Defect-rich tungsten oxide nanowire composite electrode, preparation method thereof and application of defect-rich tungsten oxide nanowire composite electrode in flow battery
By growing defect-rich tungsten oxide nanowires in situ on carbon-based materials, the problem of slow vanadium ion reaction at the negative electrode of vanadium redox flow batteries was solved, improving the energy efficiency and stability of the battery while reducing material costs.
Patent Information
- Application Number
- CN202511707017.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-02-06
AI Technical Summary
The sluggish vanadium ion reaction kinetics on the negative electrode side of the all-vanadium redox flow battery result in low power density and limited electrolyte utilization, thus restricting the overall economic improvement of the battery.
A defect-rich tungsten oxide nanowire composite electrode W18O49@CF was prepared by in-situ loading defect-rich tungsten oxide nanowires on the surface of a carbon-based material using a solvothermal method, which enhanced the electrocatalytic activity of vanadium ions.
It significantly improves the energy efficiency and cycle stability of the battery, reduces the manufacturing cost, and improves electrode performance through high specific surface area and high catalytic activity.
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Figure CN121484082A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of liquid flow battery materials, in particular to a defect-rich tungsten oxide nanowire composite electrode and a preparation method and application thereof in a liquid flow battery. BACKGROUND
[0002] With the rapid expansion of renewable energy installed capacity, the market demand for large-scale, long-time energy storage technology is increasingly urgent. The all-vanadium redox flow battery is considered to be one of the most promising large-scale energy storage technologies due to its outstanding advantages such as independent design of power and capacity, long cycle life, high safety, etc. However, the technology still faces key challenges such as low power density and limited electrolyte utilization, which restricts the further improvement of its overall economy. Among the many factors affecting the performance of the all-vanadium flow battery, the slow reaction kinetics of vanadium ions on the negative electrode is particularly prominent, which is the main bottleneck limiting the improvement of the battery power characteristics. Therefore, developing a negative electrode material with high catalytic activity is of great significance to improve the overall performance of the all-vanadium flow battery. SUMMARY
[0003] The present application aims to provide a defect-rich tungsten oxide nanowire composite electrode and a preparation method and application thereof in a liquid flow battery electrode material. Impurities attached to the carbon-based material are washed clean with a solvent such as deionized water or ethanol, and the treated carbon-based material is immersed in a tungsten-containing solution. The defect-rich tungsten oxide nanowire is loaded on the surface of the carbon-based material in situ using a solvothermal method to obtain W 18 O 49 @CF, which can significantly enhance the electrocatalytic activity of vanadium ions and thus improve the overall performance of the battery.
[0004] To achieve the above-mentioned application purposes, the technical solution adopted by the present application is as follows: a defect-rich tungsten oxide nanowire composite electrode is prepared by using a carbon-based material as a substrate and a solvothermal method in a tungsten ion-containing precursor solution.
[0005] A preparation method of a defect-rich tungsten oxide nanowire composite electrode, the method comprising: dissolving a tungsten salt in ethanol to obtain a tungsten ion-containing precursor solution; immersing a carbon-based material in the tungsten ion-containing precursor solution, stirring, and then placing it in a hydrothermal kettle for solvothermal treatment. After cooling to room temperature and washing, a defect-rich tungsten oxide nanowire composite electrode is obtained.
[0006] Further, the tungsten salt is WCl6
[0007] Further, the tungsten salt: ethanol solution = 0.1 g: (40 mL-60 mL) according to the solid-liquid ratio.
[0008] Further, the carbon-based material includes carbon paper, carbon felt, carbon cloth, and graphite felt.
[0009] Further, the solvothermal treatment is: heating to 180-250 DEG C at a heating rate of 2-15 DEG C / min, and holding for 15-26 h.
[0010] Further, the solvothermal treatment is: heating to 180-250 DEG C at a heating rate of 2-15 DEG C / min, and holding for 15-26 h.
[0011] The application provides application of a defect-rich tungsten oxide nanowire composite electrode as an electrode material in a flow battery.
[0012] Compared with the prior art, the application has the beneficial effects that:
[0013] 1. The defect-rich tungsten oxide nanowire composite electrode prepared by the application has raw materials that are easy to obtain and low in cost, and uses tungsten element as a precursor, which is widely available and low in price, thereby effectively reducing the preparation cost of the electrode material and providing an economic basis for large-scale application.
[0014] 2. The defect-rich tungsten oxide nanowire composite electrode prepared by the application has a simple process and stable structure, and the defect-rich tungsten oxide nanowire is grown in situ on a carbon-based electrode through a simple one-step hydrothermal method. The process simplifies the preparation process, and the in-situ growth makes the composite material firmly combined and high in structural stability.
