V2O5 / ZnCo2O4 composite positive electrode material and preparation method and application thereof
Through the preparation of V2O5/ZnCo2O4 composite positive electrode material, microwave hydrothermal synthesis and spray drying technology, the problem of insufficient structural stability of the positive electrode material and zinc ion diffusion performance in aqueous zinc ion batteries was solved, and the battery performance with high specific capacity and good cycle stability was achieved.
Patent Information
- Application Number
- CN202510136352.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2025-05-06
AI Technical Summary
The development of aqueous zinc ion batteries is limited by the structural stability and zinc ion diffusion properties of the positive electrode materials. The existing V2O5 materials have low diffusion coefficient and conductivity of zinc ions during charging and discharging, and are prone to structural collapse due to vanadium dissolution.
V2O5/ZnCo2O4 composite cathode material is prepared by microwave hydrothermal synthesis and spray drying technology to form nanomaterials with good dispersion and uniform composite, and the structural stability of the material is improved by high-temperature calcination.
The high specific capacity and good cycle stability of V2O5/ZnCo2O4 composite cathode material in aqueous zinc ion batteries were achieved, and the structural collapse and low conductivity problems of the material during charging and discharging were overcome, and the diffusion rate of zinc ions and the rate performance of the battery were improved.
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Figure CN119929877A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of aqueous zinc ion batteries, and in particular to a V2O5 / ZnCo2O4 composite positive electrode material and a preparation method and application thereof. Background Art
[0002] With the increasing demand for energy and concerns about global warming in modern society, advanced new energy storage technologies have attracted widespread attention, and lithium-ion batteries are now involved in all aspects of our lives. However, limited lithium resources and a series of problems brought about by organic electrolytes, such as toxicity, safety hazards and cost issues, have seriously inhibited the future development of lithium-ion batteries. Compared with organic electrolytes, aqueous electrolytes have the advantages of high ionic conductivity, high safety, low cost and easy packaging. Among various aqueous battery systems, aqueous zinc-ion batteries have attracted widespread research interest due to their low redox potential, high theoretical capacity, easy large-scale production and environmental friendliness. However, aqueous zinc-ion batteries are largely limited by the positive electrode material. Therefore, it is necessary to find a structurally stable and Zn-ion-conserving electrolyte. 2+ Diffused positive electrode materials are of great significance to the development of aqueous zinc-ion batteries.
[0003] At present, the research on aqueous zinc ion positive electrode materials mainly focuses on vanadium-based materials, manganese-based materials, Prussian blue analogs, organic materials and transition metal sulfides. my country has rich vanadium ore resources, and vanadium has multiple valence states and rich chemical structure characteristics, which is conducive to the preparation of vanadium-based materials with high energy storage capacity, becoming an aqueous zinc ion positive electrode material with great application potential. Among them, V2O5 with a layered structure can accommodate a large amount of Zn due to its open framework structure. 2+ However, the use of V2O5 materials is limited by the low diffusion coefficient and conductivity of zinc ions and the dissolution of vanadium during the charge and discharge process. Summary of the invention
[0004] In view of this, the present application provides a V2O5 / ZnCo2O4 composite positive electrode material and a preparation method and application thereof. The preparation method is simple to synthesize and has low cost. The prepared V2O5 / ZnCo2O4 composite positive electrode material has high specific capacity and good cycle stability when used in aqueous zinc ion batteries, and can effectively overcome the structural collapse caused by vanadium dissolution during the charge and discharge process, the low conductivity of the material itself and the poor Zn 2+ Diffusion rate defects.
