A method for mass production of sodium polyvanadate nanowire spheres

Abstract

This invention discloses a method for the mass production of sodium polyvanadate nanowires. The method includes: adding a sodium vanadium extraction leachate to an inorganic acid to hydrolyze and precipitate vanadium, obtaining a hydrated sodium polyvanadate nanowire dispersion; obtaining hydrated sodium polyvanadate nanowires by vacuum filtration or pressure filtration of the hydrated sodium polyvanadate nanowire dispersion; and drying and high-temperature annealing the hydrated sodium polyvanadate nanowires to obtain sodium vanadium oxide nanowires. This nanofiberization process is rapid, simple, and operates under mild conditions. It allows for scalable containers, uses inexpensive and environmentally friendly dispersant (industrial water), and is suitable for large-scale production under conditions such as mechanical stirring and normal pressure. This technology breaks through the conventional thinking of ordinary technicians, overcomes the technical prejudices of traditional nanomaterial preparation, especially sodium polyvanadate nanowires, overcomes the shortcomings of existing hydrothermal synthesis or preparation techniques, solves long-standing technical problems, and achieves unexpected results.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation technology, and in particular to a method for mass production of sodium polyvanadate nanowire spheres. Background Technology

[0002] Layered sodium polyvanadate nanofibers (or sodium ion-stabilized vanadium oxide nanowires, such as Na₂V₆O₃) are one-dimensional materials. 16 NaV3O8, NaV6O 15 / Na 0.33 V2O5 has unique applications in electrochemical energy storage (such as zinc-ion batteries, sodium-ion batteries, lithium-ion batteries, and supercapacitors) and catalysts (such as fixed-bed and fluidized-bed reactors) due to its large specific surface area, large interlayer spacing, numerous active sites, short ion / electron diffusion transport distance, and good mechanical flexibility.

[0003] Currently, the synthesis of layered sodium polyvanadate nanofibers is mainly limited to hydrothermal methods. These methods are demanding (high temperature and high pressure, generally above 180°C), have long reaction times (generally over ten hours), and may require surfactants and other additives, making large-scale production difficult. Low-temperature or room-temperature sol-gel techniques also exist, but these methods are time-consuming (several days), use expensive raw materials (generally V₂O₅), have lengthy process flows, and may include freeze-drying steps. Furthermore, the fibers tend to aggregate into bundles, making them unsuitable for low-cost industrial production. For electrochemical energy storage or electrode materials, compared to solid bulk materials, nanowire structures are more advantageous in shortening diffusion paths and electrolyte diffusion, while avoiding / mitigating structural damage and material failure caused by volume changes during charging and discharging. For catalysts, spherical catalysts avoid the granulation process, and nanowire spherical structures are more conducive to improving catalytic performance.

[0004] Therefore, how to achieve low-cost, rapid, large-scale, and green preparation technology for sodium polyvanadate nanowires has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the mass production of sodium polyvanadate nanowires, which can achieve low-cost, rapid, large-scale, and green production of sodium polyvanadate nanowires.

[0006] To achieve the above objectives, the present invention provides a method for mass production of sodium polyvanadate nanowire spheres, the method comprising:

[0007] The sodium vanadium extraction leachate was added to an inorganic acid and vanadium was hydrolyzed and precipitated to obtain a hydrated sodium polyvanadate nanowire dispersion.

[0008] The hydrated sodium polyvanadate nanowire dispersion was obtained by vacuum filtration or pressure filtration.

[0009] The hydrated sodium polyvanadate nanowires were dried and annealed at high temperature to obtain sodium vanadium oxide nanowires.

[0010] Optionally, the conditions for vanadium hydrolysis precipitation include: a V concentration of 5-15 g / L, a pH value of 1.7-4.0, a temperature of 80-100℃, a stirring rate of 100-800 rpm, and a reaction time of 1-4 h.

[0011] Optionally, the inorganic acid is one or more of the following: hydrochloric acid, sulfuric acid, and nitric acid.

[0012] Optionally, the sodium vanadium extraction leachate is a solution obtained by diluting industrial-grade sodium vanadium extraction leachate, wherein the vanadium content in the industrial-grade sodium vanadium extraction leachate is 40-60 g / L.

[0013] Optionally, the size of the hydrated sodium polyvanadate nanowire spheres is 0.5-2 mm.