[0015] 3. The defect-rich tungsten oxide nanowire composite electrode W 18 O 49 @CF prepared by the application significantly enhances the catalytic activity for the electrochemical reaction of vanadium ions compared with the defect-free tungsten oxide material WO3@CF, thereby comprehensively improving the energy efficiency and cycle stability of the battery. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 It is a scanning electron microscope graph of the original carbon felt CF electrode.
[0017] Figure 2 It is a scanning electron microscope graph of the defect-rich tungsten oxide nanowire composite carbon felt prepared in Example 1.
[0018] Figure 3 It is an XRD spectrum of the W 18 O 49 @CF powder prepared in Example 1.
[0019] Figure 4 It is a cyclic voltammogram of the original carbon felt CF, the defect-free tungsten oxide composite electrode WO3@CF and the defect-rich tungsten oxide nanowire composite electrode W 18 O 49 @CF of the application in a vanadium battery electrolyte.
[0020] Figure 5 For the original carbon felt CF and the W 18 O 49 Battery efficiency diagram of CF in all-vanadium redox flow battery. DETAILED DESCRIPTION
[0021] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in conjunction with the accompanying drawings and examples.
[0022] Example 1 A defect-rich tungsten oxide nanowire composite electrode (W 18 O 49 @CF)
[0023] (I) Preparation of a defect-rich tungsten oxide nanowire composite electrode
[0024] 1. Pretreatment
[0025] The carbon felt (CF) was soaked in deionized water and ethanol for cleaning, and dried for 12 h after cleaning to remove impurities on the carbon felt.
[0026] 2. Preparation of precursor solution
[0027] 0.1 g of WCl6 was added to 50 mL of anhydrous ethanol, and stirred for 20 min until WCl6 was completely dissolved to obtain a tungsten ion-containing precursor solution.
[0028] 3. Preparation of W 18 O 49 @CF
[0029] The pretreated carbon felt (CF) was immersed in the tungsten ion-containing precursor solution and stirred for 20 min. After stirring, the solution and the carbon felt were transferred to an autoclave together, heated to 220℃ at a heating rate of 5℃ / min, and kept at this temperature for 18 h. The carbon felt was taken out, repeatedly washed with deionized water, and dried in a vacuum environment for 12 h to obtain a defect-rich tungsten oxide nanowire composite electrode (W 18 O 49 @CF).
[0030] (II) Comparative Example - Defect-free tungsten oxide composite electrode WO3@CF
[0031] 1. Pretreatment:
[0032] The carbon felt (CF) was soaked in deionized water and ethanol for cleaning, and dried for 12 h after cleaning to remove impurities on the carbon felt.
[0033] 2. Preparation of immersion solution
[0034] Add 0.1g Na2WO4·2H2O to 50mL of anhydrous ethanol and stir for 20min until Na2WO4·2H2O is completely dissolved to obtain the impregnation solution.
[0035] 3. Preparation of WO3@CF
[0036] The pretreated carbon felt (CF) was immersed in the impregnation solution and stirred for 20 min. After stirring, the solution and carbon felt were transferred to a hydrothermal reactor and heated to 220°C at a rate of 5°C / min. The temperature was maintained at this temperature for 18 h, and then allowed to cool naturally to room temperature. The carbon felt was removed, repeatedly washed with deionized water, and dried in a vacuum environment for 12 h to obtain a defect-free tungsten oxide composite electrode (WO3@CF).
[0037] (iii) Characterization
[0038] like Figure 1 As shown, the untreated raw carbon felt (CF) has a relatively smooth fiber surface.
[0039] Figure 2 It is a defect-rich tungsten oxide nanowire composite carbon felt W 18 O 49 @CF scanning electron microscope image. By Figure 2 As can be seen, this application successfully prepared W nanowire structures in situ. 18 O 49 @CF electrode material. Compared to the smooth fibers of the original carbon felt, W 18 O 49 @CF fiber surface is covered with a layer of fine nanowires, conforming to W 18 O 49 As a characteristic morphology of monoclinic crystals, W 18 O 49 The fiber diameter of @CF did not change significantly. 18 O 49 The advantages of @CF in terms of surface morphology result in a larger reaction area, which is more conducive to the transport of electrolyte and charge.
[0040] Figure 3 For W 18 O 49 @CF powder XRD pattern. (Source: [Insert source here]) Figure 3 As can be seen, the XRD diffraction pattern shows W 18 O 49 The monoclinic phase crystal form is characterized by two diffraction peaks at 23.7° and 48.4°, corresponding to W, respectively. 18 O 49 The (010) and (020) crystal planes.
[0041] Example 2 W 18 O 49Application of CF as an electrode material in all-vanadium redox flow batteries
[0042] 1. Catalytic performance analysis
[0043] Cyclic voltammetry test conditions: CF, WO3@CF and W respectively 18 O 49 @CF is the working electrode, the counter electrode is a platinum sheet, and the reference electrode is a saturated calomel electrode (SCE, 0.24V vs. SHE); the working electrode, counter electrode, and reference electrode are respectively installed in a three-necked electrolytic cell at 0.1MV. 2+ Cyclic voltammetry was performed using a negative electrode electrolyte of +2M H2SO4 at a scan rate of 5 mV·s. -1 The result is as follows Figure 4 .
