Positive electrode sheet, method for manufacturing the same, and battery

Abstract

The application discloses a positive pole piece, a preparation method thereof and a battery. The preparation method of the positive pole piece comprises the following steps: performing sputtering on a metal vanadium target by using a magnetron sputtering method and / or a pulsed laser sputtering method, so as to deposit a vanadium oxide film on a conductive substrate, and obtaining the positive pole piece. The method is simple in preparation process, is suitable for large-scale industrial production, and can be used to prepare the positive pole piece with good electrochemical stability and high specific capacity, and is suitable for a wide range of applications.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of batteries, and in particular, relates to a positive electrode sheet and a preparation method thereof, and a battery. BACKGROUND

[0002] At present, the energy storage battery industry is developing rapidly, and the poor safety and high cost of traditional lithium ion batteries hinder their commercial application. Therefore, it is particularly important to prepare energy storage batteries with high electrochemical performance, environmental friendliness and low cost. Among them, aqueous zinc ion batteries have become one of the most promising candidates to replace lithium ion batteries due to their low manufacturing cost, high energy density, good stability, high safety, and abundant zinc reserves.

[0003] The positive active material of the aqueous zinc ion battery is an important factor affecting the overall electrochemical performance. So far, the existing positive materials of the aqueous zinc ion battery are mostly selected from Prussian blue analogues, manganese-based oxides and vanadium-based oxides, etc. Vanadium-based materials have a layered structure that is beneficial to the deintercalation of zinc ions, and have a large application prospect due to their low cost. SUMMARY

[0004] The present application is mainly based on the following problems and discoveries:

[0005] At present, the vanadium-based positive materials for preparing aqueous zinc ion batteries are mostly prepared by hydrothermal synthesis method. For example, it is proposed to mix vanadate aqueous solution and aniline and adjust the pH value of the mixed solution to 0.7-1.1, and then react at 180-200℃ for 24-48h, and then perform solid-liquid separation to obtain vanadium dioxide solid phase. For another example, it is proposed to mix vanadium pentoxide with a water-soluble salt of a metal, adjust the pH value to 1-4, the reaction temperature to 90-200℃, and the reaction time to 12-72h, and then perform hydrothermal synthesis reaction, and then perform centrifugation or filtration, washing and drying processes after the reaction to obtain the positive material of the aqueous zinc ion battery. The above method has a long reaction time and a complex process, which is difficult to meet the needs of energy saving and emission reduction in industrial production, and the regulation mode of the phase composition of the vanadium-based positive material is complex, which is not conducive to the comprehensive analysis of the influence of vanadium oxide with different compositions on the battery performance.

[0006] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to propose a positive electrode sheet and a preparation method thereof, and a battery. The method not only has a simple preparation process and is suitable for large-scale industrial production, but also can prepare a positive electrode sheet with good electrochemical stability and high specific capacity, and has a wide range of applications.

[0007] In one aspect of the present application, the present application provides a method for preparing a positive electrode sheet. According to an embodiment of the present application, the method comprises: sputtering a metal vanadium target by a magnetron sputtering method and / or a pulsed laser sputtering method to deposit a vanadium oxide film on a conductive substrate, thereby obtaining a positive electrode sheet.

[0008] The method for preparing a positive electrode sheet according to the above-mentioned embodiments of the present application has at least the following beneficial effects: 1) the method can be used to prepare a positive electrode sheet with a layered or tunnel-like structure, which has a larger specific capacity and a higher electrode potential, and is suitable for ion deintercalation (especially zinc ion deintercalation), thereby being beneficial to improving the specific capacity and stability of an ion battery (especially a zinc ion battery); 2) the vanadium oxide is deposited by a magnetron sputtering method and / or a pulsed laser sputtering method, which can effectively realize large-area film deposition, and the method has a simple process, a low raw material cost and high safety, thereby being beneficial to realizing large-scale industrial production; 3) compared with a vanadium oxide bulk, the vanadium oxide product prepared by the method has a more controllable structure and high production stability; on the other hand, it is easier to quantitatively characterize the product, thereby being beneficial to improving the accuracy and stability of test results; on the other hand, the product has a wider application, and can be assembled to obtain a flexible zinc ion battery, thereby realizing more folding or curling functional applications; 4) the method can be used to conveniently adjust the phase composition of the vanadium oxide film, which is not only beneficial to more comprehensively analyzing the electrochemical performance of vanadium oxide films with different compositions as positive electrode materials of aqueous zinc ion batteries, but also can adjust the composition of the vanadium oxide film according to different requirements, thereby being beneficial to increasing the application range and use flexibility of the positive electrode sheet.

