Zinc ion battery positive plate, aqueous zinc ion battery and application

Abstract

The invention relates to a zinc ion battery positive plate, a water-based zinc ion battery and application, zinc ferrite as a common material is low in price, simple in manufacturing technology and easy to obtain on a large scale, and the battery manufactured by using the zinc ferrite as the positive electrode material of the water-based zinc ion battery has high specific capacity and good cycle stability. Meanwhile, the invention also provides a water-based zinc ion battery prepared by taking zinc ferrite as the positive electrode material, the water-based zinc ion battery has the characteristics of high safety, long cycle life and large capacity, the specific discharge capacity of the battery is up to 328mAh / g under the current density of 50mA / g, the battery keeps good reversible charge-discharge performance, the coulombic efficiency is close to 100%, and the specific discharge capacity of 70mAh / g can still be kept after 100 cycles. Therefore, the aqueous zinc ion battery taking the zinc ferrite as the positive electrode material has a wide application prospect in the aspects of a high-safety standby power supply and large-scale energy storage.

Description

Technical Field

[0001] The present application relates to the technical field of zinc-ion batteries, in particular to a positive electrode sheet for zinc-ion batteries, an aqueous zinc-ion battery, and applications thereof. Background Art

[0002] With the development of technology and the increasingly serious energy problems, safe, environmentally friendly, and low-cost energy storage devices have become the best choice for people. Although there are a wide variety of battery types on the market currently, none of them can fully meet the needs of the energy storage market, and most types of batteries still have problems such as high price, short lifespan, and insufficient safety. Aqueous ion energy storage batteries use a neutral saline solution as the electrolyte, which not only avoids the flammability problem of organic electrolytes but also overcomes the disadvantages of traditional aqueous batteries, such as high pollution, short lifespan (such as lead-acid batteries), and high cost (nickel-metal hydride batteries). It is an ideal system that can meet the requirements of large-scale energy storage technology. As a highly safe battery, aqueous zinc-ion batteries have attracted much attention due to the high abundance of zinc, the safety of the electrolyte, and the low redox potential / high theoretical specific capacity.

[0003] For the positive electrode materials of aqueous energy storage batteries, most of the electrode materials are metal oxide semiconductors, such as manganese oxide, vanadium oxide, etc. The main defects are as follows: On the one hand, to increase the specific capacity of the electrode material, it is necessary to increase the specific surface area of the electrode material so that the electrode material can contact the electrolyte solution as much as possible, thereby more fully undergoing redox reactions and storing more charges. However, the huge specific surface area will also introduce a large number of surface state energy levels caused by the material surface. The existence of these surface state energy levels may affect the electron transport and storage, thereby affecting the specific capacity of the electrode material and the self-discharge performance of the device. Summary of the Invention

[0004] Based on this, the purpose of the present application includes providing a positive electrode sheet for a zinc-ion battery whose active material includes zinc ferrite.

[0005] The technical solution of the present application is as follows:

[0006] In the first aspect of the present invention, there is provided a positive electrode sheet for a zinc-ion battery, the positive electrode sheet for a zinc-ion battery includes a positive electrode active layer, and the active material of the positive electrode active layer includes zinc ferrite.

[0007] In one embodiment, the chemical formula of the zinc ferrite is ZnFe₂O₄.

[0008] In one embodiment, the particle size of the zinc ferrite is 100 nanometers to 1000 nanometers.

[0009] In one embodiment, the positive electrode active layer further includes a conductive agent and a binder;

[0010] Optionally, the conductive agent is carbon black and the binder is PVDF.

[0011] In one embodiment, in the zinc ion positive electrode sheet, the mass ratio of zinc ferrite, carbon black conductive agent and PVDF binder is (6 - 7):(2 - 3):(1 - 2).

[0012] In one embodiment, the zinc ion battery includes an aqueous zinc ion battery.

[0013] In a second aspect of the present invention, there is provided an aqueous zinc ion battery, and the preparation raw materials of the aqueous zinc ion battery include a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte;

[0014] The positive electrode sheet is selected from the zinc ion battery positive electrode sheet as described above.

