Preparation method and application of aqueous zinc ion battery positive electrode material

Abstract

The invention discloses a preparation method and application of an aqueous zinc ion battery positive electrode material, and belongs to the technical field of electrochemical energy storage. The carbon-vanadium zinc oxide ion battery positive electrode material comprises a nanosheet stacked structure which is composed of carbon and V2O3 and has the length-diameter ratio of 20-60, and the preparation method comprises the following steps: mixing vanadium salt, a ligand and a regulator, and carrying out hydrothermal reaction to obtain a V-MOF precursor; and carrying out carbonization treatment on the V-MOF precursor to obtain the carbon-vanadium oxide zinc ion battery positive electrode material. According to the preparation method, the V-MOF precursor is prepared from the vanadium salt, the ligand and the regulator, the flaky V2O3 and carbon compound is obtained after carbonization, and then the electrical conductivity and the structural stability of the product are improved in a selenylation mode, so that important technical support is provided for practical application of the zinc ion battery.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy storage, and in particular to a preparation method and application of a positive electrode material for an aqueous zinc ion battery. Background Art

[0002] As global energy demand continues to grow, developing efficient and environmentally friendly energy storage systems has become crucial for achieving sustainable development. Among numerous energy storage technologies, zinc-ion batteries (ZIBs) have become a research hotspot due to their unique advantages, such as high theoretical specific capacity, low cost, environmental friendliness, and high safety. The theoretical specific capacity of ZIBs is as high as 820 mAh / g, significantly higher than the 372 mAh / g of lithium-ion batteries. Furthermore, the abundance and low price of zinc resources give ZIBs a significant cost advantage in large-scale energy storage applications.

[0003] Despite their numerous advantages, zinc-ion batteries (Zn-ion batteries) face several challenges in their development. For example, the growth of zinc dendrites and the frequent occurrence of side reactions can severely impact the battery's cycle life and safety. To address these issues, researchers have proposed a variety of strategies, including developing novel electrolytes, optimizing electrode material structures, and introducing protective layers. Regarding electrode materials, researchers are committed to developing high-performance cathode materials to improve the overall performance of Zn-ion batteries. Flake V2O3, due to its unique structure and properties, is considered a promising cathode material for Zn-ion batteries.

[0004] Vanadium trioxide (V2O3), as a typical transition metal oxide, has unique physical and chemical properties. It has a high theoretical specific capacity and good electrochemical activity, which makes it have potential application value in the field of electrochemical energy storage. The crystal structure and electronic properties of V2O3 enable it to effectively embed and extract zinc ions, thereby achieving efficient electrochemical reactions. In addition, the layered structure of V2O3 helps to increase the ion transfer rate, which is crucial for improving the rate performance of the battery. However, current V2O3-based electrode materials still have problems such as low capacity, poor rate performance, and insufficient stability, and further research and improvement are still needed. Summary of the Invention

[0005] The object of the present invention is to provide a preparation method and application of an aqueous zinc ion battery positive electrode material to solve the above-mentioned problems in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a carbon-vanadium oxide zinc ion battery positive electrode material, wherein the positive electrode material comprises a nanosheet stacking structure composed of carbon and V2O3 with an aspect ratio of 20 to 60.

[0008] The second technical solution of the present invention is to provide a method for preparing the above-mentioned carbon-vanadium oxide zinc ion battery positive electrode material, comprising the following steps:

[0009] The vanadium salt, ligand and regulator are mixed and subjected to hydrothermal reaction to obtain a V-MOF precursor;

[0010] The V-MOF precursor is carbonized to obtain the carbon-vanadium oxide zinc ion battery positive electrode material.

[0011] Preferably, the vanadium salt is ammonium metavanadate (NH4VO3).

[0012] Preferably, the ligand is terephthalic acid (PTA).

[0013] Preferably, the regulator comprises hydrochloric acid (HCl) and citric acid (CA), which are used to achieve pH regulation and chelation and sustained release of metal ions to optimize the synthesis process of the precursor.

[0014] Preferably, the mass ratio of the vanadium salt, the ligand and the regulator is 3:4:1.

[0015] Preferably, the step of mixing the vanadium salt, the ligand and the regulator comprises: dissolving NH4VO3 and PTA in anhydrous ethanol to obtain solution A; dissolving CA in deionized water to obtain solution B; adding hydrochloric acid and the solution B to solution A and mixing and stirring uniformly.

