Preparation method and application of organic molecule metal ion double-intercalation vanadium-based oxide positive electrode material

Abstract

The invention discloses a preparation method and application of an organic molecule metal ion double-intercalation vanadium-based oxide positive electrode material, and the method comprises the following steps: S1, adding 2, 5-hexanedione, aluminum chloride and a vanadium-based oxide into deionized water according to a preset molar ratio, and stirring to a uniform state; s2, continuously stirring the solution prepared in the step S1, controlling the stirring rate, and dropwise adding diluted hydrochloric acid to adjust the pH value to a target pH value; and S3, washing and drying the material prepared in the step S2 to obtain the organic molecule metal ion double-intercalation vanadium-based oxide positive electrode material. The vanadium-based oxide positive electrode material is optimized by applying an organic molecule metal ion double-intercalation strategy, the skeleton is greatly stabilized, the bonding mode of the vanadium-based oxide is optimized, more Zn < 2 + > ion intercalation active sites are provided, and the electrochemical performance of the material is improved. The prepared organic molecule metal ion double-intercalation vanadium-based oxide positive electrode material shows excellent cycling stability, relatively high specific capacity and excellent rate capability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of zinc ion batteries, and particularly relates to a preparation method and application of an organic molecule metal ion double intercalation vanadium-based oxide positive electrode material. BACKGROUND

[0002] Under the background of increasingly exhausted fossil fuels and increasingly severe environmental problems, environmental and energy problems have become important focuses for the future development of human society. Reducing dependence on fossil fuels and strengthening ecological and environmental protection are inevitable trends. Therefore, people gradually turn their attention to the development and utilization of new energy. New energy such as solar energy and wind energy can be continuously converted into electric power, but the storage and large-scale application of such electric power are limited by economic costs, and the energy storage problem has become a strategic problem. Aqueous zinc ion batteries have a large theoretical specific capacity, low redox potential, high ionic conductivity of aqueous electrolyte, and high stability of metal zinc in an atmospheric environment, can be directly used as a negative electrode material of an aqueous zinc battery, has a high safety level, and has advantages such as abundant zinc reserves and low price, and is highly concerned and has high application value and development prospect in the field of large-scale energy storage. However, the strong repulsive force between Zn 2+ ions and positive electrode host materials leads to a high energy barrier, which hinders the kinetics of Zn 2+ ion intercalation / deintercalation and causes structural distortion, thereby limiting the development and practical application. SUMMARY

[0003] To solve the above problems, the application provides a preparation method and application of an organic molecule metal ion double intercalation vanadium-based oxide positive electrode material. The application optimizes the vanadium-based oxide positive electrode material by using the strategy of organic molecule metal ion double intercalation, greatly stabilizes the skeleton, optimizes the bonding mode of the vanadium-based oxide, and provides more Zn 2+ ion intercalation active sites. The prepared organic molecule metal ion double intercalation vanadium-based oxide positive electrode material has excellent cycle stability, high specific capacity, and excellent rate performance.

[0004] To achieve the above purpose, the following technical solutions are adopted in the application.

[0005] A preparation method of an organic molecule metal ion double intercalation vanadium-based oxide positive electrode material, comprising the following steps:

[0006] S1, according to a preset molar ratio, 2,5-hexanedione, aluminum chloride and vanadium-based oxide are added to deionized water, and stirring is performed until a uniform state is reached;

[0007] S2, continuously stirring the solution prepared in step S1, controlling the stirring rate, and adding dilute hydrochloric acid dropwise to adjust the pH value to a target pH value; wherein the continuous stirring time is a target time, and the stirring rate is a target rate.

[0008] S3, washing and drying the material prepared in step S2 to obtain the organic molecule metal ion double intercalation vanadium-based oxide positive electrode material.

[0009] Preferably, the vanadium-based oxide in step S1 adopts vanadium pentoxide, ammonium metavanadate or sodium vanadate.

[0010] Preferably, when the vanadium-based oxide in step S1 adopts ammonium metavanadate, the molar ratio of the vanadium-based oxide, 2,5-hexanedione and aluminum chloride is 4:1:1.

[0011] Preferably, the target pH value in step S2 is 1.6-2.

[0012] Preferably, the target time length in step S2 is 60-80h.

[0013] Preferably, the target speed in step S2 is 600-700rmp.