[0009] In addition, the method for preparing a positive electrode sheet according to the above-mentioned embodiments of the present application can have the following additional technical features:

[0010] In some embodiments of the present application, the method comprises: introducing a sputtering gas and oxygen into a vacuum chamber of a sputtering device under a background vacuum degree, and adjusting the phase composition of the vanadium oxide film formed on the conductive substrate by controlling the oxygen partial pressure and / or the reaction temperature in the reaction process.

[0011] In some embodiments of the present application, the background vacuum degree is not more than 4x10 -3 Pa, and optionally not more than 7x10 - 4 Pa.

[0012] In some embodiments of the present application, the sputtering gas is argon.

[0013] In some embodiments of the present application, the reaction temperature is 25-500℃, and optionally 100-500℃.

[0014] In some embodiments of the present application, the purity of the sputtering gas is not less than 99.99%, and the purity of the oxygen is not less than 99.99%.

[0015] In some embodiments of the present application, the sputtering gas and the oxygen are introduced into the vacuum chamber, and the total gas pressure in the vacuum chamber is controlled to be 0.1-2 Pa, and the oxygen partial pressure is controlled to be 1-10%, or the oxygen partial pressure is controlled to be 2-5%.

[0016] In some embodiments of the present application, the conductive substrate comprises a metal sheet and / or conductive glass.

[0017] In some embodiments of the present application, the thickness of the conductive substrate is not greater than 5 mm.

[0018] In some embodiments of the present application, the purity of the metal vanadium target is not less than 99.99%.

[0019] In some embodiments of the present application, the vanadium oxide film comprises at least one of V6O 13 , V2O5, V4O7 and VO2. In some embodiments of the present application, the thickness of the vanadium oxide film is not less than 100 nm, or not less than 200 nm.

[0020] In some embodiments of the present application, the metal sheet comprises a 304 stainless steel sheet and / or a metal molybdenum sheet, and the conductive glass comprises transparent conductive glass.

[0021] In some embodiments of the present application, the vanadium oxide film is deposited on at least one surface of the conductive substrate.

[0022] In some embodiments of the present application, at least one of the following conditions is met when the vanadium oxide film is deposited on the conductive substrate by the magnetron sputtering method: the power density is 1-3 W / cm 2 , the distance between the metal vanadium target and the conductive substrate is 40-150 mm, and the sputtering time is 0.5-10 h.

[0023] In some embodiments of the present application, at least one of the following conditions is met when the vanadium oxide film is deposited on the conductive substrate by the pulsed laser sputtering method: the energy density is 1-2 J / cm 2 , the frequency is 3-8 Hz, and the distance between the metal vanadium target and the conductive substrate is 40-70 mm.

[0024] In some embodiments of the present application, before the vanadium oxide film is deposited on the conductive substrate, the target is subjected to a pre-sputtering treatment.

[0025] In some embodiments of the present application, the pre-sputtering treatment of the target material is performed for 10-30 minutes.

[0026] In some embodiments of the present application, the reaction temperature is controlled to be 450-500 DEG C, and the oxygen partial pressure is controlled to be 3-4%, so as to obtain a vanadium oxide film comprising at least one of V2O5, V6O 13 , and / or V2O5.

[0027] In some embodiments of the present application, the reaction temperature is controlled to be 300-400 DEG C, and the oxygen partial pressure is controlled to be 3-4%, so as to obtain a vanadium oxide film comprising at least one of V2O5, V6O 13 , and / or V2O5.

[0028] In some embodiments of the present application, the reaction temperature is controlled to be 300-400 DEG C, and the oxygen partial pressure is controlled to be 2-2.5%, so as to obtain a vanadium oxide film comprising at least one of V4O7 and / or V2O5.

[0029] In some embodiments of the present application, the reaction temperature is controlled to be 180-250 DEG C, and the oxygen partial pressure is controlled to be 3-4%, so as to obtain a vanadium oxide film comprising VO2.