[0015] In one embodiment, the negative electrode sheet includes metallic zinc; and / or

[0016] The separator is at least one of glass fiber and polypropylene.

[0017] In one embodiment, the electrolyte includes an aqueous solution of zinc sulfate or an aqueous solution of zinc trifluoromethanesulfonate.

[0018] In a third aspect of the present invention, there is provided the use of zinc ferrite in the preparation of a positive electrode material for an aqueous zinc ion battery.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application provides the use of zinc ferrite in the preparation of a positive electrode material for an aqueous zinc ion battery. As a common material, zinc ferrite is inexpensive, has a simple manufacturing technique, and is easy to obtain on a large scale. Using zinc ferrite as the positive electrode material of an aqueous zinc ion battery, the fabricated battery has a high specific capacity and good cycle stability.

[0021] Meanwhile, the present application also provides an aqueous zinc ion battery fabricated with zinc ferrite as the positive electrode material, which has the characteristics of high safety, long cycle life and large capacity. At a current density of 50 mA / g, the battery discharge specific capacity is as high as 328 mAh / g, the battery maintains good reversible charge and discharge performance, the Coulomb efficiency is close to 100%, and the discharge specific capacity of 70 mAh / g can still be maintained after 100 cycles. Therefore, the aqueous zinc ion battery with zinc ferrite as the positive electrode material has broad application prospects in high - safety backup power supplies and large - scale energy storage. Description of the Drawings

[0022] To more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 This is the XRD pattern of ZnFe2O4 in the present application.

[0024] Figure 2 This is the TEM image of ZnFe2O4 in the present application.

[0025] Figure 3 These are the charge-discharge curve and cycling curve of the battery in Example 1 of the present application at a current density of 50 mA / g.

[0026] Figure 4 These are the charge-discharge curve and cycling curve of the battery in Example 2 of the present application at a current density of 500 mA / g.

[0027] Figure 5 This is the charge-discharge curve of the battery in Example 3 of the present application.

[0028] Figure 6 This is the charge-discharge curve of the battery in Example 4 of the present application.

[0029] Figure 7 These are the charge-discharge curves of the batteries in Example 2 and Comparative Example 1 of the present application.

[0030] Figure 8 These are the charge-discharge curves of the batteries in Example 5 and Comparative Example 2 of the present application. Specific Embodiments

[0031] To make the above objects, features, and advantages of the present application more clearly understandable, the following will provide a detailed description of the specific embodiments of the present application. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0033] Unless otherwise specified or there is a contradiction, the terms or phrases used in this document have the following meanings:

[0034] In this application, "one or more" means any one, any two, or any two or more of the listed items.

[0035] In this application, the optional scope of "and / or", "or / and", and "and / or" includes any one of two or more related listed items, and also includes any and all combinations of the related listed items. The said any and all combinations include any two related listed items, any more related listed items, or the combination of all related listed items. (It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, this technical solution undoubtedly includes the technical solution connected by "logical AND", and also undoubtedly includes the technical solution connected by "logical OR". For example, "A and / or B" includes three parallel solutions: A, B, and A + B. Another example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, it includes the combination of any two or any three of A, B, C, and D, and also includes the four-item combination of A, B, C, and D (that is, the technical solution connected by "logical AND").)

[0036] In this application, terms such as "further", "even further", and "especially" are used for descriptive purposes, indicating differences in content, but should not be construed as limiting the scope of protection of this application.

[0037] In this application, in "the first aspect", "the second aspect", "the third aspect", etc., the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or quantity, nor can it be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", etc. only serve the purpose of non-exhaustive listing and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0038] In this application, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when the range refers to integers, it includes every integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0039] The present application discloses only some numerical ranges specifically. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, and any upper limit can be combined with any other upper limit to form an undefined range. In addition, each separately disclosed point or single value itself can be combined with any other point or single value as a lower limit or upper limit or with other lower limits or upper limits to form an undefined range. The use of numerical ranges represented by endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0040] The percentage contents involved in this application, unless otherwise specified, refer to mass percentage for solid-liquid mixing and solid-solid mixing, and refer to volume percentage for liquid-liquid mixing.