[0016] Preferably, the temperature of the hydrothermal reaction is 120° C. and the time is 24 hours.

[0017] Preferably, the carbonization treatment is carried out at a temperature of 600 to 1000° C., for a time of 2 to 8 hours, in a protective atmosphere.

[0018] The V2O3 / C composite material obtained after carbonization treatment has a nano-sheet structure.

[0019] Preferably, after the carbonization treatment, a selenization treatment step is further included, and the selenization treatment includes: mixing the composite material obtained after the carbonization treatment with a selenium source and performing selenization treatment.

[0020] More preferably, the selenium source in the selenization treatment includes selenium oxide or selenium, and the temperature of the selenization treatment is 550-850° C., and the time is 0.5-4 hours.

[0021] The present invention prepares selenium-modified V2O3 / C composite materials through a high-temperature selenization process. The addition of heteroatom selenium significantly increases the defects of carbonaceous components and improves the electrical conductivity, thereby increasing the Zn content of V2O3 / C. 2+ Storage performance.

[0022] The selenization of the present invention does not form selenides, and the main purpose is to add selenium elements into the lattice of carbon or vanadium oxide, which is equivalent to selenium doping.

[0023] Preferably, before the hydrothermal reaction, a step of adding metal doping ions is further included; including Fe, Co, Mn, Cu, Ce or Ba, etc.; the molar ratio of the metal doping ions to the vanadium salt is 1:5-20.

[0024] After actual testing, it was found that if selenization is carried out by adding a selenium source before the hydrothermal reaction, the doping effect is not good.

[0025] The third technical solution of the present invention is to provide an application of the above-mentioned carbon-vanadium oxide zinc ion battery positive electrode material in a zinc ion battery.

[0026] The fourth technical solution of the present invention is to provide a zinc ion battery, wherein the positive electrode comprises the above-mentioned carbon-vanadium oxide zinc ion battery positive electrode material.

[0027] Preferably, the electrolyte of the zinc ion battery is a 2 mol / L zinc sulfate heptahydrate (ZnSO4·7H2O) aqueous solution.

[0028] Preferably, the electrolyte is further doped with metal ions; the molar ratio of the doping amount of the metal ions to zinc sulfate heptahydrate is 1:10 to 1000; the types of the metal ions include Fe, Co, Mn or Cu.

[0029] The present invention further optimizes the charge and discharge performance of the battery by adding metal ions during the preparation process of the electrolyte.

[0030] In the present invention, the carbon-vanadium oxide zinc ion battery positive electrode material is doped and modified, and the electrolyte is doped, which can significantly improve the comprehensive performance of the zinc ion battery, including improving conductivity, increasing battery specific capacity, improving its charge and discharge rate performance, enhancing structural stability, improving ion transport performance, inhibiting dendrite growth, improving solvation structure, widening the electrochemical stability window, etc., thereby improving battery cycle stability, thereby providing important technical support for the practical application of zinc ion batteries.

[0031] The beneficial technical effects of the present invention are as follows:

[0032] The present invention uses a vanadium-based metal-organic framework (V-MOF) as a precursor to prepare a V2O3 / C composite material as a positive electrode material for a zinc ion battery. The doping process further improves the rapid charge and discharge performance and cycle stability of the zinc ion battery, which is beneficial to improving the energy density and charge and discharge performance of the zinc ion battery.

[0033] The stacked, porous nanosheet structure of carbon-vanadium oxide zinc-ion battery cathode materials facilitates rapid electrolyte inflow and outflow, mitigating volume changes during charge and discharge. Selenium modification further enhances zinc storage performance without altering the sheet structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 The SEM images of the electrode materials prepared in Example 1 and Example 2, wherein a is the V-MOF precursor in Example 1, b is the V2O3 / C in Example 1, and c is the V2O3 / C-Se in Example 2;

[0036] Figure 2 TEM images, HRTEM images, and XRD images of V2O3 / C-Se of Example 2, wherein a is a TEM image, b is a HRTEM image, and c is an XRD image;

[0037] Figure 3 The discharge capacity-cycle number curve comparison of the zinc ion battery assembled with the electrode materials of Example 1 and Example 2 at 1A / g constant current discharge, wherein a is the V2O3 / C and different Mn 2+ Performance comparison diagram of electrolyte combinations with different contents, b is the rate performance diagram of V2O3 / C-Se-Mn, c is the cycle diagram of V2O3 / C, V2O3 / C-Mn, and V2O3 / C-Se-Mn; d is the cycle diagram of V2O3 / C-Se and V2O3 / C-Se-Mn;

[0038] Figure 4 Impedance test results of zinc ion batteries assembled with the electrode materials of Examples 1 and 2;

[0039] Figure 5 1 and 2 are Raman test results of the electrode materials prepared in Example 1 and Example 2, wherein a is V2O3 / C in Example 1 and b is V2O3 / C-Se in Example 2.