[0030] In still another aspect of the present application, the present application provides a positive electrode plate prepared by the above method. The features and effects described for the above method for preparing a positive electrode plate are also applicable to the positive electrode plate, which will not be repeated here. In general, the positive electrode plate not only has good electrochemical stability and high specific capacity, but also has simple preparation process and wide application range.

[0031] In still another aspect of the present application, the present application provides a battery comprising the above positive electrode plate and / or the positive electrode plate prepared by the above method according to embodiments of the present application. The features and effects described for the above positive electrode plate and the above method for preparing a positive electrode plate are also applicable to the battery, which will not be repeated here. In general, compared with the prior art, the battery not only has low manufacturing cost, but also can balance high specific capacity and good electrochemical stability.

[0032] In some embodiments of the present application, the battery is a water-based zinc ion battery or an aluminum ion battery.

[0033] In some embodiments of the present application, the battery is a button cell, a stacked cell, or a wound cell.

[0034] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0035] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the references to the following drawings:

[0036] Figure 1 are SEM images of vanadium oxide films obtained according to the present application in Examples 1 to 4, wherein Figure 1 (a) is an SEM image of a vanadium oxide film obtained in Example 1, Figure 1 (b) is an SEM image of a vanadium oxide film obtained in Example 2, Figure 1 (c) is an SEM image of a vanadium oxide film obtained in Example 3, Figure 1 (d) is an SEM image of a vanadium oxide film obtained in Example 4;

[0037] Figure 2 are SEM images of vanadium oxide films obtained according to the present application in Examples 2, 5 to 7, wherein Figure 2 (a) is an SEM image of a vanadium oxide film obtained in Example 5, Figure 2 (b) is an SEM image of a vanadium oxide film obtained in Example 6, Figure 2 (c) is an SEM image of a vanadium oxide film obtained in Example 2, Figure 2 (d) is an SEM image of a vanadium oxide film obtained in Example 7;

[0038] Figure 3 are XRD patterns of vanadium oxide films obtained according to the present application in Examples 1 to 4;

[0039] Figure 4 are XRD patterns of vanadium oxide films obtained according to the present application in Examples 2, 5 to 7;

[0040] Figure 5 are charge-discharge curves of batteries obtained according to the present application in Examples 1 to 4, wherein Figure 5 (a) is a charge-discharge curve of a battery obtained in Example 1, Figure 5 (b) is a charge-discharge curve of a battery obtained in Example 2, Figure 5 (c) is a charge-discharge curve of a battery obtained in Example 3, Figure 5 (d) is a charge-discharge curve of a battery obtained in Example 4;

[0041] Figure 6 are charge-discharge curves of batteries obtained according to the present application in Examples 2, 5 to 7, wherein Figure 6 (a) is a charge-discharge curve of a battery obtained in Example 5, Figure 6 (b) is a charge-discharge curve of a battery obtained in Example 6, Figure 6 (c) is a charge-discharge curve of a battery obtained in Example 2, Figure 6(d) is the charge-discharge curve of the battery obtained in Example 7;

[0042] Figure 7 is the rate capability plot of the battery obtained in accordance with Example 2 of the present application;

[0043] Figure 8 is the XPS spectrum of the vanadium oxide film obtained in accordance with Example 2 of the present application, wherein Figure 8 (a) is the XPS spectrum of the vanadium oxide film before charge-discharge, Figure 8 (b) is the XPS spectrum of the vanadium oxide film after discharge, Figure 8 (c) is the XPS spectrum of the vanadium oxide film after charge;

[0044] Figure 9 is the AC impedance plot of the battery obtained in accordance with Example 2 of the present application;

[0045] Figure 10 is the cyclic voltammogram of the battery obtained in accordance with Example 2 of the present application. DETAILED DESCRIPTION

[0046] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or like reference numerals represent the same or like elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0047] In one aspect of the present application, a method for preparing a positive electrode sheet is provided. According to an embodiment of the present application, the method comprises: sputtering a metal vanadium target by using a magnetron sputtering method and / or a pulsed laser sputtering method to deposit a vanadium oxide film on a conductive substrate, thereby obtaining a positive electrode sheet.