[0014] Preferably, the washing in step S3 adopts deionized water and ethanol.

[0015] An organic molecule metal ion double intercalation vanadium-based oxide positive electrode material is prepared by the preparation method of the organic molecule metal ion double intercalation vanadium-based oxide positive electrode material.

[0016] A water-based zinc ion battery, wherein the positive electrode material of the water-based zinc ion battery adopts the organic molecule metal ion double intercalation vanadium-based oxide positive electrode material.

[0017] Preferably, the electrolyte of the water-based zinc ion battery adopts zinc trifluoromethane sulfonate; and the negative electrode of the water-based zinc ion battery adopts zinc foil.

[0018] After the above technical solution, the present application has the following beneficial effects:

[0019] 1. The present application modifies ammonium metavanadate, and uses the strategy of organic molecule metal ion double intercalation to embed Al 3+ metal ions and 2,5-hexanedione organic molecules into the interlayer channel at the same time, the intercalation of Al 3+ ions expands the interlayer distance and plays the role of layer pillar, greatly stabilizing the skeleton, the introduction of 2,5-hexanedione optimizes the bonding mode of vanadium-based oxide, and the carbonyl provides more Zn 2+ ion intercalation active sites, under the joint action of Al 3+ ion and 2,5-hexanedione molecules, effectively improves the electrochemical performance of the vanadium-based oxide positive electrode material.

[0020] 2. This invention uses room temperature stirring to synthesize vanadium-based oxide cathode materials in a non-hydrothermal manner, which is simple to operate and can be mass-produced.

[0021] 3. The organic molecular metal ion double intercalation vanadium-based oxide cathode material prepared by this invention exhibits excellent cycle stability, high specific capacity, and excellent rate performance. Attached Figure Description

[0022] Figure 1 The XRD patterns are of the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of this invention.

[0023] Figure 2 The infrared spectra of the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of this invention are shown below.

[0024] Figure 3 XPS spectra of V 2p of the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention;

[0025] Figure 4 EIS diagrams of aqueous zinc-ion batteries assembled from the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention;

[0026] Figure 5 A comparison diagram of the diffusion coefficients of aqueous zinc-ion batteries assembled from the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention;

[0027] Figure 6 Comparison of pseudocapacitive contribution rates of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention.

[0028] Figure 7 The first constant current charge-discharge curves of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention at a current density of 0.1 Ag⁻¹.

[0029] Figure 8 The cycling performance of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 of the present invention is shown at a current density of 5 Ag⁻¹.

[0030] Figure 9 An aqueous zinc-ion battery assembled using the vanadium-based oxide cathode material prepared in Example 1 of this invention was tested at 5Ag. -1 SEM images of the positive electrode surface after 1000 and 3000 cycles at current density;

[0031] Figure 10Rate performance comparison of aqueous zinc ion batteries assembled with the vanadium-based oxide positive electrode material prepared for the comparative example 1, 2 and example 1 of the present application;

[0032] Figure 11 In-situ XRD pattern of the aqueous zinc ion battery assembled with the vanadium-based oxide positive electrode material prepared for the example 1 of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0034] As shown in Figures 1 to 11 .

[0035] Example 1

[0036] A preparation method of an organic molecule metal ion double intercalation vanadium-based oxide positive electrode material, comprising the following steps:

[0037] Ammonium metavanadate (3 mmol), 2,5-hexanedione (0.75 mmol) and aluminum chloride (0.75 mmol) are uniformly mixed, then placed in a 100 ml beaker and dissolved in deionized water with vigorous stirring. Slowly add hydrochloric acid to adjust the pH value to 1.8, continuously stir at a stirring rate of 650 rpm at room temperature for 72 h. Wash with deionized water, ethanol, deionized water in sequence, then vacuum dry at 60°C for 12 h to obtain the organic molecule metal ion double intercalation vanadium-based oxide positive electrode material.

[0038] Comparative example 1

[0039] Ammonium metavanadate (3 mmol) is placed in a 100 ml beaker, dissolved in water with vigorous stirring, and hydrochloric acid is slowly added to adjust the pH value to 1.8. Stir continuously at a stirring rate of 650 rpm at room temperature for 72 h, and then wash with deionized water, ethanol, respectively, and then vacuum dry at 60°C for 12 h to obtain the vanadium-based oxide positive electrode material.

