An ultralong H2V3O8 nanowire, its preparation method and application

Abstract

This invention belongs to the field of nanowire technology, and provides an ultralong H2V3O8 nanowire, its preparation method, and its application. A vanadium source, reducing agent, and solvent are mixed to obtain a solution; the solution undergoes a hydrothermal reaction, followed by sequential washing and drying to obtain ultralong H2V3O8 nanowires. The preparation method of the ultralong H2V3O8 nanowires of this invention has advantages such as simple preparation process, low energy consumption, short time cycle, easy process control, and high purity of the obtained product. The aqueous zinc ion ultralong H2V3O8 nanowire cathode material exhibits excellent rate performance, meeting both high capacity requirements and rapid charge-discharge capabilities, with good cycle stability.

Description

Technical Field

[0001] This invention relates to the field of nanowire technology, and in particular to an ultralong H2V3O8 nanowire, its preparation method, and its application. Background Technology

[0002] In recent years, nanomaterials have attracted widespread attention from researchers due to their immense scientific value and potential applications. Theoretical and experimental studies have shown that nanomaterials exhibit superior performance compared to bulk materials; in particular, one-dimensional nanomaterials such as nanowires and nanotubes, possessing one-dimensional electron transport channels, demonstrate superior electrochemical performance compared to ordinary bulk materials. Cathode materials with intercalation reactions dominate zinc-ion batteries (ZIBs), among which layered vanadium compounds show promise as cathode materials based on intercalation reactions for ZIBs.

[0003] Vanadium oxide hydrate belongs to the family of layered vanadium compounds. Since H2V3O8 better describes the crystal structure of water molecules, it is used instead of V3O7 hydrate. H2V3O8 consists of hydrogen-bonded layers of V3O8, each layer composed of VO6 octahedra and VO5 triangular bipyramids. The VO6 octahedra share edges with adjacent octahedra stacked along the c-axis and corners with the VO5 triangular bipyramids sharing the edges, forming a layer parallel to the (100) plane. Furthermore, hydrogen atoms bond with oxygen atoms labeled O(6) within the VO6 octahedra to form hydrogen bonds and maintain the V3O8 layers, resulting in a three-dimensional structure (Y. Oka, T. Yao, N. Yamamoto, J. Solid State Chem. 1990, 89, 372). Also, H2V3O8 is a V 4+ / V 5+ The intermediate phase with a ratio of 1 / 2 and a higher valence (V) of 4.67 exhibits a larger theoretical capacity and better resistance to air oxidation than the substable VO2(B). Compared to V2O5, H2V3O8 has a higher valence due to its higher valence (V). 4+ / V 5+ The mixed valence states result in higher electronic conductivity (H.Li, T.Zhai, P.He, Y.Wang, E.Hosono, H.Zhou, J.Mater.Chem. 2011, 21, 1780). The weak hydrogen bonds between the V3O8 layers are thought to facilitate reversible insertion / extraction of ions (Q.An, J.Sheng, X.Xu, Q.Wei, Y.Zhu, C.Han, C.Niu, L.Mai, New J.Chem. 2014, 38, 2075).

[0004] In recent years, researchers have successfully prepared one-dimensional H₂V₃O₈ nanostructures using various methods, which have indeed improved their electrochemical kinetics. However, achieving long-term cycling stability during the subsequent rapid zinc ion insertion-extraction process remains a significant challenge. Therefore, the development of H₂V₃O₈ nanowires with improved rate performance and cycling stability is of great importance as an aqueous zinc ion cathode material. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing an ultra-long H2V3O8 nanowire, its preparation method, and its application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing ultralong H2V3O8 nanowires, comprising the following steps:

[0008] 1) Mix the vanadium source, reducing agent, and solvent to obtain a solution;

[0009] 2) After the solution undergoes a hydrothermal reaction, it is washed and dried sequentially to obtain ultralong H2V3O8 nanowires;

[0010] The reducing agent in step 1) is one or more of oxalic acid, citric acid, ascorbic acid, and malic acid.

[0011] Preferably, the vanadium source in step 1) is one or more of vanadium pentoxide, ammonium metavanadate, vanadium dioxide, and sodium metavanadate.

[0012] Preferably, the molar ratio of vanadium source to reducing agent in step 1) is 1 to 6:1; the mass-volume ratio of vanadium source to solvent is 0.1 to 0.8 g: 30 to 50 mL.

[0013] Preferably, the solvent in step 1) is a mixture of an organic solvent and water or water; the organic solvent is one or more of alcohol, N,N-dimethylformamide, ethylene glycol and glycerol.

