Oxygen vacancy-rich potassium-zinc vanadate ion battery positive electrode material and preparation method and application thereof

Abstract

The invention relates to an oxygen vacancy-enriched potassium vanadate zinc ion battery positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of aqueous zinc ion battery positive electrode materials. In order to solve the problem that oxygen vacancies introduced into a positive electrode material V2O5 are unstable in the battery circulation process, the invention provides an oxygen vacancy-enriched potassium-zinc vanadate ion battery positive electrode material which is potassium ion doped hydrated vanadium pentoxide. The high-stability oxygen-vacancy-enriched potassium vanadate zinc ion battery positive electrode material is obtained by accurately regulating and controlling the doping concentration and preparation process parameters, and the stability and the electrochemical performance of the material in the circulation process and the diffusion kinetics of zinc ions are improved. When the material is applied to the aqueous zinc ion battery, the material shows relatively high energy density and power density and excellent electrochemical performance and cycling stability, a test of 12000 cycles is carried out under the current density of 10Ag <-1 >, and the capacity retention rate after the cycles is close to 90%.

Description

Technical Field

[0001] The invention belongs to the technical field of positive electrode materials for aqueous zinc ion batteries, and in particular relates to a potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies, and a preparation method and application thereof. Background Art

[0002] The extensive application of secondary batteries has improved the quality of human life. Among them, lithium-ion batteries have dominated the battery market due to their excellent structural stability and good rate performance. However, lithium-ion batteries still have cost and safety issues, mainly due to the lack of lithium resources and thermal runaway caused by the reactivity of electrodes with flammable organic electrolytes.

[0003] Aqueous zinc-ion batteries are non-flammable, can be produced in air, are low-cost and environmentally friendly, and can replace lithium-ion batteries. Vanadium-based materials have the advantages of rich valence states, layered channels for zinc ion migration and more zinc storage sites, and have become a more promising cathode material for aqueous zinc-ion batteries.

[0004] However, vanadium-based materials still have some problems, including poor conductivity, unstable structure and slow zinc ion diffusion kinetics, which will seriously affect the electrochemical performance of the battery. In this regard, metal doping of V2O5 is an effective way to improve the electrochemical performance of zinc ion batteries. Metal doping may cause the introduction of oxygen vacancies in V2O5, reducing the Zn 2+ The interaction with vanadium oxide can also produce more zinc storage active sites, which is beneficial to improving the battery's cycle performance and capacitance contribution.

[0005] Although oxygen vacancies have a positive impact on the performance of aqueous zinc-ion batteries, their stability is an issue that needs to be addressed. During battery cycling, oxygen vacancies may reconstruct or disappear, leading to structural changes in battery materials, decreased battery performance, and reduced cycle life. Summary of the invention

[0006] In order to solve the problem that oxygen vacancies introduced into V2O5, a positive electrode material of an aqueous zinc ion battery, are unstable during the battery cycle, the present invention provides a potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies, and a preparation method and application thereof.

[0007] The technical solution of the present invention:

[0008] A positive electrode material for a potassium vanadate zinc ion battery rich in oxygen vacancies, wherein the positive electrode material is potassium ion-doped hydrated vanadium pentoxide, and the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K x V2O5·nH2O, wherein X is 0.001 to 0.5, and n is 0.3 to 1.0.

[0009] Furthermore, the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K 0.39 V2O5·0.52H2O.

[0010] A method for preparing an oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material comprises the following steps: dissolving a vanadium source in deionized water, stirring until the solution turns yellow, adding a hydrogen peroxide solution, and stirring until the solution turns orange; adding a potassium salt to the obtained orange solution, and continuously stirring to obtain a precursor solution; subjecting the obtained precursor solution to a hydrothermal reaction, and cooling, centrifugally cleaning, drying, and grinding after the reaction to obtain a positive electrode material.

[0011] Furthermore, the vanadium source is vanadium pentoxide or ammonium metavanadate, the mass concentration of the hydrogen peroxide solution is 30%, and the volume ratio of the deionized water to the hydrogen peroxide solution is 70 ml:1-20 ml.

