Vanadium oxide positive electrode intercalation layer for battery and preparation method of vanadium oxide positive electrode intercalation layer

Abstract

The preparation method comprises the following steps: fully mixing vanadium pentoxide and electroactive molecules, uniformly stirring and ultrasonically dispersing the mixture in an aqueous solution, carrying out a hydrothermal reaction on the obtained suspension, and filtering, washing and drying after the reaction to obtain the vanadium oxide positive electrode intercalation layer for the battery. And finally, the electroactive molecule intercalated vanadium pentoxide is obtained. Due to the intercalation of the electroactive molecules, the lattice spacing of vanadium pentoxide is enlarged, so that ions can be quickly migrated and diffused in the material. Compared with pure vanadium pentoxide, the vanadium pentoxide positive electrode material shows quicker reaction kinetics in the aqueous zinc ion battery through intercalation of the electroactive molecules, so that the rate capability is greatly improved.

Description

Technical Field

[0001] The present invention generally relates to the field of aqueous zinc ion energy storage batteries, and in particular to a method for intercalating vanadium pentoxide into electroactive molecules. Background Art

[0002] In the past few decades, lithium-ion batteries have dominated the energy storage field with their advantages such as high energy density, good cycle stability, and fast charge and discharge speed. However, lithium resources are scarce and expensive, and most lithium batteries use volatile and toxic organic electrolytes, which has hindered further development. Aqueous zinc-ion batteries (AZIBs), as an emerging energy storage technology, have attracted widespread attention in the field of electrochemical energy storage in recent years. Compared with traditional lithium-ion batteries, AZIBs have significant advantages such as low cost, high safety, abundant resources and environmental friendliness. However, the commercialization process of AZIBs still faces many challenges, among which the performance bottleneck of positive electrode materials is particularly prominent. Vanadium pentoxide (V2O5), as a type of positive electrode material with high theoretical capacity and good redox activity, has become one of the hot spots in AZIBs research. However, the low electronic conductivity and diffusion coefficient of V2O5 inhibit the Zn 2+ The embedding and extraction of zinc ions may cause the layered V2O5 to collapse. These problems seriously limit the comprehensive performance and application prospects of AZIBs.

[0003] According to current research, the main reasons for the decline in electrochemical performance of inorganic positive electrode materials are dissolution, structural collapse, weak electronic conductivity, slow ion transmission rate, etc., which can be solved by structural engineering methods such as interlayer intercalation, element doping, defect regulation, surface coating, construction of composite structure and morphology regulation. The present invention uses the strategy of organic intercalation for optimization, and introduces specific electroactive molecules or ions into the interlayer of V2O5 through hydrothermal reaction, thereby achieving effective regulation of the lattice spacing of V2O5 without destroying its original structure, providing a more spacious channel for the rapid transmission of zinc ions, and improving the stability of its crystalline structure. In addition, the introduced 5,6,11,12,17,18-hexaazatrinaphthene-2,8,14-tricarboxylic acid (3QA) electroactive molecules add additional redox active sites, further improving the electrochemical performance of the positive electrode material. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing vanadium pentoxide positive electrode and propose a method of using electroactive molecular intercalation, which can not only expand the vanadium pentoxide lattice spacing and improve the reaction kinetics, but also will not destroy the redox activity and cycle stability of the electrode material.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] In a first aspect, a method for preparing an intercalation layer of a vanadium oxide positive electrode for a battery according to the present invention comprises the following steps:

[0007] The vanadium pentoxide and the electroactive molecules are fully mixed, and the mixture is uniformly stirred and ultrasonically dispersed in an aqueous solution, the resulting suspension is subjected to a hydrothermal reaction, and after the reaction, it is filtered, washed, and dried to finally obtain a vanadium pentoxide powder intercalated with the electroactive molecules.

[0008] Furthermore, the molar ratio of the electroactive molecule to vanadium pentoxide is 1:3-5.

[0009] Furthermore, the electroactive molecule is any one of 5,6,11,12,17,18-hexaazatriaphthene-2,8,14-tricarboxylic acid (3QA), diazaanthracene (DAP) and 2,3-diaminophenolazine (2,3-DAP), preferably 5,6,11,12,17,18-hexaazatriaphthene-2,8,14-tricarboxylic acid.

[0010] Furthermore, the stirring time is 30 min to 60 min.