[0040] Comparative example 2

[0041] Ammonium metavanadate (3 mmol) and aluminum chloride (0.75 mmol) are uniformly mixed, placed in a 100 ml beaker, dissolved in water with vigorous stirring, and hydrochloric acid is slowly added to adjust the pH value to 1.8. Stir continuously at a stirring rate of 650 rpm at room temperature for 72 h, and then wash with deionized water, ethanol, respectively, and then vacuum dry at 60°C for 12 h to obtain the vanadium-based oxide positive electrode material.

[0042] The vanadium-based oxide cathode materials obtained in Comparative Examples 1, 2, and 1 were ground uniformly using a mortar and pestle. The active material, Ketjen black, and PVDF binder were mixed in a mass ratio of 7:2:1, and an appropriate amount of N-methyl-2-pyrrolidone (NMP) was added to disperse the mixture. The cathode slurry was stirred at 600 rpm for 6 hours at room temperature. Then, using a 150 μm gap coater, the mixed slurry was uniformly coated onto a 10 μm thick titanium foil. The coated cathode sheet was then dried in a vacuum oven at 60°C for 6 hours, and cooled to room temperature to obtain the vanadium-based oxide cathodes of Comparative Examples 1, 2, and 1. The cooled cathodes were cut into vanadium-based oxide sheets with a diameter of 12 mm using a cutting machine for use in the assembly of full cells.

[0043] Aqueous zinc-ion button cells were assembled in the following order: CR2032 negative electrode shell, zinc sheet (80μm thick), glass fiber separator (675μm thick), electrolyte, vanadium-based oxide positive electrode, stainless steel sheet, spring sheet, and CR2032 positive electrode shell. The cells were then subjected to long-cycle testing and electrochemical performance testing at room temperature using the Xinwei charge-discharge testing system.

[0044] Test Example 1

[0045] The vanadium-based oxide cathode materials prepared in Comparative Example 1, Comparative Example 2, and Example 1 were subjected to XRD tests, and the XRD patterns obtained are shown below. Figure 1 As shown.

[0046] Depend on Figure 1 It can be seen that no new phase peaks were observed after guest molecule doping, and the integrity of the layered structure was maintained. All diffraction peaks of the vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2, and 1 are consistent with those of the monoclinic NH4V4O4. 10 Corresponding to the characteristic peaks (JCPDF No. 31-0075), based on the 2θ angle position of the characteristic diffraction peaks, the interplanar spacing of (001) in Comparative Example 1 was calculated to be 1.08 nm. In contrast, the peaks at (001) in Comparative Example 2 and Example 1 both showed a significant negative shift, which means that the corresponding interlayer spacing increased significantly. Al was introduced into Comparative Example 1. 3+ After ionization, the interlayer spacing of the (001) crystal plane in Comparative Example 2 increased to 1.38 nm, while in Example 1, due to Al... 3+ Due to the strategy of intercalation ion competition, the interlayer spacing of the ions and 2,5-hexanedione molecules is slightly smaller than that of Comparative Example 2, with an interlayer spacing of 1.35 nm corresponding to the (001) crystal plane.

[0047] Test Example 2

[0048] The vanadium-based oxide positive electrode materials prepared from Comparative Example 1, Comparative Example 2 and Example 1 were respectively subjected to infrared spectrum test, and the obtained infrared spectrum graphs are shown in Figure 2 .

[0049] From Figure 2 it can be seen that the peak at 756 cm -1 is attributed to the symmetric stretching vibration of V-O-V bond, and the peak at 985 cm -1 is the typical V-O stretching vibration. The peaks at 1413 and 3189 cm -1 come from the bending vibration of N-H bond, and since the Al 3+ ions and 2,5-hexanedione molecules replace the interlayer part of NH4 + , the peak intensity of Example 1 and Comparative Example 2 is weakened, and the peak at 1612 cm -1 is derived from the stretching vibration of O-H bond. In Example 1, it can be found that the peak intensity at this position is obviously increased, which is because the doping of 2,5-hexanedione molecules introduces carbonyl groups, the carbonyl groups and metal ions are coordinated, and the absorption peak thereof is red-shifted to the position of about 1610 cm -1 , which confirms the synergistic interaction between Al 3+ ions and 2,5-hexanedione molecules.