[0014] Preferably, step 1) involves ultrasonically mixing a vanadium source and a solvent to obtain a mixed solution, which is then mixed with a reducing agent.

[0015] The ultrasonic mixing power is 300–700W, and the ultrasonic mixing time is 30–45 minutes.

[0016] Preferably, after the mixing in step 1) is completed, the pH value of the solution is adjusted to 1-3.

[0017] Preferably, the temperature of the hydrothermal reaction in step 2) is 180–220°C, and the reaction time is 24–48 h.

[0018] Preferably, the washing reagent in step 2) is water and anhydrous ethanol; the drying temperature is 50-70°C and the drying time is 8-15 hours.

[0019] The present invention also provides ultralong H2V3O8 nanowires prepared by the aforementioned preparation method.

[0020] This invention also provides the application of the aforementioned ultralong H2V3O8 nanowires in aqueous zinc ion cathode materials.

[0021] The beneficial effects of this invention include:

[0022] 1) The preparation method of the ultra-long H2V3O8 nanowires of the present invention has the advantages of simple preparation process, low energy consumption, short time cycle, easy process control, and high purity of the obtained product.

[0023] 2) The aqueous zinc ion ultra-long H2V3O8 nanowire cathode material has good rate performance, which can meet the requirements of large capacity, achieve fast charge and discharge, and has good cycle stability. Attached Figure Description

[0024] Figure 1 The XRD pattern of the ultralong H2V3O8 nanowires in Example 1;

[0025] Figure 2 This is a scanning electron microscope image of the ultralong H2V3O8 nanowires from Example 1;

[0026] Figure 3 The constant current charge-discharge curves of the ultra-long H2V3O8 nanowire assembled battery in Example 1 at different current densities are shown.

[0027] Figure 4 The cycling performance curve of the ultra-long H2V3O8 nanowire assembled battery in Example 1;

[0028] Figure 5 The cycling performance of the ultralong H2V3O8 nanowire-assembled battery in Example 1 at a current density of 0.1 A / g is shown.

[0029] Figure 6 The cycling performance of the ultralong H2V3O8 nanowire assembled battery in Example 1 at a current density of 5 A / g is shown. Detailed Implementation

[0030] This invention provides a method for preparing ultralong H2V3O8 nanowires, comprising the following steps:

[0031] 1) Mix the vanadium source, reducing agent, and solvent to obtain a solution;

[0032] 2) After the solution undergoes a hydrothermal reaction, it is washed and dried sequentially to obtain ultralong H2V3O8 nanowires;

[0033] The reducing agent in step 1) is one or more of oxalic acid, citric acid, ascorbic acid, and malic acid.

[0034] In this invention, the vanadium source in step 1) is preferably one or more of vanadium pentoxide, ammonium metavanadate, vanadium dioxide, and sodium metavanadate.

[0035] In this invention, the molar ratio of vanadium source to reducing agent in step 1) is preferably 1-6:1, more preferably 2-5:1; the mass-volume ratio of vanadium source to solvent is preferably 0.1-0.8g:30-50mL, more preferably 0.2-0.7g:35-45mL, and more preferably 0.3-0.6g:37-40mL.

[0036] In this invention, the solvent in step 1) is preferably a mixture of an organic solvent and water or water; the organic solvent is preferably one or more of alcohol, N,N-dimethylformamide, ethylene glycol and glycerol.

[0037] In this invention, the mixing in step 1) is preferably performed by ultrasonic mixing of a vanadium source and a solvent to obtain a mixed solution, which is then mixed with a reducing agent.

[0038] The ultrasonic mixing power is preferably 300-700W, more preferably 350-600W, and even more preferably 400-500W; the ultrasonic mixing time is preferably 30-45min, and even more preferably 35-40min.

[0039] In this invention, after the mixing is completed in step 1), the pH value of the solution is adjusted. The pH value of the solution is preferably adjusted to 1 to 3, and more preferably to 2.

[0040] In this invention, the temperature of the hydrothermal reaction in step 2) is preferably 180-220°C, more preferably 190-210°C, and even more preferably 200°C; the time of the hydrothermal reaction is preferably 24-48h, more preferably 28-42h, and even more preferably 30-36h.

[0041] In this invention, the washing reagent in step 2) is preferably water and anhydrous ethanol; the drying temperature is preferably 50-70°C, more preferably 55-65°C, and even more preferably 60°C; the drying time is preferably 8-15 hours, more preferably 10-13 hours, and even more preferably 11-12 hours.