[0048] The method for preparing the positive electrode sheet according to the above-mentioned embodiments of the present application has at least the following beneficial effects: 1) The method can be used to prepare a positive electrode sheet with a layered or tunnel-like structure, which has a larger specific capacity and a higher electrode potential, and is suitable for ion deintercalation (especially zinc ion deintercalation), thereby helping to improve the specific capacity and stability of ion batteries (especially zinc ion batteries); 2) Vanadium oxide is deposited by the magnetron sputtering method and / or the pulsed laser sputtering method, which can effectively realize large-area film deposition, and the method has a simple process, low raw material cost and high safety, thereby facilitating large-scale industrial production; 3) Compared with vanadium oxide bulk, the structure of the vanadium oxide product prepared by the method is easier to control, and has high production stability; on the other hand, it is easier to quantitatively characterize, which helps to improve the accuracy and stability of the test results; on the other hand, it is more widely used, and can be assembled into a flexible zinc ion battery to realize more folding or curling functional applications; 4) The method can be used to conveniently control the phase composition of the vanadium oxide film, which is not only conducive to more comprehensive analysis of the electrochemical performance of vanadium oxide films with different compositions as positive electrode materials of aqueous zinc ion batteries, but also can adjust the composition of the vanadium oxide film according to different needs, thereby helping to increase the application range and use flexibility of the positive electrode sheet.

[0049] According to the embodiments of the present application, when the metal vanadium target is sputtered by the magnetron sputtering method and / or the pulsed laser sputtering method, the sputtering gas and oxygen can be introduced into the vacuum chamber of the sputtering equipment under the background vacuum degree. Under the condition of high voltage, the sputtering gas is ionized by discharge, and the generated sputtering ions bombard the metal vanadium target under the action of the electric field. Vanadium atoms are sputtered out and react with oxygen (reaction gas) to form a vanadium oxide film on the conductive substrate. The purity of the metal vanadium target can be not less than 99.99%, which helps to reduce the risk of introducing impurities and improve the purity of the vanadium oxide film. Further, by adjusting the oxygen partial pressure and / or reaction temperature during the reaction, the vanadium-oxygen atomic ratio of the vanadium oxide film formed on the conductive substrate can be changed, thereby obtaining vanadium oxide films with different phase compositions. Thus, it is not only conducive to more comprehensive analysis of the electrochemical performance of vanadium oxide films with different compositions as positive electrode materials of aqueous zinc ion batteries, but also can adjust the composition of the vanadium oxide film according to different needs, thereby helping to increase the application range and use flexibility of the positive electrode sheet.

[0050] According to the embodiments of the present application, the specific type of sputtering gas is not particularly limited in the present application, and can be flexibly selected by those skilled in the art according to the actual situation, for example, it can be argon. Since argon is low in price and easy to obtain, the production cost can be further controlled. Further, the purity of the sputtering gas can be not less than 99.99%, and the purity of the oxygen can be not less than 99.99%, which helps to further improve the purity of the vanadium oxide film obtained by sputtering.

[0051] According to the embodiment of the present application, the sputtering gas and oxygen can be introduced into the vacuum chamber of the sputtering device under a background vacuum degree of not greater than 4x10 -3 Pa, thereby more favorably improving the sputtering efficiency and the purity of the vanadium oxide film, and preferably the sputtering gas and oxygen can be introduced into the vacuum chamber of the sputtering device under a background vacuum degree of not greater than 7x10 -4 Pa. In addition, after the sputtering gas and oxygen are introduced into the vacuum chamber, the total gas pressure of the vacuum chamber can be 0.1-2 Pa. The inventor has found that if the total gas pressure of the vacuum chamber is too small, the sputtering gas cannot effectively bombard the vanadium target, and if the total gas pressure of the vacuum chamber is too large, deviation is prone to occur in the process of bombardment of the sputtering gas on the target, thereby affecting the sputtering efficiency. The present application controls the total gas pressure of the vacuum chamber in the above range, thereby favorably taking into account the deposition efficiency of vanadium oxide and the purity of the vanadium oxide film.