[0014] Optionally, the sodium polyvanadate nanofibers in the hydrated sodium polyvanadate nanowire spheres have a diameter of 20-2000 nm.

[0015] Optionally, the high-temperature annealing conditions include: an annealing temperature of 300-600℃ and an annealing time of 0.5-2h.

[0016] Optionally, the sodium vanadium extraction leachate includes: obtaining the sodium vanadium extraction leachate based on the sodium roasting-water leaching method of vanadium slag.

[0017] This invention also provides the application of sodium polyvanadate nanowires in catalysts.

[0018] This invention also provides an application of sodium polyvanadate nanowires in battery materials.

[0019] The technical effects and advantages of this invention are as follows:

[0020] This invention provides a method for mass production of sodium polyvanadate nanowires, the method comprising: adding a sodium vanadium extraction leachate to an inorganic acid to hydrolyze and precipitate vanadium to obtain a hydrated sodium polyvanadate nanowire dispersion; obtaining hydrated sodium polyvanadate nanowires by vacuum filtration or pressure filtration of the hydrated sodium polyvanadate nanowire dispersion; and drying and high-temperature annealing the hydrated sodium polyvanadate nanowires to obtain sodium vanadium oxide nanowires.

[0021] This nanofiberization process is rapid, simple, and operates under mild conditions. It allows for scalable containers, utilizes inexpensive and environmentally friendly dispersants (industrial water), and is suitable for large-scale production under conditions such as mechanical stirring and atmospheric pressure. This technology breaks through the conventional thinking of ordinary technicians, overcomes the technical biases of traditional nanomaterial preparation methods, especially sodium polyvanadate nanowires, overcomes the shortcomings of existing hydrothermal synthesis or preparation techniques, solves long-standing technical problems, and achieves unexpected results.

[0022] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0023] Figure 1 Flowchart of a method for mass production of sodium polyvanadate nanowires;

[0024] Figure 2 Optical digital photograph of hydrated sodium polyvanadate nanowire spheres;

[0025] Figure 3 XRD pattern of hydrated sodium polyvanadate nanowire spheres;

[0026] Figure 4 SEM image (ad) and EDX spectrum (e) of hydrated sodium polyvanadate nanowire spheres;

[0027] Figure 5 Optical digital photograph of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (500℃, 2h, air atmosphere);

[0028] Figure 6 XRD powder diffraction pattern of highly crystalline sodium polyvanadate nanowires obtained by annealing hydrated sodium polyvanadate nanowires;

[0029] Figure 7 Surface microstructure of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (ad represents different magnifications, ×60, ×300, ×1000, ×3000).

[0030] Figure 8 Cross-sectional microstructure of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (ad represents different magnifications, ×100, ×3000, ×10000, d is a schematic diagram of the multi-level structure of the nanowire spheres).

[0031] Figure 9EDX spectrum of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (where a is the overall sampling point, c is the local sampling point; b and d correspond to a and c, respectively). Detailed Implementation

[0032] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Furthermore, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0034] To address the shortcomings of existing technologies, this invention discloses a method for mass production of sodium polyvanadate nanowire spheres, such as... Figure 1 As shown. The method includes the following steps:

[0035] 1. A certain concentration of sodium vanadium extraction leachate was added to an inorganic acid to hydrolyze and precipitate vanadium, thereby obtaining a dispersion of hydrated sodium polyvanadate nanowires.

[0036] Specifically, this involves adding a sodium-based vanadium extraction leachate of a specific concentration (mainly sodium metavanadate, NaVO3) to an inorganic acid at a certain stirring rate, and obtaining hydrated sodium polyvanadate (Na2V6O3) through hydrolysis and precipitation of vanadium. 16 Nanowire sphere dispersion (locally confined rapid ion exchange, crystal orientation growth).

[0037] The conditions for vanadium hydrolysis precipitation include: a V concentration of 5-15 g / L, preferably 8-12 g / L; a pH value of 1.7-4.0, preferably 2.0-3.5; a temperature of 80-100℃, preferably 90-98℃; a stirring rate of 100-800 rpm, preferably 400-600 rpm; and a reaction time of 1-4 h, preferably 2-3 h.