[0005] The first aspect of the present application provides a method for preparing a V2O5 / ZnCo2O4 composite positive electrode material, comprising the following steps:
[0006] S1, dissolving a vanadium source, a zinc source, a cobalt source and a surfactant in a solvent, and stirring them evenly with a magnetic force to obtain a mixed solution;
[0007] S2, subjecting the mixed solution to microwave heating reaction, and obtaining an intermediate substance after washing;
[0008] S3, adding the intermediate material into a solvent and performing magnetic stirring, and spray drying to obtain a secondary granulated intermediate powder material;
[0009] S4. calcining the powder material to obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0010] Specifically, the preparation method of the V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0011] S1. Dissolve the vanadium source, zinc source, cobalt source and surfactant in a solvent, and stir them evenly with a magnetic stirrer in a beaker to obtain a mixed solution;
[0012] S2, transferring the mixed solution to a reactor, heating it with a microwave, and after sufficient reaction, washing it with a cleaning agent to obtain an intermediate substance;
[0013] S3, transferring the intermediate material into a beaker for magnetic stirring, and spray drying to obtain a secondary granulated intermediate powder material;
[0014] S4. Put the powder material into a crucible and place it in a muffle furnace for high-temperature calcination to obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0015] It should be noted that the Zn formed in the ZnCo2O4 structure 2+ Vacancies can provide more reaction sites; ZnCo2O4 usually presents a spinel structure, which is conducive to the migration of ions and electrons. The metal ions in the spinel structure can move between different lattice positions, thereby improving conductivity; the material itself has high crystallinity and excellent electrochemical properties, and can maintain good structural stability in aqueous electrolytes. Therefore, it is particularly important to solve the structural collapse of V2O5 materials during charging and discharging, improve structural stability, increase conductivity, and optimize electrochemical performance through modification strategies such as composite or doping.
[0016] Preferably, in step S2, the specific process of the microwave heating reaction is: transferring the mixed solution to a reaction kettle, wherein the volume of the reaction kettle is 50 ml, 75 ml or 100 ml, the microwave heating temperature is 100-200° C., and the microwave heating time is 4-12 h.
[0017] Preferably, in step S3, the speed of the magnetic stirring is 100-2000 rpm, and the stirring time is 0.5-12 h; or
[0018] In step S3, the feed rate of the spray drying is 1-20 L / h, the air inlet temperature is 200-300° C., and the outlet temperature is 80-140° C.; or
[0019] In step S3, the solvent is at least one of deionized water, acetone, and ethanol, and the intermediate substance is added to the solvent at a concentration of 10-70 wt %.
[0020] Preferably, in step S4, the specific process of calcination is: putting the powder material into a crucible and placing it in a muffle furnace, calcining it in an air, nitrogen or argon atmosphere, the calcination temperature is 300-800° C., and the calcination time is 1-24 hours.
[0021] Preferably, in step S1, the rotation speed of the magnetic stirring is 100-2000 rpm, and the stirring time is 0.5-12 h.
[0022] Preferably, in step S1, the mass ratio of the vanadium source to the surfactant is 1:(0.01-0.1); the molar ratio of the vanadium in the vanadium source to the zinc in the zinc source is 1:(0.01-1.0); the molar ratio of the zinc in the zinc source to the cobalt in the cobalt source is 1:(1.8-2.2); and the concentration of the vanadium source in the mixed solution is 0.01-5.0 mol / L.
[0023] Preferably, in step S1, the vanadium source is selected from at least one of vanadium pentoxide, ammonium metavanadate, and vanadium chloride; the zinc source is selected from at least one of zinc acetate, zinc nitrate, zinc sulfate, and zinc chloride; the cobalt source is selected from at least one of cobalt acetate, cobalt nitrate, cobalt sulfate, and cobalt chloride; the surfactant is selected from at least one of polyethylene glycol 200-20000, polyvinyl pyrrolidone, sodium dodecyl sulfate, and hexadecyltrimethylammonium chloride; and the solvent is selected from at least one of deionized water, ethanol, and ethylene glycol.
[0024] The second aspect of the present application also provides a V2O5 / ZnCo2O4 composite positive electrode material, which is a V2O5 / ZnCo2O4 composite positive electrode material prepared by the above method.
[0025] The third aspect of the present application also provides the use of the above-mentioned V2O5 / ZnCo2O4 composite positive electrode material in aqueous zinc ion batteries.