[0041] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0042] The temperature parameters in this application, unless otherwise specified, allow both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±2°C, ±1°C, ±0.5°C, ±0.4°C, ±0.3°C, ±0.2°C, and ±0.1°C are allowed. Normal temperature or room temperature in this application refers to no temperature control operation, generally 4°C to 35°C, preferably 20±5°C.

[0043] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0044] Aqueous zinc-ion batteries (AZIBs) are a type of secondary battery technology that uses aqueous solution as electrolyte, zinc metal or zinc compound as negative electrode, and material that can embed / de-embed zinc ions as positive electrode. With the advantages of high safety, low cost, and environmental friendliness, aqueous zinc-ion batteries have shown broad application prospects in large-scale energy storage, portable electronic devices and other fields. The selection of positive electrode materials for aqueous zinc-ion batteries (AZIBs) needs to comprehensively consider factors such as energy density, cycle stability, cost and environmental friendliness. The current mainstream positive electrode materials include manganese-based materials, vanadium-based materials and Prussian blue analogs. The selection of positive electrode materials for aqueous zinc-ion batteries needs to balance performance and cost according to specific application scenarios.

[0045] Zinc ferrite is a composite metal oxide with a spinel structure, with the chemical formula ZnFe2O4. It belongs to the typical spinel-type ferrite, having both ferromagnetic, semiconductor, and catalytic activities, and has a wide range of applications in the fields of materials science, environmental science, energy technology, etc. As a common material, zinc ferrite is inexpensive, has a simple manufacturing technology, and is easy to obtain on a large scale. Therefore, the aqueous zinc-ion battery using zinc ferrite as the positive electrode material has broad application prospects in high-security backup power supplies and large-scale energy storage. Based on this, the technical personnel of this application provided an application of zinc ferrite as the positive electrode material of an aqueous zinc-ion battery after a large amount of research. The aqueous zinc-ion battery using zinc ferrite as the positive electrode material has the characteristics of high safety, long cycle life, and large capacity.

[0046] In the first aspect of the present invention, a positive electrode sheet for a zinc-ion battery is provided. The positive electrode sheet for the zinc-ion battery includes a positive electrode active layer, and the active material of the positive electrode active layer includes zinc ferrite.

[0047] In one embodiment, the chemical formula of the zinc ferrite is ZnFe2O4.

[0048] In one embodiment, the particle size of the zinc ferrite is 100 nanometers to 1000 nanometers. It can be understood that the particle size of the zinc ferrite includes but is not limited to 100 nanometers, 150 nanometers, 200 nanometers, 250 nanometers, 300 nanometers, 350 nanometers, 400 nanometers, 450 nanometers, 500 nanometers, 550 nanometers, 600 nanometers, 650 nanometers, 700 nanometers, 750 nanometers, 800 nanometers, 850 nanometers, 900 nanometers, 950 nanometers, 1000 nanometers. Further, the particle size of the zinc ferrite is 350 nanometers to 800 nanometers.

[0049] In one embodiment, the positive electrode active layer further includes a conductive agent and a binder.

[0050] In some examples, in the positive electrode sheet for zinc ions, the mass ratio of zinc ferrite, carbon black conductive agent, and PVDF binder is (6 to 7):(2 to 3):(1 to 2). It can be understood that in the positive electrode sheet, the mass ratio of zinc ferrite, conductive agent, and binder includes but is not limited to 6:2:1, 7:2:1, 6:3:1, 7:3:1, 6:2:2, 7:2:2, 6:3:2, 7:3:2.

[0051] In some examples, the conductive agent is selected from carbon black conductive agents.

[0052] In some examples, the binder is selected from PVDF binders.

[0053] In some examples, the zinc-ion battery includes an aqueous zinc-ion battery.

[0054] In a second aspect of the present invention, a water-based zinc-ion battery is provided. The raw materials for preparing the water-based zinc-ion battery include a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte solution;

[0055] The positive electrode sheet is selected from the positive electrode sheets of the zinc-ion batteries as described above.