[0012] Furthermore, the potassium salt is potassium chloride or potassium nitrate; the molar ratio of the vanadium source to the potassium salt is 1:0.001-3; and the stirring time of the precursor solution obtained by continuous stirring is 2 hours.

[0013] Furthermore, the molar ratio of the vanadium source to the potassium salt is 1:2.

[0014] Furthermore, the temperature of the hydrothermal reaction is 160-200° C., and the reaction time is 12-36 hours; and the drying is performed at 80° C. for 6 hours.

[0015] Furthermore, the temperature of the hydrothermal reaction is 180° C. and the reaction time is 24 h.

[0016] Application of an oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material in the preparation of zinc ion batteries.

[0017] Furthermore, the preparation method of the zinc ion battery is as follows: the positive electrode material of the potassium vanadate zinc ion battery rich in oxygen vacancies provided by the present invention, a conductive material, a binder and a solvent are mixed and ground, and then coated on a metal current collector, and dried to obtain a positive electrode sheet, and the negative electrode shell, the negative electrode sheet, the diaphragm, the electrolyte, the positive electrode sheet, the gasket, the spring and the positive electrode shell are packaged in the air in the order to obtain a zinc ion battery.

[0018] Furthermore, the mass ratio of the positive electrode material, the conductive material and the binder is 7:2:1, the conductive material is conductive carbon black or acetylene black, the binder is polyvinylidene fluoride, the solvent is N-methylpyrrolidone, the metal current collector is a 300-mesh stainless steel mesh or a titanium mesh, the drying temperature is 70°C for 4 to 6 hours, and the loading amount of the active material of the positive electrode sheet is 0.8-1.5 mg / cm 2 .

[0019] Furthermore, the negative electrode plate is a high-purity zinc foil with a thickness of 0.02 to 0.05 mm, the diaphragm is a medium-speed qualitative filter paper, the electrolyte is one of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride or zinc perchlorate, the concentration of the electrolyte is 1-6M, and the negative electrode shell and the positive electrode shell are CR2025 steel shell or CR2032 steel shell.

[0020] Furthermore, the thickness of the high-purity zinc foil is 0.03 mm, and the concentration of the electrolyte is 3M.

[0021] Beneficial effects of the present invention:

[0022] The present invention uses potassium ions as doping elements and obtains a potassium vanadate zinc ion battery positive electrode material with high stability and rich oxygen vacancies by precisely controlling the doping concentration and preparation process parameters. The present invention introduces oxygen-rich vacancies, which increases the difficulty of oxygen atom migration and can effectively prevent the reconstruction or disappearance of oxygen vacancies during the cycle; at the same time, oxygen-rich vacancies reduce the Zn 2+ The interaction with vanadium oxides produces more zinc storage active sites, which improves the electrochemical performance of the positive electrode material. The interlayer spacing of vanadium pentoxide is enlarged by doping with potassium ions. The pre-embedding of potassium ions can maintain the stability of the interlayer structure, avoid the structural collapse caused by the embedding of zinc ions, and improve the cycle performance of the positive electrode material. The charge density of monovalent cations is low, and doping with K + Make it with Zn 2+ The interaction between them is weakened, thus accelerating the Zn 2+ Diffusion between layers and the embedding of crystal water reduce the Zn 2+ The electrostatic repulsion with vanadium pentoxide further improves the diffusion kinetics of zinc ions.

[0023] The oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material prepared by the present invention is applied to aqueous zinc ion batteries, showing high energy density, power density, excellent electrochemical performance and cycle stability. After co-modification by doping and defect engineering, the capacity of the electrode material can reach 525mAh g at a low current density. -1 ; in 1Ag -1 Its specific capacity reaches 403 mAh g -1 ; at 10Ag -1 The test was carried out for 12,000 cycles at a current density of 1.5 %. The capacity retention rate after the cycle was close to 90%. When 3M zinc sulfate was used as the electrolyte, the capacity retention rate after the cycle was close to 90%. -1 Under the test conditions, the capacity can reach 342mAh g -1 , the capacity retention rate is 98% after 200 cycles.