[0038] It should be noted that, in order to reduce production costs, the vanadium source of this invention can be industrial-grade sodium vanadium extraction leaching solution (qualified solution with a vanadium content of 40-60 g / L), and is not limited to the water leaching solution (qualified solution) obtained by sodium roasting-water leaching of vanadium slag. Other vanadium sources known in the art can also be used.

[0039] It should also be noted that the water refers to industrial or domestic water or purified water; the acid refers to one or a combination of hydrochloric acid, sulfuric acid, and nitric acid.

[0040] 2. The hydrated sodium polyvanadate nanowire dispersion is obtained by vacuum filtration or pressure filtration.

[0041] The size of the hydrated sodium polyvanadate nanowire spheres ranges from 0.5 to 2 mm, while the diameter of the sodium polyvanadate nanofibers ranges from 20 to 2000 nm.

[0042] It should also be noted that the hydrated sodium polyvanadate nanowires are brick red.

[0043] 3. The hydrated sodium polyvanadate nanowires are dried and annealed at high temperature to obtain sodium vanadium oxide nanowires (i.e., highly crystalline sodium polyvanadate nanowires).

[0044] Specifically, this includes obtaining brownish-red sodium vanadium oxide (NaV3O8) nanowire spheres through washing, drying, and high-temperature annealing.

[0045] The high-temperature annealing conditions include: an annealing temperature of 300-600℃ and an annealing time of 0.5-2h.

[0046] To better explain this solution, embodiments are also provided below.

[0047] Example 1

[0048] A method for mass production of sodium polyvanadate nanowire spheres, comprising the following steps:

[0049] (1) Weigh a certain amount of sulfuric acid (volume concentration 50%) and add the diluted sodium vanadium extraction leachate (V concentration 10g / L) while stirring. Control the pH value to 2.1 and stir at 500rpm for 5 minutes at room temperature.

[0050] (2) Heat the microsuspension obtained in step (1) and keep it at 96°C for 2 hours.

[0051] (3) The hydrolyzed vanadium dispersion (hydrated sodium polyvanadate nanowire dispersion) obtained in step (2) was filtered to obtain brick-red hydrated sodium polyvanadate nanowires, and then dried.

[0052] It should be noted that this invention also includes research and analysis on hydrated sodium polyvanadate nanowire spheres, such as... Figure 2This is an optical digital photograph of hydrated sodium polyvanadate nanowire spheres. It can be seen that the particles are uniform, with individual spheres measuring sub-millimeter in size, and they are easily dispersed into spherical powder.

[0053] Figure 3 The image shows the XRD pattern of hydrated sodium polyvanadate nanowire spheres. Analysis reveals that it is Na₂V₆O. 16 (PDF card number 22-1412), XRD analysis shows it to be Na2V6O. 16 (PDF card number 22-1412), which is also consistent with the results reported by hydrothermal or sol-gel methods (Nano Lett. 2018, 18, 2402-2410; Batteries & Supercaps 2020, 3, 254-260; Cryst. Growth Des., 2005, 5, 969-974; Inorg. Chem. 2012, 51, 2241-2246; J. Am. Chem. Soc., 2004, 126, 3422-3423; Adv. Energy Mater. 2020, 10, 2001595; J. Mater. Chem., 2012, 22, 2560-2565; Nat. Commun., 2018, 9, 1656).

[0054] Figure 4 The images show SEM images (ad) and EDX spectra (e) of hydrated sodium polyvanadate nanowire spheres. It can be seen that the submillimeter particles of the sodium polyvanadate nanowire spheres are composed of nanofibers, and elemental analysis reveals that they mainly contain V, O, and Na (the test used a carbon conductive adhesive / aluminum alloy substrate, sputtered with gold); the V, O, and Na originate from Na₂V₆O. 16 The trace sulfur (S) originated from unwashed Na₂SO₄. This indicates that the hydrated sodium polyvanadate (Na₂V₆O₂)... 16 Nanofibers with a width of less than 50 nm exhibit oriented bundle formation.

[0055] (4) The hydrated sodium polyvanadate nanowires obtained in step (3) were placed in a calcining furnace and heat-treated at 500°C for 2 hours to obtain brownish-red sodium vanadium oxide nanowires (i.e., highly crystalline sodium polyvanadate nanowires), with the main component being NaV3O8 and a small amount of NaV6O. 15 .