[0056] In some examples, the negative electrode sheet includes metallic zinc.

[0057] In some examples, the separator is at least one of glass fiber and polypropylene.

[0058] In some examples, the electrolyte solution is selected from an aqueous solution of zinc sulfate or an aqueous solution of zinc trifluoromethanesulfonate.

[0059] In some examples, the concentration of the aqueous solution of zinc sulfate is 0.5 mol / L to 5 mol / L. Further, the concentration of the aqueous solution of zinc sulfate is 1 mol / L to 3 mol / L. It can be understood that the concentration of the aqueous solution of zinc sulfate includes but is not limited to 1 mol / L, 1.25 mol / L, 1.5 mol / L, 1.75 mol / L, 2 mol / L, 2.25 mol / L, 2.5 mol / L, 2.75 mol / L, 3 mol / L.

[0060] In some examples, the concentration of the aqueous solution of zinc trifluoromethanesulfonate is 0.5 mol / L to 5 mol / L. Further, the concentration of the aqueous solution of zinc trifluoromethanesulfonate is 1 mol / L to 3 mol / L. It can be understood that the concentration of the aqueous solution of zinc trifluoromethanesulfonate includes but is not limited to 1 mol / L, 1.25 mol / L, 1.5 mol / L, 1.75 mol / L, 2 mol / L, 2.25 mol / L, 2.5 mol / L, 2.75 mol / L, 3 mol / L.

[0061] In summary, the present application uses zinc ferrite as the positive electrode material of the water-based zinc-ion battery. The prepared water-based zinc-ion battery has the characteristics of high safety, long cycle life, and large capacity. At a current density of 50 mA / g, the discharge specific capacity of the battery is as high as 328 mAh / g. The battery maintains good reversible charge and discharge performance, and the coulombic efficiency is close to 100%. After 100 cycles, the discharge specific capacity of 70 mAh / g can still be maintained. When the current increases to 500 mA / g, the discharge specific capacity of the battery can still reach 215 mAh / g. At the same time, compared with the same type of technology, zinc ferrite is a common material, with low price, simple manufacturing technology, and easy to obtain on a large scale. Using zinc ferrite as the positive electrode material of the water-based zinc-ion battery, the prepared battery has a high specific capacity and good cycle stability.

[0062] The following is a further illustration in combination with specific embodiments. For the raw materials involved in the following specific embodiments, unless otherwise specified, they can all be obtained commercially; for the instruments used, unless otherwise specified, they can all be obtained commercially; for the processes involved, unless otherwise specified, they are all the conventional choices of those skilled in the art.

[0063] The preparation method of zinc ferrite adopted in the examples is as follows: Dissolve 2.5 mmol of zinc chloride and 5 mmol of ferric chloride in 50 mL of ethylene glycol, then add 3.6 g of sodium acetate and 1 g of polyethylene glycol. After continuous stirring and dissolution, transfer it to a 200 mL reaction kettle and place it in an electrothermal constant temperature blast furnace for heating at 150 °C - 200 °C for 4 h - 10 h. The obtained reaction product is washed and centrifuged repeatedly, and then dried in an oven at 60 °C for 6 h - 12 h. The XRD pattern and TEM pattern are as Figure 1 and Figure 2 shown.

[0064] The following are specific embodiments.

[0065] Example 1

[0066] Use zinc ferrite with an average particle size of 350 nanometers as the positive electrode material, and mix it according to the mass ratio of zinc ferrite: carbon black conductive agent: PVDF binder = 7:2:1. After grinding and dispersing, uniformly coat it on a 500-mesh stainless steel mesh, and obtain a positive electrode sheet after drying. Use a metal zinc sheet as the negative electrode sheet, glass fiber as the separator, and use a 2 mol / L zinc sulfate aqueous solution as the electrolyte to assemble a 2032-type button aqueous zinc ion battery, and conduct electrochemical charge and discharge performance tests at a current density of 50 mA / g. The charge-discharge curve and cycle curve are as Figure 3 shown.