[0026] The fourth aspect of the present application also provides an aqueous zinc ion battery, comprising a battery housing, an electrode group and an electrolyte, wherein the electrode group and the electrolyte are sealed in the battery housing, the electrode group comprises a positive electrode, a diaphragm and a negative electrode, and the above-mentioned V2O5 / ZnCo2O4 composite positive electrode material is used as the active material of the positive electrode of the aqueous zinc ion battery.
[0027] Compared with the prior art, this application has the following beneficial effects:
[0028] 1. The method of the present application utilizes microwave hydrothermal synthesis to raise the reaction temperature in a short time, so that all components in the reaction system are heated evenly, reducing the temperature gradient, which is conducive to the preparation of nanomaterials with uniform particle size; the intermediate substance is efficiently synthesized at nanometer size under low temperature conditions, and the purity of the intermediate substance of the composite material and the uniformity of the composite are improved; at the same time, spray drying is used to effectively prepare intermediate substances with good dispersibility and uniform size; finally, after high-temperature calcination, a composite material with uniformity, stable structure and regular morphology is obtained.
[0029] 2. The preparation method provided by the present application can keep the material uniformly dispersed from the preparation process of the intermediate, and can achieve uniform compounding and good crystallization of V2O5 and ZnCo2O4; when it is used as the positive electrode material of aqueous zinc ion battery, the structure is well maintained during the charge and discharge process, and the cycle stability and rate performance of the material are improved by ZnCo2O4 composite technology; this is attributed to the good ionic conductivity of zinc cobalt oxide itself, and the Zn produced by ZnCo2O4 2+ The vacancies provide additional active sites for the V2O5 / ZnCo2O4 composite material during the charge and discharge process, thereby improving the energy density and charge and discharge efficiency of the V2O5 material. At the same time, ZnCo2O4 has strong structural stability in an aqueous environment. For the structural collapse of the V2O5 material caused by the volume change due to the insertion and extraction of zinc ions, an appropriate amount of compounding alleviates the volume change of the V2O5 material, which helps V2O5 maintain the stability of the crystal structure when zinc ions are repeatedly inserted and extracted, so that the battery has better cycle stability during the charge and discharge process. The method of the present application is simple to operate, has low raw material cost, and can achieve the purpose of low-cost continuous production. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the description of the present application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0031] Figure 1XRD diagrams of the V2O5 / ZnCo2O4 composite positive electrode material prepared in Example 1 and the V2O5 material prepared in Comparative Example 1;
[0032] Figure 2 This is a SEM image of the V2O5 / ZnCo2O4 composite positive electrode material prepared in Example 1;
[0033] Figure 3 The rate cycling performance diagrams of Example 1, Comparative Example 1 and Example 7 at different current densities;
[0034] Figure 4 These are the cycle stability performance diagrams of Example 1, Comparative Example 1, and Example 7. DETAILED DESCRIPTION
[0035] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0036] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.
[0037] In the following examples and comparative examples, unless otherwise specified, all raw materials can be purchased commercially or prepared by conventional methods. Polyethylene glycol 400-20000 refers to a type of polyethylene glycol, which is divided into polyethylene glycol 400-20000 according to the difference in average molecular weight.
[0038] Example 1
[0039] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0040] (1) 1.81 g of vanadium pentoxide, 0.284 g of zinc nitrate, 0.861 g of cobalt nitrate, and 0.09 g of polyethylene glycol 2000 were accurately weighed and added in sequence to 50 ml of a mixed solution of deionized water and ethylene glycol in a volume ratio of 4:1. The mixture was magnetically stirred at 600 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0041] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 160° C. for continuous reaction for 6 hours. After the reaction was completed, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0042] (3) 5 g of the intermediate material was transferred to a beaker and 20 ml of deionized water was added, and magnetic stirring was performed at a speed of 500 rpm for 30 min. After the stirring was completed, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 240 ° C, the outlet temperature was 100 ° C, and the feed rate was 1 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and calcined continuously at 400 ° C for 2 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0043] Figure 1 The XRD diagram of the X-ray diffraction test of the V2O5 / ZnCo2O4 composite positive electrode material prepared in Example 1 and the V2O5 material prepared in Comparative Example 1 shows the characteristic peaks of vanadium pentoxide in Example 1, which correspond to the standard PDF card 42-1426. At the same time, most of the characteristic peaks of ZnCo2O4 are also shown in Example 1, which correspond to the standard PDF card 23-1390, and no new diffraction peaks appear. This proves that the composite of V2O5 and ZnCo2O4 is successfully achieved.