[0042] The present invention also provides ultralong H2V3O8 nanowires prepared by the aforementioned preparation method.

[0043] This invention also provides the application of the aforementioned ultralong H2V3O8 nanowires in aqueous zinc ion cathode materials.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] 0.524 g of vanadium pentoxide was placed in a beaker, and 40 mL of pure water was added. The mixture was ultrasonically mixed at 500 W for 30 min to disperse it evenly and form an orange-yellow solution. Then, 0.1443 g of oxalic acid dihydrate was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 1 using 2 mol / L hydrochloric acid. The well-mixed solution was placed in a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and hydrothermally reacted at 220 °C for 36 h. After the hydrothermal reaction was completed, the mixture was allowed to cool naturally to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 60 °C for 12 h to obtain ultralong H₂V₃O₈ nanowires.

[0047] The XRD pattern of the ultralong H2V3O8 nanowires in Example 1 was determined using a Brucker D8 Advance X-ray diffractometer. The XRD pattern is shown below. Figure 1 As shown. By Figure 1 It can be seen that the X-ray diffraction data of the ultra-long H2V3O8 nanowires in Example 1 are in good agreement with the JCPDS standard card (card number: 85-2401) of H2V3O8, and the obvious diffraction peaks indicate that the prepared H2V3O8 nanowires have good crystallinity.

[0048] The scanning electron microscope image of the ultralong H2V3O8 nanowire in Example 1 is shown below. Figure 2 As shown. By Figure 2 It can be seen that the morphology of the ultra-long H2V3O8 nanowires in Example 1 is that the nanowires are grown parallel to the substrate, with lengths concentrated in the range of 20 to 80 μm and diameters in the range of 70 to 300 nm.

[0049] In Example 1, ultralong H₂V₃O₈ nanowires were used to fabricate a positive electrode sheet with an acetylene black and PVDF mass ratio of 7:1.5:1.5. A button cell was then assembled using a 3 mol / L ZnSO₄ aqueous solution as the electrolyte. Constant current charge-discharge tests were conducted at different current densities within a voltage range of 0.3–1.4 V. The rate performance of the H₂V₃O₈ electrode was tested at a series of current densities ranging from 0.2 to 10 A / g. The constant current charge-discharge curves at different current densities are shown below. Figure 3 As shown, the cycle performance curve is as follows: Figure 4 As shown. By Figure 4It can be seen that even at an extremely high current density of 10 A / g, the capacity can still reach 159.7 mAh / g; when the current density increases from 0.2 A / g to 10 A / g and then decreases back to 0.2 A / g, the discharge capacity recovers to 354.5 mAh / g, with a recovery rate of 76.3%. The cycle performance of the battery assembled from the ultralong H2V3O8 nanowires in Example 1 at current densities of 0.1 A / g and 5 A / g is as follows. Figure 5 , Figure 6 As shown, at a current density of 0.1 A / g, the sample exhibits a specific capacity as high as 306.7 mAh / g, and the discharge specific capacity remains at 220.1 mAh / g after 50 cycles, with a capacity retention of 78.3% (the ratio of the discharge specific capacity of 220.1 mAh / g after 50 cycles to the initial specific capacity of 281.2 mAh / g). At a current density of 5 A / g, the sample exhibits a specific capacity as high as 133.1 mA h / g, and the discharge specific capacity remains at 84 mAh / g after 50 cycles, with a capacity retention of 90.13% (the ratio of the discharge specific capacity of 84 mAh / g after 50 cycles to the initial specific capacity of 93.2 mAh / g).

[0050] The Zn / / H2V3O8 battery of the present invention has good rate performance, which can meet the requirements of large capacity and achieve fast charging and discharging.

[0051] Example 2

[0052] 0.262 g of vanadium pentoxide was placed in a beaker, and 35 mL of a mixture of pure water and alcohol (volume ratio of pure water to alcohol: 1:1, alcohol concentration: 50%) was added. The mixture was ultrasonically mixed at 400 W for 40 min to disperse it evenly and form an orange-yellow solution. Then, 0.072 g of oxalic acid dihydrate was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 1 using 2 mol / L hydrochloric acid. The homogeneous solution was placed in a 100 mL hydrothermal reactor lined with polytetrafluoroethylene (PTFE) and hydrothermally reacted at 180 °C for 36 h. After the hydrothermal reaction was complete, the mixture was allowed to cool naturally to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 55 °C for 13 h to obtain ultralong H₂V₃O₈ nanowires.