[0067] Example 2

[0068] Use zinc ferrite with an average particle size of 800 nanometers as the positive electrode material, and mix it according to the mass ratio of zinc ferrite: carbon black conductive agent: PVDF binder = 7:2:1. After grinding and dispersing, uniformly coat it on a 500-mesh stainless steel mesh, and obtain a positive electrode sheet after drying. Use a metal zinc sheet as the negative electrode sheet, glass fiber as the separator, and use a 3 mol / L zinc trifluoromethanesulfonate aqueous solution as the electrolyte to assemble a 2032-type button aqueous zinc ion battery, and conduct electrochemical charge and discharge performance tests at a current density of 500 mA / g. The charge-discharge curve and cycle curve are as Figure 4 shown.

[0069] Example 3

[0070] Zinc ferrite with an average particle size of 500 nanometers was used as the positive electrode material, and it was mixed according to the mass ratio of zinc ferrite: carbon black conductive agent: PVDF binder = 6:3:1. After grinding and dispersing, it was evenly coated on a 500-mesh stainless steel mesh, and the positive electrode sheet was obtained after drying. A metal zinc sheet was used as the negative electrode, glass fiber was used as the separator, and the electrolyte was an aqueous solution of zinc sulfate with a concentration of 3 mol / L. A 2032-type button aqueous zinc ion battery was assembled and subjected to an electrochemical charge-discharge performance test at a current density of 100 mA / g. The charge-discharge curve is as Figure 5 shown.

[0071] Example 4

[0072] Zinc ferrite with an average particle size of 100 nanometers was used as the positive electrode material, and it was mixed according to the mass ratio of zinc ferrite: carbon black conductive agent: PVDF binder = 6:3:1. After grinding and dispersing, it was evenly coated on a 500-mesh stainless steel mesh, and the positive electrode sheet was obtained after drying. A metal zinc was used as the negative electrode sheet, glass fiber was used as the separator, and the electrolyte was an aqueous solution of zinc trifluoromethanesulfonate with a concentration of 3 mol / L. A 2032-type button aqueous zinc ion battery was assembled and subjected to an electrochemical charge-discharge performance test at a current density of 100 mA / g. The charge-discharge curve is as Figure 6 shown.

[0073] Example 5

[0074] Zinc ferrite with an average particle size of 500 nanometers was used as the positive electrode material, and it was mixed according to the mass ratio of zinc ferrite: carbon black conductive agent: PVDF binder = 6:2:2. After grinding and dispersing, it was evenly coated on a 500-mesh stainless steel mesh, and the positive electrode sheet was obtained after drying. A metal zinc was used as the negative electrode sheet, glass fiber was used as the separator, and the electrolyte was an aqueous solution of zinc sulfate with a concentration of 2 mol / L. A 2032-type button aqueous zinc ion battery was assembled and subjected to an electrochemical charge-discharge performance test at a current density of 500 mA / g. The charge-discharge curve is as Figure 8 shown.

[0075] Figure 3 On the left is the charge-discharge curve of the battery in Example 1, and on the right is the cycle curve. From Figure 3 it can be seen that at a current density of 50 mA / g, the initial discharge specific capacity of the battery device can reach 328 mAh / g, the Coulomb efficiency is close to 100%, and the discharge specific capacity of 70 mAh / g can still be maintained after 100 cycles.

[0076] Figure 4 On the left is the charge-discharge curve of the battery in Example 2, and on the right is the cycle curve. From Figure 4It can be seen that at a current density of 500 mA / g, the initial discharge specific capacity of the battery device can reach 215 mAh / g, the coulombic efficiency is close to 100%, and the discharge specific capacity of 25 mAh / g can still be maintained after 100 cycles.

[0077] Figure 5 is the charge-discharge curve of the battery of Example 3. As can be seen from Figure 5 it, at a current density of 100 mA / g, the initial discharge specific capacity of the battery device can reach 300 mAh / g.

[0078] Figure 6 is the charge-discharge curve of the battery of Example 4. As can be seen from the figure, at a current density of 100 mA / g, the initial discharge specific capacity of the battery device can reach 211 mAh / g.