[0044] Figure 2 This is the SEM image of the V2O5 / ZnCo2O4 composite positive electrode material prepared in Example 1, showing that it is composed of micron-sized microspheres composed of smaller lamellar structures. The lamellar structure is because the presence of ZnCo2O4 affects the original growth orientation of V2O5. At the same time, due to the addition of surfactants, the lamellar structure continues to aggregate into micron-sized microspheres. This unique structure provides a larger specific surface area and more active sites, resulting in better specific capacity and stronger structural stability during the charge and discharge process.
[0045] Example 2
[0046] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0047] (1) Accurately weigh 1.81 g of vanadium pentoxide, 0.095 g of zinc sulfate, 0.164 g of cobalt sulfate, and 0.108 g of polyvinyl pyrrolidone, and add them to 50 ml of deionized water in sequence. Stir magnetically at 500 rpm for 0.5 h to fully dissolve the solutes therein to obtain a uniform mixed solution.
[0048] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 120° C. for continuous reaction for 10 h. After the reaction, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0049] (3) 4 g of the intermediate material was transferred to a beaker and added to 30 ml of ethanol, and magnetically stirred at 500 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 220 ° C, the outlet temperature was 90 ° C, and the feed rate was 1 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and continuously calcined at 350 ° C for 3 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0050] Example 3
[0051] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0052] (1) 2.172 g of ammonium metavanadate, 0.439 g of zinc acetate, 0.687 g of cobalt acetate, and 0.152 g of sodium dodecyl sulfate were accurately weighed and added in sequence to 50 ml of a mixed solution of deionized water and ethanol in a volume ratio of 4:1, and magnetically stirred at 700 rpm for 1 h to fully dissolve the solutes therein to obtain a uniform mixed solution.
[0053] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 140° C. for continuous reaction for 8 h. After the reaction, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0054] (3) 5 g of the intermediate material was transferred to a beaker and added to 25 ml of ethanol, and magnetically stirred at 400 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 260°C, the outlet temperature was 110°C, and the feed rate was 2 L / h to obtain a powdered material. The resulting powdered material was then placed in a crucible and placed in a muffle furnace, and calcined continuously at 450°C for 2 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0055] Example 4
[0056] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0057] (1) 1.884 g of vanadium chloride, 0.413 g of zinc chloride, 0.741 g of cobalt chloride, and 0.108 g of hexadecyltrimethylammonium chloride were accurately weighed and added in sequence to 75 ml of a mixed solution of deionized water and ethanol in a volume ratio of 4:1. The mixture was stirred magnetically at 600 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0058] (2) The mixed solution was transferred to a reactor with a volume of 100 ml and placed in a microwave hydrothermal synthesizer at 160° C. for continuous reaction for 6 hours. After the reaction, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0059] (3) 6 g of the intermediate material was transferred to a beaker and added to 10 ml of deionized water and 15 ml of ethanol, and magnetically stirred at 600 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 240 ° C, the outlet temperature was 100 ° C, and the feed rate was 2 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and continuously calcined at 500 ° C for 1 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0060] Example 5
[0061] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0062] (1) Accurately weigh 2.172 g of ammonium metavanadate, 0.816 g of zinc chloride, 1.672 g of cobalt sulfate, and 0.172 g of sodium dodecyl sulfate, and add them to 75 ml of deionized water in sequence. Stir magnetically at 500 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0063] (2) The mixed solution was transferred to a reactor with a volume of 100 ml and placed in a microwave hydrothermal synthesizer at 130° C. for continuous reaction for 10 h. After the reaction, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0064] (3) 5 g of the intermediate material was transferred to a beaker and added to 20 ml of deionized water and 5 ml of acetone, and magnetically stirred at 400 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 260 ° C, the outlet temperature was 110 ° C, and the feed rate was 1.5 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and continuously calcined at 550 ° C for 2 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0065] Example 6