[0024] The oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material of the present invention and the aqueous zinc ion battery using the material have simple preparation process, low cost, environmental friendliness and high safety, are suitable for large-scale production, and are helpful to promote the widespread application and development of aqueous zinc ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 XRD pattern of KVO-2 prepared in Example 1;

[0026] Figure 2 This is a scanning electron microscope image of KVO-2 prepared in Example 1;

[0027] Figure 3 Elemental analysis diagram of KVO-2 prepared in Example 1;

[0028] Figure 4 This is a transmission electron microscope image of KVO-2 prepared in Example 1;

[0029] Figure 5 EPR graphs of KVO-2 and VO prepared in Example 1 and Comparative Example 1;

[0030] Figure 6 The zinc ion battery assembled with the positive electrode materials prepared in Examples 1 to 3 and Comparative Example 1 and 3M Zn(CF3SO3)2 as the electrolyte was charged at 1Ag -1 Lower long cycle curve;

[0031] Figure 7 The zinc ion battery assembled with the positive electrode materials prepared in Examples 1 to 3 and Comparative Example 1 and 3M Zn(CF3SO3)2 as the electrolyte was charged at 10Ag -1 Lower long cycle curve;

[0032] Figure 8 The zinc ion battery assembled with the positive electrode material prepared in Comparative Example 2 and 3M ZnSO4 as the electrolyte was -1 Lower long cycle curve;

[0033] Fig. 9 The zinc ion battery assembled with the positive electrode material prepared in Comparative Example 2 and 3M ZnSO4 as the electrolyte was -1 The lower long cycle curve. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0035] Example 1

[0036] This embodiment provides an oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material and a preparation method thereof.

[0037] In this embodiment, the positive electrode material is potassium ion-doped hydrated vanadium pentoxide, and the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K 0.39 V2O5·0.52H2O, named KVO-2.

[0038] The preparation method of the positive electrode material in this embodiment is as follows:

[0039] Dissolve 2mmol V2O5 in 70mL deionized water, stir for 20-30 minutes until mixed into a yellow solution, then drop 10mL of 30% hydrogen peroxide solution, and continue stirring until the solution turns orange; add 4mmol potassium chloride powder to the resulting orange solution and mix evenly, stir continuously for 2h, transfer the resulting suspension to a hydrothermal reactor (80mL), and place it at 180°C for 24 hours. Take out the hydrothermal reaction system and cool it to room temperature, centrifuge and wash it three times with deionized water and anhydrous ethanol, collect the centrifugal precipitate and place it in a drying oven at 80°C for 6 hours, and grind it to obtain a powder as the positive electrode material.

[0040] This embodiment also provides a zinc ion battery and a preparation method thereof.

[0041] In this embodiment, a zinc ion battery is prepared using the prepared KVO-2 as the positive electrode material, and the specific preparation method is as follows:

[0042] (1) According to the mass ratio of positive electrode material, conductive material and binder of 7:2:1, the positive electrode material KVO-2 prepared in this example and the conductive material acetylene black were mixed evenly, and then the binder polyvinylidene fluoride was added, and an appropriate amount of N-methylpyrrolidone was dropped as a solvent. The mixture was fully ground until a uniform slurry was obtained, and the obtained slurry was evenly coated on a 300-mesh stainless steel mesh by a scraper method. The loading of the active material was controlled to be 0.8-1.2 mg cm -2 , and then transferred it to a constant temperature vacuum drying oven at 80°C overnight and taken out to obtain the positive electrode sheet.

[0043] (2) Using a cutting machine in air, high-purity zinc foil with a thickness of 0.03 mm was cut into circular sheets with a diameter of 10 mm to be used as negative electrode sheets of batteries.

[0044] (3) Using medium-speed qualitative filter paper as a separator and a 3M Zn(CF3SO3)2 aqueous solution as an electrolyte, CR2032 button-type zinc-ion batteries were assembled in an air environment using a battery packaging machine in the order of negative electrode shell, negative electrode plate, separator, electrolyte, positive electrode plate, gasket, spring and positive electrode shell.

[0045] Example 2

[0046] This embodiment provides an oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material and a preparation method thereof.

[0047] In this embodiment, the positive electrode material is potassium ion-doped hydrated vanadium pentoxide, and the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K 0.29 V2O5·0.46H2O, named KVO-1.