[0050] Test Example 3

[0051] The vanadium-based oxide positive electrode materials prepared from Comparative Example 1, Comparative Example 2 and Example 1 were respectively subjected to XPS test, and the obtained V 2p XRD graphs are shown in Figure 3 .

[0052] From Figure 3 it can be seen that the spectrum exists V 4+ deconvolution peaks (516.8 eV and 524.2 eV) and V 5+ deconvolution peaks (517.8 eV and 525.5 eV) at the same time, wherein the peak area ratio of V 4+ and V 5+ of Comparative Example 1 and Comparative Example 2 is relatively close, and the ratio of V 4+ deconvolution peak and V5+ deconvolution peak in Example 1 is obviously increased compared with the control group. The increase of V 4+ ratio in Example 1 can be attributed to the introduction of 2,5-hexanedione, and the intercalation of 2,5-hexanedione can reduce part of V 5+ , and the increase of V 4+ ratio indicates that more oxygen vacancies are generated after intercalation.

[0053] Test Example 4

[0054] EIS tests were performed on aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1, respectively.

[0055] Figure 4 Electrochemical impedance spectroscopy (EIS) results of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 show that Example 1 has the lowest charge transfer resistance.

[0056] Test Example 5

[0057] The aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 were subjected to GITT tests and the zinc ion diffusion coefficients were calculated.

[0058] Figure 5 The GITT test results and zinc ion diffusion coefficients of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2, and Example 1 are shown. The lgDZn values ​​for Comparative Examples 1 and 2 are also displayed. 2+ The values ​​are between -11.3 and -9.4 and -11.3 and 9.2, respectively, while the lgDZn of the positive electrode in Example 1... 2+ The values ​​are higher, ranging from -11.0 to -9.1. In Comparative Examples 1 and 2, the charge / discharge ratio of lgDZn... 2+ The significant differences in values ​​indicate that there are a large number of irreversible intercalations during the cycling process, and that the intercalation of zinc ions is more difficult than their deintercalation.

[0059] Test Example 6

[0060] The pseudocapacitive contribution rates of aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 were compared.

[0061] Depend on Figure 6 It can be seen that as the scan rate increases from 0.2 mV / s... -1 Increased to 1mV s -1 The pseudocapacitive contribution rate of the aqueous zinc-ion button batteries prepared in Comparative Examples 1, 2 and 1 gradually increased, with the pseudocapacitive contribution rate of Example 1 being the highest, indicating its excellent kinetic performance.

[0062] Test Example 7

[0063] Aqueous zinc-ion batteries assembled with vanadium-based oxide cathode materials prepared in Comparative Examples 1, 2 and Example 1 were subjected to constant current charge-discharge tests.

[0064] Figure 7 The figures show that Comparative Example 1, Comparative Example 2, and Example 1 were within a voltage range of 0.2-1.6V and a voltage of 0.1Ag.-1 The constant current charge-discharge curve of Example 1 electrode at a current density of 0.1 Ag -1 The discharge capacity of Example 1 electrode at a current density of 0.1 Ag -1 Compared with Comparative Example 1 and Comparative Example 2, Example 1 exhibits higher specific capacity and working voltage.

[0065] Test Example 8

[0066] The aqueous zinc ion batteries assembled by the vanadium-based oxide positive electrode materials prepared by Comparative Example 1, 2 and Example 1 respectively were subjected to constant current charge-discharge test.

[0067] Figure 8 The cycle diagram of the aqueous zinc ion batteries assembled by the vanadium-based oxide positive electrode materials prepared by Comparative Example 1, 2 and Example 1 at a current density of 5 Ag -1 The initial discharge capacity of Example 1 electrode at a current density of 5 Ag -1 The initial discharge capacity of Example 1 electrode at a current density of 5 Ag -1 The maximum capacity of 247 mAh g -1 The discharge capacity after 8000 cycles was 201 mAh g -1 The capacity retention rate was as high as 83%. Compared with the cycle stability and specific capacity of Comparative Example 2 electrode, the overall performance of Example 1 electrode was comprehensively improved. After reaching the maximum capacity of 200 mAh g -1 The capacity retention rate was only 28% after 3000 cycles under the same current density.