[0040] Figure 6 This is a cycle diagram of a zinc ion battery assembled with the electrode materials of Example 3 and Example 4, wherein a is Example 3 and b is Example 4. DETAILED DESCRIPTION

[0041] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0042] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0043] Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. It should be noted that any details not described herein are conventional procedures in the art and are not the focus of the present invention.

[0044] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0045] Unless otherwise specified, the "room temperature" in the present invention is 10-30°C.

[0046] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0047] Example 1

[0048] A method for preparing a positive electrode material for an aqueous zinc ion battery comprises the following steps:

[0049] S1. Take 0.5839g of ammonium metavanadate (NH4VO3) and 0.83g of terephthalic acid (PTA) and dissolve them in 25mL of anhydrous ethanol to obtain solution A; take 0.194g of citric acid monohydrate (CA) and dissolve it in 25mL of deionized water to obtain solution B. Add 10mL of HCl solution (concentration of 1mol / L) and solution B to solution A respectively and stir them thoroughly. After mixing evenly, hydrothermally react at 120℃ for 24h to obtain V-MOF precursor;

[0050] S2. The V-MOF precursor is placed in a crucible and carbonized under an inert atmosphere (specifically nitrogen). The heating rate of the carbonization treatment is 5°C / min, the holding temperature is 700°C, and the holding time is 3 hours. It is then naturally cooled to room temperature to obtain an aqueous zinc ion battery positive electrode material, which is recorded as V2O3 / C.

[0051] Example 2 (Selenization Treatment)

[0052] A method for preparing a positive electrode material for an aqueous zinc ion battery comprises the following steps:

[0053] S1. Take 0.5839g of ammonium metavanadate (NH4VO3) and 0.83g of terephthalic acid (PTA) and dissolve them in 25mL of anhydrous ethanol to obtain solution A; take 0.194g of citric acid monohydrate (CA) and dissolve it in 25mL of deionized water to obtain solution B. Add 10mL of HCl solution (concentration of 1mol / L) and solution B to solution A respectively and stir them thoroughly. After mixing evenly, hydrothermally react at 120℃ for 24h to obtain V-MOF precursor;

[0054] S2. The V-MOF precursor was placed in a crucible and carbonized under an inert atmosphere at a heating rate of 5°C / min, a holding temperature of 700°C, and a holding time of 3 h. The product was then naturally cooled to room temperature to obtain a V2O3 / C composite material, which was recorded as V2O3 / C.

[0055] S3. Take 0.1g V2O3 / C and 0.5g selenium powder and place them in a crucible respectively. Heat the temperature to 600℃ at a heating rate of 5℃ / min and then perform selenization treatment for 2h. After cooling to room temperature, the zinc ion battery positive electrode material is obtained, which is recorded as V2O3 / C-Se.

[0056] Figure 1 These are SEM images of the electrode materials prepared in Example 1 and Example 2, wherein a is the V-MOF precursor in Example 1, b is the V2O3 / C in Example 1, and c is the V2O3 / C-Se in Example 2.

[0057] Depend on Figure 1 It can be seen that the V-MOF precursor is composed of interconnected nanosheet stacks, and the V2O3 / C composite material after carbonization still maintains a lamellar morphology, with no discernible structural collapse or deformation observed. After selenization, (V2O3 / C-Se) still maintains a lamellar structure, and its aspect ratio is 20-60.

[0058] Figure 2 These are the TEM images, HRTEM images and XRD images of V2O3 / C-Se of Example 2, where a is the TEM image, b is the HRTEM image, and c is the XRD image.

[0059] Depend on Figure 2 It can be seen that the morphology and structure of V2O3 / C-Se remain intact, and the lattice fringes correspond to the (104) crystal plane of the hexagonal phase V2O3. This shows that the prepared V2O3 has good crystallinity and the crystal structure of V2O3 is not destroyed after selenization. The characteristic diffraction peaks in XRD match the standard card of V2O3 (JCPDF#34-0187), proving that the crystal has a high phase purity. XRD results show that no selenide is detected in the product, indicating that it has entered the carbon or V2O3 lattice in the form of heteroatoms.