[0048] The preparation method of the positive electrode material in this embodiment is as follows:

[0049] Dissolve 2mmol V2O5 in 70mL deionized water, stir for 20-30 minutes until mixed into a yellow solution, then drop 10mL of 30% hydrogen peroxide solution, and continue stirring until the solution turns orange; add 2mmol potassium chloride powder to the resulting orange solution and mix evenly, stir continuously for 2h, transfer the resulting suspension to a hydrothermal reactor (80mL), and place it at 180°C for 24 hours. Take out the hydrothermal reaction system and cool it to room temperature, centrifuge and wash it three times with deionized water and anhydrous ethanol, collect the centrifugal precipitate and place it in a drying oven at 80°C for 6 hours, and grind it to obtain a powder as the positive electrode material.

[0050] This embodiment also provides a zinc ion battery and a preparation method thereof.

[0051] In this example, a zinc ion battery was prepared using the prepared KVO-1 as the positive electrode material, and the specific preparation method was the same as that in Example 1.

[0052] Example 3

[0053] This embodiment provides an oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material and a preparation method thereof.

[0054] In this embodiment, the positive electrode material is potassium ion-doped hydrated vanadium pentoxide, and the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K 0.31 V2O5·0.38H2O, named KVO-3.

[0055] The preparation method of the positive electrode material in this embodiment is as follows:

[0056] Dissolve 2mmol V2O5 in 70mL deionized water, stir for 20-30 minutes until mixed into a yellow solution, then drop 10mL of 30% hydrogen peroxide solution, and continue stirring until the solution turns orange; add 6mmol potassium chloride powder to the obtained orange solution and mix evenly, stir continuously for 2h, transfer the obtained suspension to a hydrothermal reactor (80mL), and place it at 180℃ for 24 hours. Take out the hydrothermal reaction system and cool it to room temperature, centrifuge and wash it three times with deionized water and anhydrous ethanol, collect the centrifugal precipitate and place it in a drying oven at 80℃ for 6 hours, and grind it to obtain a powder as the positive electrode material.

[0057] This embodiment also provides a zinc ion battery and a preparation method thereof.

[0058] In this embodiment, a zinc ion battery is prepared using the prepared KVO-3 as the positive electrode material, and the specific preparation method is the same as that in Example 1.

[0059] Comparative Example 1

[0060] This comparative example provides a zinc ion battery positive electrode material and a preparation method thereof.

[0061] In this comparative example, the positive electrode material is hydrated vanadium pentoxide, and the chemical composition of the hydrated vanadium pentoxide is V2O5·0.4H2O, named VO.

[0062] The preparation method of the positive electrode material in this comparative example is as follows:

[0063] Dissolve 2mmol V2O5 in 70mL deionized water, stir for 20-30 minutes until a yellow solution is mixed, then add 10mL of 30% hydrogen peroxide solution, and continue stirring until the solution turns orange; transfer the resulting orange solution to a hydrothermal reactor (80mL) and place it at 180°C for 24 hours. Take out the hydrothermal reaction system and cool it to room temperature, wash it three times with deionized water and anhydrous ethanol by centrifugation, collect the centrifugal precipitate and place it in a drying oven at 80°C for 6 hours, and grind it to obtain a powder, which is the positive electrode material.

[0064] This comparative example also provides a zinc ion battery and a preparation method thereof.

[0065] In this comparative example, a zinc ion battery was prepared using the prepared VO as the positive electrode material, and the specific preparation method was the same as that in Example 1.

[0066] Comparative Example 2

[0067] The only difference between this comparative example and Example 1 is that the electrolyte used in preparing the zinc ion battery with the prepared KVO-2 as the positive electrode material in this comparative example is a 3M ZnSO4 aqueous solution, and the other materials and preparation methods are the same as those in Example 1.

[0068] The oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material prepared in Example 1 was characterized and analyzed. Figure 1 This is the XRD pattern of KVO-2 prepared in Example 1. It was observed that KVO-2 and (Na,Ca)(V,Fe)8O 20 nH2O is consistent with the corresponding standard card JCPDS#45-1263.

[0069] Figure 2 This is a scanning electron microscope image of KVO-2 prepared in Example 1. It is observed that the prepared KVO-2 is a porous nanoflower structure, and the rich pore structure is conducive to the embedding and extraction of zinc ions.