[0044] Figure 4 For CF, WO3@CF and W 18 O 49 Cyclic voltammetry curves of @CF in vanadium battery electrolyte. Figure 4 As can be seen, the CV curve of CF does not show obvious redox peaks, while WO3@CF improves catalytic activity, showing obvious redox peaks; compared with WO3@CF, W 18 O 49 The CV curve of @CF shows more obvious and symmetrical redox peaks. W 18 O 49 The CV curve of @CF shows a high peak current density and a small peak potential difference, indicating that it exhibits the best electrochemical activity for the redox reaction of vanadium ions at the negative electrode, reflecting excellent reaction kinetics, in which defect-rich tungsten oxide plays a role.
[0045] 2. Battery performance test
[0046] All-vanadium redox flow battery test conditions: positive electrode is original carbon felt, negative electrode is W 18 O 49 @CF, both the positive and negative electrodes use 3.5-valent vanadium redox flow battery electrolyte, which mainly contains 1.4 MV... 3.5+ +3M H2SO4; using 100mA·cm -2 200mA·cm -2 300mA·cm -2 400mA·cm -2 500mA·cm -2 The system was subjected to charge-discharge cycles at a current density of [value missing]. The charging cutoff condition was a voltage not exceeding 1.65V, and the discharging cutoff condition was a voltage not falling below 0.6V. The results are as follows: Figure 5 .
[0047] Figure 5 For the original carbon felt CF and the W 18 O 49 @CF in the battery efficiency diagram of the all-vanadium redox flow battery. From Figure 5 It can be seen that with the increase of current density, the energy efficiency of both gradually decreases, but the battery equipped with W 18 O 49 @CF electrode is always higher than that of the CF electrode, and the higher the current density, the greater the leading margin of the W 18 O 49 @CF electrode battery. At 300 mA·cm -2 The current density, the energy efficiency of the battery equipped with W 18 O 49 @CF can reach 77%, which is 14% higher than that of the battery with the original electrode material; when the current density reaches 400 mA·cm -2 And above, the battery equipped with the original carbon felt electrode cannot normally charge and discharge, while the battery equipped with W 18 O 49 @CF can still normally charge and discharge, and the energy efficiency reaches 71.6%, fully proving that W 18 O 49 @CF has excellent electrocatalytic activity and provides more active sites for the adsorption and reaction of vanadium ions.
[0048] The present application uses a simple and controllable hydrothermal method to realize one-step in-situ preparation of a defect-rich tungsten oxide nanowire composite electrode. The prepared W 18 O 49 @CF electrode has the advantages of high specific surface area, high catalytic activity, low resistance, etc., and exhibits excellent battery performance at high current density.
[0049] The present application introduces easily available tungsten oxide onto the surface of carbon felt nanofibers, further increases the specific surface area of the material, significantly improves its activity, thereby fully utilizes the potential of the material and substantially improves the performance of the electrode, while also effectively reduces the cost of the material. The hydrothermal treatment process further activates the defect-containing tungsten oxide nanowire modified carbon felt, enhances its electrocatalytic activity, thereby improves the performance of the electrode, significantly reduces the polarization phenomenon of the battery, and improves the energy conversion efficiency of the battery.
Claims
1. A defect-rich tungsten oxide nanowire composite electrode, characterized in that, The application discloses a carbon-based material as a substrate, and a rich-defect tungsten oxide nanowire composite electrode is prepared by a solvothermal method in a tungsten ion precursor solution.
2. The method of claim 1, wherein the method of preparing a defect-rich tungsten oxide nanowire composite electrode is characterized by, The preparation method comprises the following steps: dissolving a tungsten salt in ethanol to obtain a tungsten ion-containing precursor solution; immersing a carbon-based material in the tungsten ion-containing precursor solution, stirring, and then placing the carbon-based material in a hydrothermal kettle; performing a solvothermal treatment; cooling to room temperature; and washing to obtain the rich-defect tungsten oxide nanowire composite electrode.
3. The method of claim 2, wherein the method further comprises the step of: The tungsten salt is WCl6. 4. The method of claim 3, wherein the method further comprises the step of: The material solution ratio is tungsten salt: ethanol solution = 0.1 g: (40 mL-60 mL).
5. The method of claim 2, wherein the method further comprises the step of: The carbon-based material comprises carbon paper, carbon felt, carbon cloth and graphite felt. 6. The method of claim 2, wherein the method further comprises: The solvothermal treatment is heating at a temperature increasing rate of 2-15 ℃ / min to 180-250 ℃, and keeping the temperature for 15-26 h.
7. Application of the rich-defect tungsten oxide nanowire composite electrode in claim 1 as an electrode material in a flow battery.