembled into a Zn-Zn symmetric battery using a 2032 battery case. Its cycling performance was tested under the conditions of 25 °C and 10 mA / cm² (10 mAh / cm²). After cycling for about 290 hours, the battery short-circuited, and the results are as 2 (10 mAh / cm² 2 ). After cycling for about 290 hours, the battery short-circuited, and the results are as Figure 9 shown.

[0068] In summary, the present invention provides a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymers, its preparation method, a zinc negative electrode coated with this protective film, and an aqueous zinc ion battery. Through the coupling effect of the oxyethylene groups in the polyether amide block copolymer with zinc ions, inorganic metal ions with good coordination ability are used to introduce dopamine rich in catechol groups onto the polyether amide block copolymer, inducing uniform deposition of zinc ions. At the same time, dopamine hydrochloride and ferric chloride will improve the surface effect of the polyether amide block copolymer during the polymerization process, reduce the overpotential of zinc ion deposition, and significantly inhibit the formation and growth of dendrites. When the modified electrode is used in an aqueous zinc ion battery, the capacity performance and cycling stability of the battery are greatly improved. This in-situ inorganic crosslinking mechanism is also applicable to other types of polymers such as polyethers. The batteries assembled with the zinc negative electrode protective film of the in-situ inorganic hybrid polymer have also been significantly improved in terms of cycling performance.

[0069] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, rather than limitations on the specific implementation manners of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a zinc negative electrode protective film constructed by in-situ inorganic hybrid polymers, characterized in that, It includes the following steps: S1. Dissolve the high molecular polymer to obtain a polymer solution; S2. Uniformly mix the catecholamine compound solution with the polymer solution described in step S1 to obtain a mixed solution; S3. Add the inorganic metal ion salt with coordination ability to the mixed solution described in step S2 and stir evenly to obtain a casting solution; S4. Uniformly coat the casting solution described in step S3 on the zinc surface, and obtain the zinc negative electrode protective film after drying; The polymer described in step S1 is a polyether or a polyether amide block copolymer; The inorganic metal ion salt described in step S3 is selected from any one of ferric ion salts, manganese ion salts, chromium ion salts, and aluminum ion salts.

2. The preparation method according to claim 1, characterized in that, The polyether amide block copolymer is selected from any one of polyamide 6-polyoxyethylene block copolymer, polyamide 11-polyoxyethylene block copolymer, and polyamide 12-polyoxyethylene block copolymer.

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

4. The preparation method according to claim 1, characterized in that, The catecholamine compound described 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 ferric ion salt is one of ferric chloride, ferric nitrate, and ferric sulfate.

6. The preparation method according to claim 1, characterized in that, In the casting solution described in 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.

7. Application of the zinc negative electrode protective film constructed by the in-situ inorganic hybrid polymer prepared by the method described in any one of claims 1-6 in improving the capacity performance and cycle stability of the aqueous zinc ion battery.

8. An aqueous zinc-ion battery, characterized in that, It includes the zinc negative electrode protective film constructed by the in-situ inorganic hybrid polymer prepared by the method described in any one of claims 1-6.

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