[0070] Figure 3 This is the elemental analysis diagram of KVO-2 prepared in Example 1; K signals can be observed in the figure, proving that the doping is successful.

[0071] Figure 4 This is a transmission electron microscope image of KVO-2 prepared in Example 1; obvious lattice fringes can be observed in the image.

[0072] Figure 5 EPR graphs of KVO-2 and VO prepared in Example 1 and Comparative Example 1; wherein g=2.008, proving the existence of oxygen vacancies in KVO-2.

[0073] Table 1 shows the element content and crystal water content of the positive electrode materials prepared in Examples 1, 2, 3 and Comparative Example 1.

[0074] Table 1

[0075] serial number sample Potassium (mmol / L) Vanadium(mmol / L) K / V Crystal water content Chemical formula Example 1 KVO-2 21.9 113.1 0.39 / 2 4.49％ <h2 style=";text-align:left;direction:ltr"><![CDATA[K <h2 style=";text-align:left;direction:ltr"> 0.39 <h2 style=";text-align:left;direction:ltr"> V2O5·0.52H2O]]><h2 style=";text-align:left;direction:ltr"> Example 2 KVO-1 8.9 61.1 0.29 / 2 3.4％ <![CDATA[K 0.29 V2O5·0.46H2O]]> Example 3 KVO-3 9.3 59.1 0.31 / 2 4.1％ <h2 style=";text-align:left;direction:ltr"><![CDATA[K <h2 style=";text-align:left;direction:ltr"> 0.31 <h2 style=";text-align:left;direction:ltr"> V2O5·0.38H2O]]><h2 style=";text-align:left;direction:ltr"> Comparative Example 1 VO - - - 3.8％ <![CDATA[V2O5·0.4H2O]]>

[0076] The aqueous zinc ion batteries prepared in the embodiments and comparative examples were subjected to performance tests.

[0077] Figure 6 The zinc ion battery assembled with the positive electrode materials prepared in Examples 1 to 3 and Comparative Example 1 and 3M Zn(CF3SO3)2 as the electrolyte was charged at 1Ag -1 The long cycle curves of KVO-1, KVO-2, KVO-3 and VO electrodes are 305 mAh g -1 , 403mAh g -1 , 342mAh g -1 and 228mAh g -1. KVO-2 has the highest charge and discharge capacity and excellent electrochemical reversibility.

[0078] Figure 7 The zinc ion battery assembled with the positive electrode materials prepared in Examples 1 to 3 and Comparative Example 1 and 3M Zn(CF3SO3)2 as the electrolyte was charged at 10Ag -1 The initial capacity of the KVO-2 electrode is 258 mAh g -1 After 1000 cycles, the capacity increases to 307 mAh g -1 After 12,000 cycles, the capacity retention rate was close to 90%, while the capacity of the other three electrodes was significantly lower than that of KVO-2, and the cycle stopped halfway. This shows that the KVO-2 electrode has a high capacity retention rate under Zn 2+ The ultrafast intercalation process has good cycling performance, and the detailed results are shown in Table 2.

[0079] Table 2

[0080] serial number <![CDATA[Capacity (mAh g -1 ) / Current density (A g -1 )]]> Capacity retention rate (%) / cycles Example 1 403 / 1 92％ / 200 Example 2 305 / 1 89％ / 200 Example 3 342 / 1 98％ / 200 Comparative Example 1 228 / 1 99％ / 200 Example 1 258 / 10 91％ / 12000 Example 2 180 / 10 99％ / 7487 Example 3 240 / 10 78％ / 3712 Comparative Example 1 134 / 10 73％ / 10000

[0081] Figure 8 The zinc ion battery assembled with the positive electrode material prepared in Comparative Example 2 and 3M ZnSO4 as the electrolyte was -1 The capacity of KVO-2 electrode is 342 mAh g -1 , the capacity retention rate is 98% after 200 cycles.

[0082] Fig. 9 The zinc ion battery assembled with the positive electrode material prepared in Comparative Example 2 and 3M ZnSO4 as the electrolyte was -1 The initial capacity of the KVO-2 electrode is 184 mAh g -1 , the capacity retention rate is close to 100% after 2400 cycles.