[0053] Example 3

[0054] 0.524 g of vanadium pentoxide was placed in a beaker, and 45 mL of a mixture of pure water and alcohol (volume ratio of pure water to alcohol: 1:1, alcohol concentration: 50%) was added. The mixture was ultrasonically mixed at 600 W for 35 min to disperse it evenly and form an orange-yellow solution. Then, 0.1443 g of citric acid was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 2 using 2 mol / L hydrochloric acid. The well-mixed solution was placed in a 100 mL hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 220 °C for 24 h. After the hydrothermal reaction was completed, the mixture was allowed to cool naturally to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 65 °C for 10 h to obtain ultralong H₂V₃O₈ nanowires.

[0055] Example 4

[0056] 0.6288 g of ammonium metavanadate was placed in a beaker, and 40 mL of pure water was added. The mixture was ultrasonically mixed at 500 W for 30 min to disperse it evenly and form an orange-yellow solution. Then, 0.1732 g of oxalic acid dihydrate was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 1 using 2 mol / L hydrochloric acid. The well-mixed solution was placed in a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and hydrothermally reacted at 200 °C for 48 h. After the hydrothermal reaction was completed, the mixture was allowed to cool naturally to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 60 °C for 12 h to obtain ultralong H₂V₃O₈ nanowires.

[0057] Example 5

[0058] 0.4718 g of ammonium metavanadate was placed in a beaker, and 40 mL of a mixture of pure water and ethylene glycol (volume ratio of pure water to ethylene glycol: 1:1) was added. The mixture was ultrasonically mixed at 500 W for 30 min to disperse it evenly and form an orange-yellow solution. Then, 0.101 g of oxalic acid dihydrate was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 3 using 2 mol / L hydrochloric acid. The well-mixed solution was placed in a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and hydrothermally reacted at 220 °C for 36 h. After the hydrothermal reaction was completed, the mixture was allowed to cool naturally to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 60 °C for 12 h to obtain ultralong H₂V₃O₈ nanowires.

[0059] Example 6

[0060] 0.4718 g of sodium metavanadate was placed in a beaker, and 40 mL of a mixture of pure water and N,N-dimethylformamide (volume ratio of pure water to N,N-dimethylformamide was 1:1) was added. The mixture was ultrasonically mixed at 500 W for 30 min to disperse it evenly and form an orange-yellow solution. Then, 0.213 g of ascorbic acid was added to the solution, and the mixture was stirred at 25 rpm for 10 min. The pH of the solution was adjusted to 2 using 2 mol / L hydrochloric acid. The well-mixed solution was placed in a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and hydrothermally reacted at 200 °C for 36 h. After the hydrothermal reaction was completed, the mixture was naturally cooled to room temperature. The cooled product was washed sequentially with pure water and anhydrous ethanol, and then dried at 60 °C for 12 h to obtain ultralong H2V3O8 nanowires.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of ultralong H2V3O8 nanowires in aqueous zinc-ion cathode materials, characterized in that, The preparation method of ultralong H2V3O8 nanowires includes the following steps: 1) Mix the vanadium source, reducing agent, and solvent to obtain a solution; 2) After the solution undergoes a hydrothermal reaction, it is washed and dried sequentially to obtain ultralong H2V3O8 nanowires; Step 1) The reducing agent is one or more of citric acid, ascorbic acid, and malic acid; Step 1) The molar ratio of vanadium source to reducing agent is 1~6:1; the mass-volume ratio of vanadium source to solvent is 0.1~0.8g:30~50mL; Step 1) After mixing is completed, adjust the pH value of the solution to 1-3; The temperature of the hydrothermal reaction in step 2) is 200~220℃.

2. The application according to claim 1, characterized in that, Step 1) The vanadium source is one or more of vanadium pentoxide, ammonium metavanadate, and sodium metavanadate.

3. The application according to claim 2, characterized in that, Step 1) The solvent is a mixture of an organic solvent and water or water; the organic solvent is one or more of alcohol, N,N-dimethylformamide, ethylene glycol and glycerol.

4. The application according to claim 2, characterized in that, Step 1) The mixing involves ultrasonically mixing a vanadium source and a solvent to obtain a mixed solution, which is then mixed with a reducing agent. The ultrasonic mixing power is 300~700W, and the ultrasonic mixing time is 30~45min.

5. The application according to claim 3 or 4, characterized in that, The hydrothermal reaction time in step 2) is 24~48h.

6. The application according to claim 5, characterized in that, Step 2) The washing reagents are water and anhydrous ethanol; the drying temperature is 50~70℃ and the drying time is 8~15h.

Images