[0056] It should be noted that this invention also analyzes and studies sodium vanadium oxide nanowire spheres, such as... Figure 5Optical digital photographs of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (500℃, 2h, air atmosphere). It can be seen that the product has uniform particle size, with individual spheres measuring sub-millimeter in size, virtually no shrinkage, and is easily dispersed into spherical powder under external force.

[0057] Figure 6 XRD powder diffraction pattern of highly crystalline sodium polyvanadate nanowires obtained by annealing hydrated sodium polyvanadate nanowires (500℃ air annealing for 2h, main component NaV3O8, PDF card number 28-1171; small amount of NaV6O) 15 (PDF card number 28-1172). Comparison of XRD powder diffraction patterns shows that this hydrated sodium polyvanadate (Na₂V₆O₂) 16 The main component of the annealed nanofibers is monoclinic NaV3O8 crystal phase (PDF card number 28-1171), accompanied by a small amount of NaV6O. 15 Or Na 0.33 V2O5 phase (PDF card number 28-1172). The phase of this NaV3O8 nanofiber is consistent with the phase of products obtained by hydrothermal or other solid-state calcination reactions (J. Mater. Chem. A, 2015, 3, 3044-3050; Adv. Energy Mater. 2018, 8, 1702463).

[0058] Figure 7 Surface microstructure of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (ad represents different magnifications, ×60, ×300, ×1000, ×3000) (annealed in air at 500℃ for 2h, main component NaV3O8, PDF card number 28-1171; small amount of NaV6O) 15 (PDF card number 28-1172). The individual microspheres in the sample are sub-millimeter quasi-spherical particles with bulging protrusions on the surface, and the surface is composed entirely of nanofibers. It was also found that higher temperature and longer annealing time resulted in better fiber crystallinity, more pronounced angular shapes of fiber crystals, and the formation of single crystals from fiber bundles, which increased the diameter.

[0059] Figure 8 The obtained hydrated sodium polyvanadate (Na2V6O) 16Microscopic morphology of highly crystalline sodium polyvanadate (NaV3O8) nanowire spheres obtained by annealing nanowire spheres (500℃ air annealing for 2h) (ac shows the SEM morphology of broken nanowire spheres and their interior; d shows a schematic diagram of the nanowire sphere structure, where the fibers are nanowires, the outer spheres are nanowire microspheres of about 0.5 mm in size, and the inner spheres are microspheres composed of nanowires of about 0.05 mm in size). The broken sodium polyvanadate nanowire spheres show a consistent internal and external structure, both being nanowire structures. Interestingly, smaller self-assembled nanowire spheres (about 0.05 mm) still exist inside the spheres, representing a multi-level self-assembly structure (i.e., nanowires assemble into microspheres, microspheres assemble into millimeter spheres, and millimeter spheres loosely aggregate into clumps). This structure with internal nanowire microspheres is also consistent with... Figure 7 The bulging phenomenon on the surface of the submillimeter microspheres is consistent with this.

[0060] Figure 9 EDX spectrum of highly crystalline sodium polyvanadate nanowire spheres obtained by annealing hydrated sodium polyvanadate nanowire spheres (air annealing at 500℃ for 2 hours). It can be seen that the product contains elements such as V, Na, and O, and the composition remains basically the same before and after calcination.

[0061] Example 2

[0062] A method for mass production of sodium polyvanadate nanowire spheres, comprising the following steps:

[0063] (1) Weigh a certain amount of sulfuric acid (volume concentration 20%) and add an appropriate amount of diluted sodium vanadium extraction leaching solution (V concentration 15g / L) while stirring. Control the pH value to 3.0 and stir at room temperature for 5 minutes at 500 rpm.

[0064] (2) Heat the suspension obtained in step (1) and keep it at 80°C for 4 hours.

[0065] (3) The hydrolyzed vanadium precipitate solid obtained in step (2) is filtered to obtain hydrated sodium polyvanadate nanowire spheres, which are then washed and dried.

[0066] (4) The sodium polyvanadate nanowire aggregates obtained in step (3) are placed in a calcining furnace and heat-treated at 500°C for 1 hour to obtain highly crystalline sodium polyvanadate nanowire aggregates.