[0011] Furthermore, the ultrasonic dispersion time is 30 min to 60 min.

[0012] Furthermore, the hydrothermal reaction temperature is 140-160°C.

[0013] Furthermore, the hydrothermal reaction time is 12 to 24 hours.

[0014] In a second aspect, the present invention provides an intercalation layer of a vanadium oxide positive electrode prepared by the method described in the first aspect.

[0015] In a third aspect, the present invention provides the use of the intercalation layer of the vanadium oxide positive electrode prepared by the method described in the first aspect, which is applied as a positive electrode material to an aqueous zinc ion battery to eliminate the inherent defects of the vanadium pentoxide positive electrode material and improve its electrochemical performance.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The raw materials used in the present invention are low-cost and environmentally friendly, the preparation process involves few steps, the operation is simple, and large-scale production is possible.

[0018] 2. The lattice spacing of the vanadium pentoxide positive electrode of the electroactive molecular intercalation of the present invention is significantly widened, which is beneficial to the transfer and diffusion of ions within the structure.

[0019] 3. The electroactive molecular intercalated vanadium pentoxide positive electrode of the present invention has obvious application advantages in aqueous zinc ion batteries and has excellent reaction kinetics and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the material structure of V2O5-3QA of the present invention in Example 1;

[0021] Figure 2 The Fourier transform infrared spectrum (FTIR) of V2O5-3QA prepared in Example 1, including relevant comparative spectra of V2O5 and 3QA;

[0022] Figure 3 The X-ray photoelectron spectrum (XPS) of V2O5-3QA prepared in Example 1 includes relevant comparative spectra of V2O5 and 3QA;

[0023] Figure 4 The X-ray diffraction spectrum (XRD) of V2O5-3QA prepared in Example 1, including the relevant comparative spectra of V2O5 and 3QA;

[0024] Figure 5 This is a transmission electron microscopy (TEM) image of V2O5-3QA prepared in Example 1.

[0025] Figure 6 The cyclic voltammogram (CV) of V2O5-3QA prepared in Example 1 as the positive electrode material in an aqueous zinc ion battery, with a scan rate of 0.1 mV s -1 , 0.2mV s -1 , 0.4mV s -1 , 0.6mV s -1 , 0.8mV s -1 , 1.0mV s -1 ;

[0026] Figure 7 This is the electrochemical impedance spectrum (EIS) of the V2O5-3QA prepared in Example 1 as the positive electrode material in an aqueous zinc ion battery, including relevant comparative spectra of V2O5 and 3QA.

[0027] Figure 8 This is a rate performance diagram of the V2O5-3QA prepared in Example 1 as a positive electrode material in an aqueous zinc ion battery, including relevant comparison diagrams of V2O5 and 3QA. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0029] Example 1

[0030] Combination Figure 1 This example provides the preparation process of V2O5-3QA, which is as follows:

[0031] V2O5 (2.4 mmol) and 3QA (0.6 mmol) were mixed evenly, and then 35 ml of deionized water was added and stirred for 30 minutes and ultrasonicated for 30 minutes. The resulting suspension was sealed in a polytetrafluoroethylene liner and placed in a hydrothermal reactor for a hydrothermal reaction at 140°C for 24 hours. After the reaction was completed, it was filtered and washed with deionized water, ethanol and acetone respectively, and then the solid product V2O5-3QA was placed at 60°C and vacuum dried for 24 hours.

[0032] Example 2

[0033] V2O5 (2.4 mmol) and DAP (0.6 mmol) were mixed evenly, and then 35 ml of deionized water was added and stirred for 30 minutes and ultrasonicated for 30 minutes. The resulting suspension was sealed in a polytetrafluoroethylene liner and placed in a hydrothermal reactor for a hydrothermal reaction at 140°C for 24 hours. After the reaction was completed, it was filtered and washed with deionized water, ethanol and acetone respectively, and then the solid product was placed at 60°C and vacuum dried for 24 hours.

[0034] Example 3

[0035] V2O5 (2.4 mmol) and 2,3-DAP (0.6 mmol) were mixed evenly, and then 35 ml of deionized water was added and stirred for 30 minutes and ultrasonicated for 30 minutes. The resulting suspension was sealed in a polytetrafluoroethylene liner and placed in a hydrothermal reactor for a hydrothermal reaction at 140°C for 24 hours. After the reaction was completed, it was filtered and washed with deionized water, ethanol and acetone respectively, and then the solid product was placed at 60°C and vacuum dried for 24 hours.