[0052] According to the embodiment of the present application, during sputtering, the reaction temperature can be controlled to be 25-500℃, for example, 50℃, 150℃, 250℃, 350℃ or 450℃, etc., and the oxygen partial pressure can be controlled to be 1-10%, for example, 2%, 4%, 6% or 8%, etc. The reaction temperature and the oxygen partial pressure have a certain degree of influence on the composition of the vanadium oxide film. In the present application, the reaction temperature and the oxygen partial pressure are controlled in the above range, and the vanadium oxide film can be deposited. The difference is only that the phase composition of the oxide film is different. For example, according to actual needs, the reaction temperature and the oxygen partial pressure can be flexibly adjusted in the given range, and the vanadium oxide film including at least one of V6O 13 , V2O5, V4O7 and VO2 can be obtained. In addition, the reaction temperature during sputtering is preferably 100-500℃, for example, 100-400℃ or 300-400℃, etc., and the oxygen partial pressure is preferably 2-5%, thereby more favorably improving the electrochemical performance of the vanadium oxide film positive electrode plate. According to some specific examples of the present application, when the reaction temperature is controlled to be 450-500℃ and the oxygen partial pressure is controlled to be 3-4% during sputtering, the vanadium oxide film including at least one of V2O5, V6O 13 , VO2 can be obtained; when the reaction temperature is controlled to be 300-400℃ and the oxygen partial pressure is controlled to be 3-4% during sputtering, the vanadium oxide film including V6O 13 and / or V2O5 can be obtained; when the reaction temperature is controlled to be 300-400℃ and the oxygen partial pressure is controlled to be 2-2.5% during sputtering, the vanadium oxide film including V4O7 and / or V2O5 can be obtained; and when the reaction temperature is controlled to be 180-250℃ and the oxygen partial pressure is controlled to be 3-4% during sputtering, the vanadium oxide film including VO2 can be obtained. It should be noted that in the present application, the reaction temperature can be provided by heating treatment of the conductive substrate, and the reaction temperature described in the present application can be understood as the temperature of the conductive substrate.

[0053] According to the embodiments of the present application, the vanadium oxide film can be deposited on at least one surface of the conductive substrate according to actual needs by using the magnetron sputtering method and / or the pulsed laser sputtering method, for example, when preparing the positive electrode sheet of the button cell, the vanadium oxide film can be deposited only on one surface of the conductive substrate; when preparing the positive electrode sheet of the stacked cell or the wound cell, the vanadium oxide film can be deposited on both opposite surfaces of the conductive substrate. In addition, the present application does not have special restrictions on the specific material of the conductive substrate, and the person skilled in the art can also select flexibly according to the actual situation, for example, it can be a metal material, a polymer material or an inorganic material, and further for example, it can be a flexible material, wherein the metal conductive substrate can be an aluminum foil, a copper foil, a 304 stainless steel sheet, a metal molybdenum sheet, etc., the polymer conductive substrate can be a conductive polymer film layer, and the inorganic conductive substrate can include but is not limited to transparent conductive glass. In addition, it also needs to be explained that when the prepared positive electrode sheet is used in a liquid cell, the positive electrode sheet with the vanadium oxide film deposited on one side is preferably stable with respect to the electrolyte, that is, it does not react with the electrolyte.

[0054] Further, according to some specific examples of the present application, the thickness of the conductive substrate can be not greater than 5 mm, for example, it can be 0.01 mm, 0.02 mm, 0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm or 4 mm, etc., and the thickness of the vanadium oxide film can be not less than 100 nm, for example, it can be not less than 200 nm, and specifically it can be 300 nm, 500 nm, 700 nm, 900 nm, 1.2 μm, 1.60 μm, 1.8 μm, 2 μm, 5 μm, 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, etc., thereby facilitating to improve the energy density of the cell assembled by the positive electrode sheet.

[0055] According to the embodiments of the present application, when the vanadium oxide film is deposited on the conductive substrate by using the magnetron sputtering method, the power density can be 1-3 W / cm 2 , the distance between the metal vanadium target and the conductive substrate can be 40-150 mm, and the sputtering time can be 0.5-10 h. By controlling the magnetron sputtering conditions within the above range, vanadium oxide films with different thicknesses can be deposited on the conductive substrate. In addition, according to some specific examples of the present application, before depositing the vanadium oxide film on the conductive substrate, it can further include: pre-sputtering treatment of the target. By pre-sputtering treatment, the surface of the metal vanadium target can be cleaned to remove oxides and attached impurities on the surface of the metal vanadium target, thereby facilitating to improve the purity of the vanadium oxide film. Further, the present application does not have special restrictions on the pre-sputtering time, and the person skilled in the art can select flexibly according to the actual situation, for example, the pre-sputtering treatment time can be 10-30 min, thereby further ensuring that the surface of the metal vanadium target is kept clean before sputtering.