[0079] The above results show that by using zinc ferrite with different sizes as the battery cathode material and electrolytes with different concentrations and types, the highest specific capacity of the battery can easily exceed 300 mAh / g; secondly, when charging and discharging with different currents, the coulombic efficiency of the battery charging and discharging is close to 100%.

[0080] Comparative Example 1

[0081] The preparation method of Comparative Example 1 is basically the same as that of Example 2, and the main difference is that the cathode material zinc ferrite is replaced with magnetite, and other conditions are the same as those of Example 2.

[0082] The electrochemical charge-discharge performance tests of Comparative Example 1 and Example 2 were carried out again under the same conditions, and the results are as Figure 7 shown. As can be seen from Figure 7 the results, for the energy storage battery prepared according to the conditions of Example 2, at a current density of 500 mA / g, the initial discharge specific capacity of the battery can reach 221 mAh / g (the measurement error between this test result and Figure 4 the data shown is 2.79%, which is within the standard allowable error range), and the coulombic efficiency is close to 100%. For the battery prepared under the conditions of Comparative Example 1, at the same current density, the initial discharge specific capacity of the battery is only 155 mAh / g, and the coulombic efficiency is lower than that of Example 2. Moreover, within 100 charge-discharge cycles of the battery, the specific capacity of the battery in Example 2 is always higher than that in Comparative Example 1.

[0083] Comparative Example 2

[0084] The preparation method of Comparative Example 2 is basically the same as that of Example 5, and the main difference is that the cathode material zinc ferrite is replaced with iron oxide, and other conditions are the same as those of Example 5.

[0085] The electrochemical charge-discharge performance test results of Example 5 and Comparative Example 2 are as Figure 8As shown in the figure. Starting from Figure 8 From the results, the energy storage battery fabricated under the conditions of Example 5 has an initial discharge specific capacity of up to 160 mAh / g at a current density of 500 mA / g, and the coulombic efficiency is close to 99%. For the battery fabricated under the conditions of Comparative Example 2, at the same current density, the initial discharge specific capacity of the battery is only 47 mAh / g, and the coulombic efficiency is lower than that of Example 2. Moreover, within 100 charge-discharge cycles, the specific capacity of the battery in Example 5 is always higher than that in Comparative Example 2.

[0086] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0087] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can be made, and these all belong to the protection scope of the present application. In addition, it should be understood that after reading the above teachings of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the technical solutions provided in the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. A zinc ion battery positive electrode sheet, characterized in that: The zinc ion battery positive electrode sheet comprises a positive electrode active layer, and the active material of the positive electrode active layer comprises zinc ferrite.

2. The zinc ion battery positive electrode sheet according to claim 1, characterized in that: The chemical formula of zinc ferrite is ZnFe2O4.

3. The zinc ion battery positive electrode sheet according to claim 1, characterized in that: The particle size of the zinc ferrite is 100 nanometers to 1000 nanometers.

4. The zinc ion battery positive electrode sheet according to claim 1, characterized in that: The positive electrode active layer also includes a conductive agent and a binder; Optionally, the conductive agent is carbon black, and the adhesive is PVDF.

5. The zinc ion battery positive electrode sheet according to claim 4, characterized in that: In the zinc ion positive electrode sheet, the mass ratio of zinc ferrite, conductive agent and adhesive is (6-7): (2-3): (1-2).

6. The zinc ion battery positive electrode sheet according to claim 1, characterized in that: The zinc ion battery comprises an aqueous zinc ion battery.

7. An aqueous zinc ion battery, characterized in that: The raw materials for preparing the aqueous zinc ion battery include a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte; The positive electrode sheet is selected from the positive electrode sheet of a zinc ion battery according to any one of claims 1 to 6.

8. The aqueous zinc ion battery according to claim 7, characterized in that: The negative electrode sheet comprises metallic zinc; and / or The separator is at least one of glass fiber and polypropylene.

9. The aqueous zinc ion battery according to claim 7, characterized in that: The electrolyte includes an aqueous solution of zinc sulfate or an aqueous solution of zinc trifluoromethanesulfonate.

10. Application of zinc ferrite in the preparation of positive electrode materials for aqueous zinc ion batteries.

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