[0036] The V2O5-3QA in Example 1 was mixed with conductive carbon black and polyvinylidene fluoride in a mass ratio of 6:3:1, N-methyl-2-pyrrolidone was added dropwise and grinding was continued until the powder was converted into a uniform slurry, and then the slurry was evenly coated on a titanium foil, and then placed under vacuum drying at 60°C for 24 hours, and finally used as a V2O5-3QA positive electrode sheet. The prepared V2O5-3QA positive electrode sheet was paired with a zinc metal sheet, and a 2M Zn(CF3SO3)2 aqueous solution was used as an electrolyte to assemble an aqueous zinc ion battery. The V2O5-3QA was characterized and measured, and the electrochemical performance of the assembled zinc ion battery was tested.

[0037] Figure 2The FTIR spectra of V2O5, 3QA and V2O5-3QA after hydrothermal treatment show that the VO bond of V2O5 and the C=N bond of 3QA can be observed in the V2O5-3QA sample.

[0038] Figure 3 The X-ray photoelectron spectra (XPS) of V2O5, 3QA and V2O5-3QA after hydrothermal treatment show that the V element of V2O5 and the N element of 3QA exist in the V2O5-3QA sample.

[0039] Figure 4 The X-ray diffraction spectra (XRD) of V2O5, 3QA and V2O5-3QA after hydrothermal treatment show that the 001 crystal plane in the V2O5-3QA sample has significantly shifted to a smaller angle than that in V2O5, proving that the lattice spacing has expanded.

[0040] Figure 5 This is a transmission electron microscopy (TEM) image of the V2O5-3QA sample. The results show that the interplanar spacing of the V2O5-3QA sample has expanded to 1.13nm, which is larger than the lattice spacing of V2O5 (0.43nm).

[0041] Figure 6 The cyclic voltammogram (CV) of V2O5-3QA as a cathode material in an aqueous zinc-ion battery. The results show that the V2O5-3QA cathode exhibits excellent redox reversibility in electrochemical tests.

[0042] Figure 7 The electrochemical impedance spectra (EIS) of V2O5, 3QA and V2O5-3QA as positive electrode materials in aqueous zinc-ion batteries after hydrothermal treatment show that the V2O5-3QA positive electrode has the smallest charge transfer resistance.

[0043] Figure 8 The specific capacities of V2O5, 3QA and V2O5-3QA as positive electrode materials in aqueous zinc-ion batteries at different current densities after hydrothermal treatment. The results show that the V2O5-3QA positive electrode has the best rate performance.

Claims

1. A method for preparing an intercalation layer of a vanadium oxide positive electrode for a battery, characterized in that: The following steps are involved: The vanadium pentoxide and the electroactive molecules are fully mixed, and the mixture is uniformly stirred and ultrasonically dispersed in an aqueous solution, the resulting suspension is subjected to a hydrothermal reaction, and after the reaction, it is filtered, washed, and dried to finally obtain a vanadium pentoxide powder intercalated with the electroactive molecules.

2. The method according to claim 1, characterized in that The molar ratio of the electroactive molecule to vanadium pentoxide is 1:3-5.

3. The method according to claim 1, characterized in that The electroactive molecule is any one of 5,6,11,12,17,18-hexaazatrinaphthylene-2,8,14-tricarboxylic acid, diazaanthracene and 2,3-diaminophenolazine.

4. The method according to claim 1, characterized in that The electroactive molecule is 5,6,11,12,17,18-hexaazatrinaphthene-2,8,14-tricarboxylic acid.

5. The method according to claim 1, characterized in that The stirring time is 30 min to 60 min.

6. The method according to claim 1, characterized in that The ultrasonic dispersion time is 30 min to 60 min.

7. The method according to claim 1, characterized in that The hydrothermal reaction temperature is 140~160 o C.

8. The method according to claim 1, characterized in that The hydrothermal reaction time is 12 to 24 h.

9. An intercalation layer of a vanadium oxide positive electrode prepared by the method according to any one of claims 1 to 8.

10. Use of the vanadium oxide positive electrode intercalation prepared by the method according to any one of claims 1 to 8, characterized in that: It is used as a positive electrode material in aqueous zinc-ion batteries.

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