[0056] According to an embodiment of the present application, when depositing a vanadium oxide film on a conductive substrate by means of pulsed laser sputtering, the energy density can be 1-2 J / cm 2 The frequency can be 3-8 Hz, the distance between the vanadium metal target and the conductive substrate can be 40-70 mm, and the sputtering duration can be 0.5-10 h, for example, 1 h, 2 h, 4 h, 6 h or 8 h, etc. By controlling the conditions of pulsed laser sputtering within the above ranges, a vanadium oxide film can be deposited on the conductive substrate.

[0057] In still another aspect of the present application, the present application provides a positive electrode plate prepared by the above method. The features and effects described for the method of preparing the positive electrode plate also apply to the positive electrode plate, which will not be described here again. In general, the positive electrode plate not only has good electrochemical stability and high specific capacity, but also has a simple preparation process and a wide range of applications.

[0058] In still another aspect of the present application, the present application provides a battery, according to an embodiment of the present application, the battery comprises the above-mentioned positive electrode plate, and / or the positive electrode plate prepared by the above-mentioned method. The features and effects described for the positive electrode plate and the method of preparing the positive electrode plate also apply to the battery, which will not be described here again. In general, compared with the prior art, the battery not only has a lower manufacturing cost, but also can balance high specific capacity and good electrochemical stability.

[0059] According to an embodiment of the present application, the battery can be an aqueous zinc ion battery, which has a low manufacturing cost, a high energy density, a good stability and a high safety, and has a good application prospect due to the abundant zinc reserves. In addition, the shape of the battery is not particularly limited in the present application, and a person skilled in the art can select it flexibly according to the actual situation, for example, it can be a button cell, a stacked cell or a wound cell, etc.

[0060] Embodiments of the present application will be described in detail below. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. If the specific technology or condition is not specified in the embodiments, it is carried out according to the technology or condition described in the literature in the art or according to the product manual. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0061] Example 1

[0062] (1) A vanadium metal target with a diameter of 54 mm and a purity of not less than 99.99% was sputtered by means of magnetron sputtering, and the vacuum chamber of the sputtering equipment was pumped to less than 7x10 -4Pa, and pure argon and oxygen with a purity of 99.999% were introduced again, the total gas pressure in the vacuum chamber was controlled to be 0.2 Pa, the oxygen partial pressure was 2.5%, the reaction temperature was 400°C, the sputtering current was 0.1 A, the sputtering power was (40±5) W, the sputtering time was 2 h, and a vanadium oxide film with a thickness of 259 nm was deposited on a 304 stainless steel sheet to obtain a positive electrode sheet;

[0063] (2) Another piece of vanadium oxide film was placed in a zinc sulfate electrolyte with a concentration of 1 mol / L, and after saturation, it was filtered to obtain an electrolyte saturated with vanadium oxide;

[0064] (3) The negative electrode sheet was selected to be a zinc sheet, which was slightly polished with sandpaper to remove oxides, and the film substrate and other battery accessories were ultrasonically cleaned with a Decon90 alkaline cleaning solution with a concentration of 3-5 wt%, deionized water, and anhydrous ethanol for 1 h, and the ultrasonic power was 50-90 W, and then dried with a nitrogen gun for standby, and then the positive electrode sheet, the electrolyte, and the negative electrode sheet were assembled to obtain a water-based zinc ion battery.

[0065] Example 2

[0066] The difference from Example 1 is that in step (1), the oxygen partial pressure is 3%.

[0067] Example 3

[0068] The difference from Example 1 is that in step (1), the oxygen partial pressure is 3.5%.

[0069] Example 4

[0070] The difference from Example 1 is that in step (1), the oxygen partial pressure is 4%.

[0071] Example 5

[0072] The difference from Example 1 is that in step (1), the reaction temperature is 200°C.

[0073] Example 6

[0074] The difference from Example 1 is that in step (1), the reaction temperature is 300°C.

[0075] Example 7

[0076] The difference from Example 1 is that in step (1), the reaction temperature is 500°C.