[0060] Example 3 (Ce modification)

[0061] A method for preparing a positive electrode material for an aqueous zinc ion battery comprises the following steps:

[0062] S1. Take 0.5255g of ammonium metavanadate (NH4VO3), 0.2166g of cerium nitrate (Ce(NO3)3·6H2O), and 0.83g of terephthalic acid (PTA) and dissolve them in 25mL of anhydrous ethanol to obtain solution A; take 0.194g of citric acid monohydrate (CA) and dissolve it in 25mL of deionized water to obtain solution B. 10mL of HCl solution (concentration of 1mol / L) and solution B are added to solution A respectively and stirred thoroughly. After mixing evenly, hydrothermally react at 120℃ for 24h to obtain V-MOF precursor;

[0063] S2. The V-MOF precursor was placed in a crucible and carbonized under an inert atmosphere. The heating rate of the carbonization treatment was 5°C / min, the holding temperature was 700°C, and the holding time was 3 hours. The product was then naturally cooled to room temperature to obtain an aqueous zinc ion battery positive electrode material, which was recorded as V2O3 / C-Ce.

[0064] Example 4 (Ba modification)

[0065] A method for preparing a positive electrode material for an aqueous zinc ion battery comprises the following steps:

[0066] S1. Dissolve 0.5255 g of ammonium metavanadate (NH4VO3), 0.13 g of barium nitrate (Ba(NO3)2), and 0.83 g of terephthalic acid (PTA) in 25 mL of anhydrous ethanol to obtain solution A; dissolve 0.194 g of citric acid monohydrate (CA) in 25 mL of deionized water to obtain solution B. Add 10 mL of HCl solution (concentration of 1 mol / L) and solution B to solution A in sequence and stir thoroughly. After mixing evenly, hydrothermally react at 120 ° C for 24 h to obtain a V-MOF precursor.

[0067] S2. The V-MOF precursor is placed in a crucible and carbonized under an inert atmosphere. The heating rate of the carbonization treatment is 5°C / min, the holding temperature is 700°C, and the holding time is 3 hours. It is then naturally cooled to room temperature to obtain an aqueous zinc ion battery positive electrode material, which is recorded as V2O3 / C-Ba.

[0068] Test example

[0069] The electrode materials prepared in Examples 1 to 4 were assembled into a zinc ion battery in the following steps:

[0070] Take 14.378g of zinc sulfate heptahydrate (ZnSO4·7H2O) and dissolve it in 25mL of deionized water to prepare a 2mol / L electrolyte solution, which is recorded as Mn-free. 2+ Different amounts of manganese acetate were dissolved in 2 mL of the above electrolyte solution to prepare 0.2% (w / v), 0.5% (w / v), 1% (w / v), 2.5% (w / v), 5% (w / v) Mn 2+ content of electrolyte solution;

[0071] The zinc ion battery positive electrode material (electrode material prepared in Examples 1 to 4) and PVDF were mixed in a mass ratio of 85:15 and degassed to obtain a slurry; the slurry was coated on an aluminum foil with a loading of 1.0 mg / cm 2 , and then dried to obtain the positive electrode sheet; the positive electrode sheet was assembled into a zinc ion battery, the diaphragm was selected from a glass fiber diaphragm (the source was a commercially available glass fiber diaphragm), the electrolyte was the above-mentioned electrolyte solution, and the negative electrode was selected from a zinc sheet; after the assembly was completed, it was allowed to stand for 6 to 12 hours, and then an electrochemical test was performed.

[0072] In the assembled zinc ion battery: V2O3 / C represents the Mn-free 2+ The performance of the zinc ion battery assembled with the electrolyte solution and the electrode material of Example 1, V2O3 / C-Se represents the electrolyte solution without Mn 2+ The electrolyte solution and the relevant performance of the zinc ion battery assembled with the electrode material of Example 2, V2O3 / C-Mn represents Mn 2+ The performance of the zinc ion battery assembled with the electrolyte solution containing 0.5% of the content and the electrode material of Example 1, V2O3 / C-Se-Mn represents the Mn 2+ Relevant performance of the zinc ion battery assembled with the electrolyte solution with a content of 0.5% and the electrode material of Example 2.