[0068] Test Example 9

[0069] The electrode sheets of the aqueous zinc ion battery assembled by Example 1 after 1000 cycles and 3000 cycles at a current density of 5 Ag -1 The electrode sheets of the aqueous zinc ion battery assembled by Example 1 after 1000 cycles and 3000 cycles at a current density of 5 Ag

[0070] As shown in Figure 9 The scanning electron microscope (SEM) of the electrode of the aqueous zinc ion battery assembled by Example 1 after 1000 cycles and 3000 cycles at a current density of 5 Ag -1 The scanning electron microscope (SEM) of the electrode of the aqueous zinc ion battery assembled by Example 1 after 1000 cycles and 3000 cycles at a current density of 5 Ag 2+ The scanning electron microscope (SEM) of the electrode of the aqueous zinc ion battery assembled by Example 1 after 1000 cycles and 3000 cycles at a current density of 5 Ag

[0071] Test Example 10

[0072] The water-based zinc ion battery assembled with the vanadium-based oxide positive electrode material prepared in Example 1 was subjected to rate performance test.

[0073] Figure 10 The water-based zinc ion button cell prepared in Example 1 showed excellent rate performance, with discharge capacity of 412, 327, 289, 232 and 172 mAh g-1 at current density of 0.1, 0.5, 1, 2 and 5 Ag-1 -1 , respectively. -1 When the current density was changed from 5 Ag-1 -1 back to 0.1 Ag-1 -1 , the discharge capacity recovered to 443 mAh g-1 -1 , with recovery rate of 109%. In comparison, the discharge capacity of Comparative Example 2 and Comparative Example 1 at the same current density was 315, 327, 278, 230 and 114 mAh g-1 -1 , and 370, 311, 266, 215 and 163 mAh g-1 -1 , respectively.

[0074] Test Example 11

[0075] The vanadium-based oxide positive electrode material prepared in Example 1 was subjected to in-situ XRD test.

[0076] Figure 11 The in-situ XRD test of the vanadium-based oxide positive electrode material prepared in Example 1 during the first charge-discharge cycle showed that the (110) peak at 24.6° gradually moved to the left to 24° during discharging, due to the lattice expansion caused by the intercalation of zinc ions, and the peak moved reversibly to the original position during charging, which indicated that the vanadium-based oxide positive electrode material prepared in Example 1 had good structural stability.

[0077] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, which should be encompassed within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material, characterized in that, Includes the following steps: S1. According to the preset molar ratio, add 2,5-hexanedione, aluminum chloride and vanadium-based oxide to deionized water and stir until homogeneous; S2. Continuously stir the solution prepared in step S1, control the stirring rate, and add dilute hydrochloric acid dropwise to adjust the pH value to the target pH value; wherein, the continuous stirring time is the target duration, and the stirring rate is the target rate; S3. Wash and dry the material prepared in step S2 to obtain an organic molecular metal ion double intercalation vanadium-based oxide cathode material.

2. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 1, characterized in that: The vanadium-based oxide mentioned in step S1 is vanadium pentoxide, ammonium metavanadate, or sodium vanadate.

3. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 2, characterized in that: In step S1, when ammonium metavanadate is used as the vanadium-based oxide, the molar ratio of vanadium-based oxide, 2,5-hexanedione, and aluminum chloride is 4:1:

1.

4. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 1, characterized in that: The target pH value in step S2 is 1.6-2.

5. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 1, characterized in that: The target duration in step S2 is 60-80 hours.

6. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 1, characterized in that: The target rate in step S2 is 600-700 rpm.

7. The method for preparing an organic molecular metal ion double-intercalated vanadium-based oxide cathode material as described in claim 1, characterized in that: In step S3, deionized water and ethanol are used for washing.

8. An organic-molecule metal ion double-intercalated vanadium-based oxide cathode material, characterized in that: The organic-molecule metal ion double-intercalated vanadium-based oxide cathode material is prepared using the preparation method of the organic-molecule metal ion double-intercalated vanadium-based oxide cathode material as described in any one of claims 1-7.

9. An aqueous zinc-ion battery, characterized in that: The positive electrode material of the aqueous zinc-ion battery is the organic molecular metal ion double intercalation vanadium-based oxide positive electrode material as described in claim 8.

10. An aqueous zinc-ion battery as described in claim 9, characterized in that: The electrolyte of the aqueous zinc-ion battery is zinc trifluoromethanesulfonate; the negative electrode of the aqueous zinc-ion battery is zinc foil.

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