[0083] The high performance and excellent charge / discharge capabilities demonstrate that the KVO-2 electrode has a very high adaptability, and it can exhibit excellent cycling performance and structural stability whether in zinc trifluoromethanesulfonate or zinc sulfate electrolyte.

[0084] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not used to limit the present invention. A technician in the technical field to which the present invention belongs can also make several simple deductions, deformations, substitutions or combinations based on the concept of the present invention. These deductions, deformations, substitutions or combinations also fall within the scope of the claims of the present invention.

Claims

1. A potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies, characterized in that: The positive electrode material is potassium ion-doped hydrated vanadium pentoxide, and the chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K x V2O5·nH2O, wherein X is 0.001 to 0.5, and n is 0.3 to 1.

0.

2. The potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies according to claim 1, characterized in that: The chemical composition of the potassium ion-doped hydrated vanadium pentoxide is K 0.39 V2O5·0.52H2O.

3. A method for preparing the oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material according to claim 1 or 2, characterized in that: The vanadium source is dissolved in deionized water, stirred until the solution turns yellow, and a hydrogen peroxide solution is added, and stirred until the solution turns orange; potassium salt is added to the obtained orange solution, and stirring is continued to obtain a precursor solution; the obtained precursor solution is subjected to a hydrothermal reaction, and after the reaction, the solution is cooled, centrifugally cleaned, dried, and ground to obtain a positive electrode material.

4. The method for preparing a positive electrode material of a potassium zinc vanadate battery rich in oxygen vacancies according to claim 3, characterized in that: The vanadium source is vanadium pentoxide or ammonium metavanadate, the mass concentration of the hydrogen peroxide solution is 30%, and the volume ratio of the deionized water to the hydrogen peroxide solution is 70ml:1-20ml.

5. The method for preparing a positive electrode material of a potassium zinc vanadate battery rich in oxygen vacancies according to claim 3 or 4, characterized in that: The potassium salt is potassium chloride or potassium nitrate; the molar ratio of the vanadium source to the potassium salt is 1:0.001-3; and the stirring time of the precursor solution obtained by continuous stirring is 2 hours.

6. The method for preparing a positive electrode material of a potassium zinc vanadate battery rich in oxygen vacancies according to claim 5, characterized in that: The temperature of the hydrothermal reaction is 160-200° C., and the reaction time is 12-36 hours; the drying is performed at 80° C. for 6 hours.

7. Use of the oxygen vacancy-rich potassium vanadate zinc ion battery positive electrode material as claimed in claim 1 or 2 in the preparation of a zinc ion battery.

8. The use of a potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies according to claim 7 in the preparation of a zinc ion battery, characterized in that: The preparation method of the zinc ion battery is as follows: the positive electrode material of the potassium vanadate zinc ion battery rich in oxygen vacancies described in claim 1 or 2, a conductive material, a binder and a solvent are mixed and ground, and then coated on a metal current collector, and dried to obtain a positive electrode sheet, and the negative electrode shell, the negative electrode sheet, the separator, the electrolyte, the positive electrode sheet, the gasket, the spring and the positive electrode shell are packaged in the air in the order of completing packaging to obtain a zinc ion battery.

9. According to claim 8, the use of a potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies in the preparation of a zinc ion battery, characterized in that: The mass ratio of the positive electrode material, the conductive material and the binder is 7:2:1, the conductive material is conductive carbon black or acetylene black, the binder is polyvinylidene fluoride, the solvent is N-methylpyrrolidone, the metal current collector is a 300-mesh stainless steel mesh or a titanium mesh, the drying temperature is 70°C and dried for 4 to 6 hours, and the loading amount of the active material of the positive electrode plate is 0.8-1.5 mg / cm 2 .

10. The use of a potassium vanadate zinc ion battery positive electrode material rich in oxygen vacancies according to claim 8 in the preparation of a zinc ion battery, characterized in that: The negative electrode plate is a high-purity zinc foil with a thickness of 0.02 to 0.05 mm, the diaphragm is a medium-speed qualitative filter paper, the electrolyte is one of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride or zinc perchlorate, the concentration of the electrolyte is 1-6M, and the negative electrode shell and the positive electrode shell are CR2025 steel shell or CR2032 steel shell.

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