[0067] Example 3

[0068] A method for mass production of sodium polyvanadate nanowire spheres, comprising the following steps:

[0069] (1) Weigh a certain amount of sulfuric acid (volume concentration 50%) and add diluted sodium vanadium extraction leachate (V concentration 15g / L) while stirring. Control the pH value to 3.0 and stir at 500rpm for 5 minutes at room temperature. Flow into the storage tank.

[0070] (2) Flow the suspension from the storage tank in step (1) into a 20-50m... 3 Heat in a fiberglass or enamel-lined, PTFE-lined reactor (tank) and keep at 90℃ for 2 hours.

[0071] (3) The hydrolyzed vanadium dispersion obtained in step (2) was filtered to obtain sodium polyvanadate nanowire aggregates, which were then washed and dried.

[0072] (4) The sodium polyvanadate nanowire aggregates obtained in step (3) are placed in a calcining furnace and heat-treated at 400°C for 1 hour to obtain highly crystalline sodium polyvanadate nanowire aggregates.

[0073] This invention provides a method for mass production of sodium polyvanadate nanowires, the method comprising: adding a sodium vanadium extraction leachate to an inorganic acid to hydrolyze and precipitate vanadium to obtain a hydrated sodium polyvanadate nanowire dispersion; obtaining hydrated sodium polyvanadate nanowires by vacuum filtration or pressure filtration of the hydrated sodium polyvanadate nanowire dispersion; and drying and high-temperature annealing the hydrated sodium polyvanadate nanowires to obtain sodium vanadium oxide nanowires.

[0074] This nanofiberization process is rapid, simple, and operates under mild conditions. It allows for scalable containers, utilizes inexpensive and environmentally friendly dispersants (industrial water), and is suitable for large-scale production under conditions such as mechanical stirring and atmospheric pressure. This technology breaks through the conventional thinking of ordinary technicians, overcomes the technical biases of traditional nanomaterial preparation methods, especially sodium polyvanadate nanowires, overcomes the shortcomings of existing hydrothermal synthesis or preparation techniques, solves long-standing technical problems, and achieves unexpected results.

[0075] The present invention also provides sodium polyvanadate nanowire spheres.

[0076] This invention also provides an application of sodium polyvanadate nanowires in battery materials.

[0077] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for mass production of sodium polyvanadate nanowire spheres, characterized in that, The method includes: The sodium vanadium extraction leachate was added to an inorganic acid and vanadium was hydrolyzed and precipitated to obtain a hydrated sodium polyvanadate nanowire dispersion. The hydrated sodium polyvanadate nanowire dispersion was obtained by vacuum filtration or pressure filtration. The hydrated sodium polyvanadate nanowires were dried and annealed at high temperature to obtain sodium vanadium oxide nanowires. The conditions for vanadium hydrolysis precipitation include: V concentration of 5-15 g / L, pH value of 1.7-4.0, temperature of 80-100℃, stirring rate of 100-800 rpm, and reaction time of 1-4 h. The size of the hydrated sodium polyvanadate nanowire spheres is 0.5-2 mm; The sodium polyvanadate nanofibers in the hydrated sodium polyvanadate nanospheres have a diameter of 20-2000 nm.

2. The method for mass production of sodium polyvanadate nanowires according to claim 1, characterized in that, The inorganic acid is one or more of the following: hydrochloric acid, sulfuric acid, and nitric acid.

3. The method for mass production of sodium polyvanadate nanowires according to claim 1, characterized in that, The sodium vanadium extraction leachate is a solution obtained by diluting industrial-grade sodium vanadium extraction leachate, wherein the vanadium content in the industrial-grade sodium vanadium extraction leachate is 40-60 g / L.

4. The method for mass production of sodium polyvanadate nanowires according to claim 1, characterized in that, The high-temperature annealing conditions include: an annealing temperature of 300-600℃ and an annealing time of 0.5-2h.

5. The method for mass production of sodium polyvanadate nanowires according to claim 1, characterized in that, The sodium vanadium extraction leachate comprises: the sodium vanadium extraction leachate obtained by sodium roasting-water leaching of vanadium slag.

6. Application of sodium polyvanadate nanowires prepared according to any one of claims 1-5 in catalyst materials.

7. Application of sodium polyvanadate nanowires prepared according to any one of claims 1-5 in battery materials.

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