[0066] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0067] (1) Accurately weigh 1.81 g of vanadium pentoxide, 0.661 g of zinc nitrate, 1.223 g of cobalt nitrate, and 0.15 g of polyethylene glycol 500, and add them to 50 ml of deionized water in sequence. Stir the mixture with a magnetic stirrer at 600 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0068] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 160° C. for continuous reaction for 6 hours. After the reaction was completed, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0069] (3) The intermediate material was transferred to a beaker and an appropriate amount of deionized water was added, and magnetic stirring was performed at 600 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 240°C, the outlet temperature was 100°C, and the feed rate was 1 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and calcined continuously at 400°C for 2 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite positive electrode material.
[0070] Example 7
[0071] A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material comprises the following steps:
[0072] (1) 1.81 g of vanadium pentoxide, 0.756 g of zinc nitrate, 1.642 g of cobalt nitrate, and 0.19 g of polyethylene glycol 2000 were accurately weighed and added in sequence to 50 ml of a mixed solution of deionized water and ethylene glycol in a volume ratio of 4:1. The mixture was magnetically stirred at 600 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0073] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 160° C. for continuous reaction for 6 hours. After the reaction was completed, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0074] (3) 5 g of the intermediate material was transferred to a beaker and added to 20 ml of deionized water, and magnetically stirred at 500 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 240° C., the outlet temperature was 100° C., and the feed rate was 1 L / h to obtain a powdered material. The resulting powdered material was then placed in a crucible and placed in a muffle furnace, and calcined continuously at 400° C. for 2 h in an air atmosphere to finally obtain a V2O5 / ZnCo2O4 composite material.
[0075] Comparative Example 1
[0076] A method for preparing a V2O5 material comprises the following steps:
[0077] (1) 1.81 g of vanadium pentoxide and 0.09 g of polyethylene glycol 2000 were accurately weighed and added to 50 ml of a mixed solution of deionized water and ethylene glycol in a volume ratio of 4:1, and magnetically stirred at 600 rpm for 1 h to fully dissolve the solutes and obtain a uniform mixed solution.
[0078] (2) The mixed solution was transferred to a reactor with a volume of 75 ml and placed in a microwave hydrothermal synthesizer at 160° C. for continuous reaction for 6 hours. After the reaction was completed, the obtained product was washed by alternating centrifugation with deionized water and ethanol to obtain an intermediate substance.
[0079] (3) 5 g of the intermediate material was transferred to a beaker and added to 20 ml of deionized water, and magnetically stirred at 500 rpm for 30 min. After stirring, the resulting solution was spray dried, wherein the inlet temperature of the spray drying was 240° C., the outlet temperature was 100° C., and the feed rate was 1 L / h to obtain a powdered material. The obtained powdered material was then placed in a crucible and placed in a muffle furnace, and continuously calcined at 400° C. for 2 h in an air atmosphere to finally obtain a V2O5 material.
[0080] The V2O5 material obtained in Example 1 was subjected to an X-ray diffraction test, and the results are as follows: Figure 1 As shown, the material exhibits characteristic peaks of vanadium pentoxide, which correspond one to one with the standard PDF card 42-1426, and no new diffraction peaks appear, which proves that the V2O5 material has been successfully synthesized.