[0073] Figure 3 The discharge capacity-cycle number curve comparison of the zinc ion battery assembled with the electrode materials of Example 1 and Example 2 at 1A / g constant current discharge, wherein a is the V2O3 / C and different Mn2+ Performance comparison diagram of the electrolyte combination with different content, b is the rate performance diagram of V2O3 / C-Se-Mn, c is the cycle diagram of V2O3 / C, V2O3 / C-Mn, and V2O3 / C-Se-Mn; d is the cycle diagram of V2O3 / C-Se and V2O3 / C-Se-Mn.

[0074] Depend on Figure 3 It can be seen that Mn in the electrolyte 2+ The participation of Mn greatly improved the cycle stability of the electrode material, and in subsequent experiments, 0.5% Mn 2+ The modified electrolyte was tested and it was found that the selenized material further improved the electrochemical performance. Figure 3 b shows that V2O3 / C-Se in Mn 2+ The modified electrolyte exhibits excellent rate performance; Figure 3 d shows that the addition of Mn in the electrolyte 2+ After that, the performance of V2O3 / C-Se is better than that of Mn-free 2+ Added case.

[0075] Figure 4 These are the impedance test results of zinc ion batteries assembled with the electrode materials of Examples 1 and 2.

[0076] Figure 4 It shows that the conductivity of the electrode material is improved after Se doping.

[0077] Figure 5 1 and 2 are Raman test results of the electrode materials prepared in Example 1 and Example 2, wherein a is V2O3 / C in Example 1 and b is V2O3 / C-Se in Example 2.

[0078] Figure 5 In the middle, the larger I D / I G The values ​​indicate that the carbon defects increase in the electrode material V2O3 / C-Se.

[0079] Figure 6 This is a cycle diagram of a zinc ion battery assembled with the electrode materials of Example 3 and Example 4, wherein a is Example 3 and b is Example 4.

[0080] Figure 6 In the process of assembling zinc ion batteries, the electrolyte used is Mn-free. 2+ of electrolyte solution.

[0081] Depend on Figure 6 It can be seen that compared with the V2O3 / C electrode material under the same electrolyte conditions, the material modified by adding transition metal ions has greatly improved the cycle life and capacity at a large current of 5A / g.

[0082] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A carbon-vanadium oxide zinc ion battery positive electrode material, characterized in that The positive electrode material includes a nanosheet stacking structure composed of carbon and V2O3 with an aspect ratio of 20 to 60.

2. A method for preparing the carbon-vanadium oxide zinc ion battery positive electrode material according to claim 1, characterized in that: The following steps are involved: The vanadium salt, ligand and regulator are mixed and subjected to hydrothermal reaction to obtain a V-MOF precursor; The V-MOF precursor is carbonized to obtain the carbon-vanadium oxide zinc ion battery positive electrode material.

3. The preparation method according to claim 2, characterized in that The vanadium salt is ammonium metavanadate; and / or the ligand is terephthalic acid; and / or the regulator contains hydrochloric acid and citric acid.

4. The preparation method according to claim 2, characterized in that The mass ratio of the vanadium salt, the ligand and the regulator is 3:4:

1.

5. The preparation method according to claim 2, characterized in that The temperature of the hydrothermal reaction is 120° C. and the time is 24 hours.

6. The preparation method according to claim 2, characterized in that The temperature of the carbonization treatment is 600-1000° C., the time is 2-8 hours, and the atmosphere is a protective atmosphere.

7. The preparation method according to claim 2, characterized in that After the carbonization treatment, the method further comprises a selenization treatment step, wherein the selenization treatment comprises: mixing the composite material obtained after the carbonization treatment with a selenium source and performing the selenization treatment.

8. The preparation method according to claim 7, characterized in that The selenium source in the selenization treatment includes selenium oxide or selenium; and / or the temperature of the selenization treatment is 550-850° C., and the time is 0.5-4 hours.

9. The preparation method according to claim 2, characterized in that Before the hydrothermal reaction, the method further comprises the step of adding metal doping ions; the metal doping ions include Fe, Co, Mn, Cu, Ce or Ba, etc.; and the molar ratio of the metal doping ions to the vanadium salt is 1:5-20.

10. Use of the carbon-vanadium oxide zinc ion battery positive electrode material according to claim 1 in a zinc ion battery.

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