[0077] Testing and characterization

[0078] Under the same test conditions, the vanadium oxide films obtained in Examples 1-7 were subjected to SEM analysis, and the test results are shown in Table 1. Figures 1-2

[0079] ​The vanadium oxide films obtained in Examples 1-7 were subjected to XRD analysis under the same test conditions, and the test results are shown in Table 2. Figures 3-4

[0080] The batteries obtained in Examples 1-7 were subjected to charge-discharge test in the voltage range of 0.4-1.4 V under the same test conditions, and the test results are shown in Table 3. Figures 5-6

[0081] The battery obtained in Example 2 was subjected to rate performance analysis, and the test results are shown in Table 4. Figure 7

[0082] The vanadium oxide film obtained in Example 2 was subjected to XPS analysis, and the test results are shown in Table 5. Figure 8

[0083] The battery obtained in Example 2 was subjected to AC impedance analysis, and the test results are shown in Table 6. Figure 9

[0084] The battery obtained in Example 2 was subjected to cyclic voltammetry characterization, and the test results are shown in Table 7. Figure 10

[0085] Results and Discussion

[0086] The SEM images of the vanadium oxide films obtained in Examples 1-7 are shown in Table 8. Figures 1-2 As can be seen, the vanadium oxide film obtained in Example 2 (oxygen partial pressure of 3%, reaction temperature of 400°C) has higher crystallinity and obvious channel structure, which is helpful for the deintercalation of zinc ions.

[0087] The XRD patterns of the vanadium oxide films obtained in Examples 1-7 are shown in Table 9. Figures 3-4 As can be seen, the vanadium oxide films obtained in Examples 1-7 are composed of at least one of VO2, V6O 13 , V2O5 and V4O7. Among them, when the reaction temperature is 400°C: the vanadium oxide film is mainly composed of V6O 13 and V2O5 when the oxygen partial pressure is 3% (Example 2) or the oxygen partial pressure is 4% (Example 4); the vanadium oxide film is mainly composed of V2O5 and V4O7 when the oxygen partial pressure is 2.5% (Example 1); the vanadium oxide film is mainly composed of V2O5 when the oxygen partial pressure is 3.5% (Example 3); the vanadium oxide film is mainly composed of V2O5, V6O 13 and VO2 when the oxygen partial pressure is 3% and the reaction temperature is 500°C (Example 7); the vanadium oxide film is mainly composed of V2O5 and V6O 13 ​​​​​​; when the reaction temperature is 200°C (Example 5), the main component of the vanadium oxide film is V2O5. Among them, the vanadium oxide film obtained in Example 2 has main diffraction peaks at positions of 17.8°, 26.8°, 36°, 45.5° and 55.3°, which respectively match the (002), (003), (004), (005) and (006) crystal faces of V6O 13 .

[0088] The charge-discharge curves of the batteries obtained in Examples 1-7 in the voltage range of 0.4-1.4 V are shown in Figures 5-6 . It can be seen that the battery prepared in Example 2 has a higher specific capacity, which can reach 350 mAh / g, and the capacity retention rate after 50 cycles is 62.67%, which is due to the fact that the main component of the vanadium oxide film obtained in Example 2 is V6O 13 , which has a single-double layer alternating channel structure, which is more conducive to the insertion and extraction of zinc ions.

[0089] The rate performance graph of the battery obtained in Example 2 is shown in Figure 7 . It can be seen that at current densities of 0.2C, 0.5C, 1C, 2C, 3C and 5C, the discharge specific capacity of the battery is 350 mAh / g, 270 mAh / g, 213 mAh / g, 150 mAh / g, 121 mAh / g and 89 mAh / g, respectively. And when the charge-discharge current density is restored from 5C to 0.2C, the specific capacity of the battery is restored to 345 mAh / g, indicating that the aqueous zinc ion battery with a vanadium oxide film as the positive electrode has good stability.