[0081] Test Case
[0082] 1. The positive electrode sheet was made of the materials prepared in Example 1, Comparative Example 1 and Example 7, wherein the positive electrode sheet had a diameter of 12 mm, a high-purity zinc foil (12 mm diameter disc) with a thickness of 20-50 microns was used as the negative electrode of the battery, the electrolyte used was a zinc trifluoromethanesulfonate solution, wherein the concentration of zinc trifluoromethanesulfonate in the electrolyte was 2.5-3.5 mol / L, and the diaphragm used was a GF / A glass fiber diaphragm with a diameter of 14 mm to better infiltrate the zinc trifluoromethanesulfonate electrolyte. The positive electrode shell, the positive electrode sheet, the diaphragm infiltrated with the electrolyte, the zinc negative electrode, the gasket, and the negative electrode shell were sequentially discharged and pressurized and packaged to assemble a 2016-type button aqueous zinc ion battery, which was then placed in a blue electricity test system to test the battery performance.
[0083] 2. The V2O5 / ZnCo2O4, V2O5, and V2O5 / ZnCo2O4 prepared in Example 1, Comparative Example 1, and Example 7 were used as positive electrode materials, and the assembled aqueous zinc ion batteries were charged and discharged at different rates. Figure 3 As shown, when the V2O5 / ZnCo2O4 composite positive electrode material prepared in Example 1 is used as an aqueous zinc ion positive electrode material, the specific capacity can reach 474mAh / g at the first discharge at 100mA / g, and can also release a specific capacity of about 320mAh / g at a large current of 5.0A / g. The V2O5 material prepared in Comparative Example 1 has a discharge specific capacity of about 204mAh / g at 100mA / g, and a discharge specific capacity of about 100mAh / g at 5.0A / g. It can be seen that the performance of Comparative Example 1 is much lower than that of Example 1 under the same test conditions. When the V2O5 / ZnCo2O4 composite material prepared in Example 7 is used as an aqueous zinc ion positive electrode material, it also reaches a specific capacity of 385mAh / g at the first discharge at 100mA / g, and can also release a specific capacity of about 268mAh / g at a large current of 5.0A / g. Although the rate performance of the composite material prepared in Example 7 is not as good as that of the composite material prepared in Example 1, it is still significantly improved compared with the uncompounded V2O5 material prepared in Comparative Example 1. Figure 3 It can be found that different compounding ratios can improve the rate performance, but a small amount or excessive compounding weakens the effect of improving performance.
[0084] Depend on Figure 4 It can be seen from the cyclic stability performance diagram of the materials obtained in Example 1, Comparative Example 1 and Example 7 as the positive electrode materials of aqueous zinc ion batteries at 5.0A / g that after 700 long cycles at a high current of 5.0A / g, the discharge specific capacity of the V2O5 / ZnCo2O4 composite material obtained in Example 1 dropped from the highest 320mAh / g to 310mAh / g, and the capacity retention rate was about 96.8%. The initial discharge specific capacity of the V2O5 material obtained in Comparative Example 1 under the same conditions was 101mAh / g, and after 700 cycles, it was 79mAh / g, and the capacity retention rate was about 78%. It can be seen that both the initial specific capacity and the final specific capacity of Example 1 are significantly higher than those of Comparative Example 1, and the cycle curve of Example 1 is smoother than that of Comparative Example 1, indicating that the material structure stability is stronger and the reaction is more repeatable during the cycle. At the same time, the discharge specific capacity of the V2O5 / ZnCo2O4 composite material prepared in Example 7 after 700 cycles is also higher than that of Comparative Example 1, which indicates that the composite of ZnCo2O4 in different proportions can also improve the electrochemical properties of the V2O5 material itself.
[0085] The present application has been optimized many times during the preparation process to prepare a composite material with uniform compounding, regular morphology and high purity. The material prepared by the method of the present application is used as the positive electrode material of an aqueous zinc-ion battery, which shows high rate performance and stable cycle performance. The synthesized material has uniform morphology and stable structure, which is attributed to the good structural stability of ZnCo2O4 in an aqueous environment. The uniform compounding inhibits the structural collapse of V2O5 caused by dissolution during the cycle; under the joint action of ZnCo2O4 and surfactants, V2O5 forms micrometer-sized microspheres composed of a lamellar structure. This structure provides a larger specific surface area and more active sites, which is beneficial to improve the discharge specific capacity; at the same time, ZnCo2O4 itself has good ionic conductivity, and the Zn formed during the cycle 2+ The vacancies further improve the ionic conductivity of the composite material, giving the battery higher capacity and better structural stability during the charge and discharge process.
[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for preparing a V2O5 / ZnCo2O4 composite positive electrode material, characterized in that: The following steps are involved: S1, dissolving a vanadium source, a zinc source, a cobalt source and a surfactant in a solvent, and stirring them evenly with a magnetic force to obtain a mixed solution; S2, subjecting the mixed solution to microwave heating reaction, and obtaining an intermediate substance after washing; S3, adding the intermediate material into a solvent and performing magnetic stirring, and spray drying to obtain a secondary granulated intermediate powder material; S4. calcining the powder material to obtain a V2O5 / ZnCo2O4 composite positive electrode material.
2. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S2, the specific process of the microwave heating reaction is: transferring the mixed solution to a reaction vessel, the microwave heating temperature is 100-200° C., and the microwave heating time is 4-12 h.
3. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S3, the rotation speed of the magnetic stirring is 100-2000 rpm, and the stirring time is 0.5-12 h; or In step S3, the feed rate of the spray drying is 1-20 L / h, the air inlet temperature is 200-300° C., and the outlet temperature is 80-140° C.; or In step S3, the solvent is at least one of deionized water, acetone, and ethanol, and the intermediate substance is added to the solvent at a concentration of 10-70 wt %.
4. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S4, the specific process of calcination is: putting the powder material into a crucible and placing it in a muffle furnace, calcining it in an air, nitrogen or argon atmosphere, the calcination temperature is 300-800° C., and the calcination time is 1-24 hours.
5. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S1, the rotation speed of the magnetic stirring is 100-2000 rpm, and the stirring time is 0.5-12 h.
6. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S1, the mass ratio of the vanadium source to the surfactant is 1:(0.01-0.1); the molar ratio of the vanadium in the vanadium source to the zinc in the zinc source is 1:(0.01-1.0); the molar ratio of the zinc in the zinc source to the cobalt in the cobalt source is 1:(1.8-2.2); and the concentration of the vanadium source in the mixed solution is 0.01-5.0 mol / L.
7. The method for preparing the V2O5 / ZnCo2O4 composite positive electrode material according to claim 1, characterized in that: In step S1, the vanadium source is selected from at least one of vanadium pentoxide, ammonium metavanadate, and vanadium chloride; the zinc source is selected from at least one of zinc acetate, zinc nitrate, zinc sulfate, and zinc chloride; the cobalt source is selected from at least one of cobalt acetate, cobalt nitrate, cobalt sulfate, and cobalt chloride; the surfactant is selected from at least one of polyethylene glycol 200-20000, polyvinyl pyrrolidone, sodium dodecyl sulfate, and hexadecyltrimethylammonium chloride; and the solvent is selected from at least one of deionized water, ethanol, and ethylene glycol.
8. A V2O5 / ZnCo2O4 composite positive electrode material, characterized in that: A V2O5 / ZnCo2O4 composite positive electrode material prepared by the method described in any one of claims 1 to 7.
9. Use of the V2O5 / ZnCo2O4 composite positive electrode material according to claim 8 in aqueous zinc ion batteries.
10. An aqueous zinc ion battery, comprising a battery housing, an electrode group and an electrolyte, wherein the electrode group and the electrolyte are sealed in the battery housing, the electrode group comprises a positive electrode, a diaphragm and a negative electrode, characterized in that: The V2O5 / ZnCo2O4 composite positive electrode material described in claim 8 is used as the active material of the positive electrode of an aqueous zinc ion battery.