[0090] The XPS energy spectrum of the vanadium oxide film obtained in Example 2 as the positive electrode of the battery before and after charge-discharge is shown in Figure 8 . It can be seen that the treated vanadium oxide film sample corresponds to V(2p 1 / 2 ) and V(2p 3 / 2 ) in three valence states of trivalent, tetravalent and pentavalent, respectively. Specifically, Figure 8 (a) is the XPS energy spectrum of the vanadium oxide film before charge-discharge, and after data analysis, the bond energy is 516.5 eV, 523.7 eV and 517.3 eV, 524.5 eV, which corresponds to the peak values of tetravalent and pentavalent vanadium, and the composition of the vanadium oxide film before charge-discharge can be obtained as V6O 13 and V2O5; Figure 8 (b) is the XPS energy spectrum of the discharged vanadium oxide film, and the bond energy is 515.6 eV, 522.8 eV and 517.3 eV, 524.5 eV, which respectively corresponds to trivalent and tetravalent vanadium oxide, so it can be known that the vanadium ions are reduced from pentavalent and tetravalent to tetravalent or trivalent when the vanadium oxide film is discharged; Figure 8(c) is the XPS spectrum of the charged vanadium oxide film, which contains vanadium ions of valence four and five, and Figure 8 (a) and (b) can be compared, after charging the battery, vanadium ions are mostly oxidized to valence five. The change of valence state of vanadium ions before and after charging and discharging reflects the deintercalation of zinc ions in the positive electrode of the battery.

[0091] The AC impedance spectrum of the battery obtained in Example 2 is shown in Figure 9 , wherein the impedance of the electrolyte is about 100 Ω. The size of the resistance reflects the rate of zinc ion diffusion, and the resistance of the battery is relatively small.

[0092] The cyclic voltammogram of the battery obtained in Example 2 is shown in Figure 10 , which has two pairs of redox peaks, 0.43V / 0.93V and 0.94V / 1.16V, respectively. Corresponding Figure 8 to the change of valence state of vanadium ions in vanadium oxide, wherein 0.43V / 0.93V corresponds to the change of valence state of V 3+ / V 4+ , and 0.94V / 1.16V corresponds to the change of valence state of V 4+ / V 5+ . This indicates that zinc ions in the battery are deintercalated and cause redox reaction of vanadium oxide.

[0093] In summary, the positive electrode sheet prepared by the above method can conveniently control the phase composition of the vanadium oxide film, which is not only conducive to more comprehensive analysis of the electrochemical performance of vanadium oxide films of different compositions as positive electrode materials of aqueous zinc ion batteries, but also can adjust the composition of the vanadium oxide film according to different needs, which is conducive to increasing the application range and use flexibility of the positive electrode sheet.

[0094] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0095] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that variations, modifications, substitutions and changes can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A battery, characterized by, The method for preparing the battery comprises: (1) using magnetron sputtering method on the diameter of 54 mm, purity of not less than 99.99% of metal vanadium target material sputtering, sputtering equipment vacuum chamber pressure to less than 7*10 -4 Pa, again into the purity of 99.999% argon and oxygen, control the total gas pressure in the vacuum chamber is 0.2 Pa, oxygen partial pressure is 3%, the reaction temperature is 400 DEG C, sputtering current is 0.1 A, sputtering power is 35-45 W, sputtering duration is 2 h, on the 304 stainless steel sheet deposited thickness of 259 nm vanadium oxide film, get the positive electrode plate; (2) Another piece of vanadium oxide film is placed into a zinc sulfate electrolyte with a concentration of 1 mol / L, and after saturation, the vanadium oxide saturated electrolyte is obtained by filtration; (3) The negative electrode sheet is selected from zinc sheets, and the oxide is removed by slightly polishing with sandpaper; the film substrate and other accessories of the battery are subjected to ultrasonic cleaning treatment for 1 h each using a Decon90 alkaline cleaning solution with a concentration of 3-5 wt%, deionized water and anhydrous ethanol, and the ultrasonic power is 50-90 W; then the negative electrode sheet is obtained by blowing dry with a nitrogen gun for standby; the positive electrode sheet obtained in step (1), the electrolyte obtained in step (2) and the negative electrode sheet obtained in step (3) are assembled to obtain the aqueous zinc ion battery; The vanadium oxide film includes V6O 13 and V2O5.

2. The battery of claim 1, wherein, Before depositing the vanadium oxide film, the target material is subjected to a pre-sputtering treatment.

3. The battery of claim 2, wherein, The duration of the pre-sputtering treatment of the target material is 10-30 min.

4. The battery of claim 1, wherein, The battery is a button cell, a stacked cell or a rolled cell.

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