Method for manufacturing vanadium sodium phosphate nanomaterials

Abstract

This invention relates to a method for producing vanadium sodium phosphate nanomaterials, comprising the steps of: 1) weighing out raw materials consisting of tetravalent vanadium, sodium phosphate, and sodium fluoride, or raw materials consisting of tetravalent vanadium and sodium phosphate; and 2) feeding the raw materials into a high-speed homogenization polishing machine to complete a rapid nucleation process and a crystallization growth control process. This invention combines the principles of atomic economy to efficiently produce nano-sized vanadium sodium phosphate using a high-power, high-speed polishing device; achieves efficient utilization of raw material atoms, eliminates the generation of excess waste and waste of raw materials, and eliminates solvent discharge and wastewater treatment processes from the washing process, thus achieving environmentally friendly manufacturing; achieves high-speed collision and reaction acceleration with a high-power, high-speed polishing device, effectively controls the particle size of the product, and enables the production of nano-sized products; and has advantages such as being easy to operate, highly efficient, and easy to scale up industrially, contributing to the advancement of research, dissemination, and application of vanadium sodium phosphate materials in the field of electrochemical energy storage.

Description

[Technical Field]

[0001] The present invention relates to the technical field of electrode material manufacturing, and more particularly to a method for manufacturing vanadium sodium phosphate nanomaterials used as electrode materials for alkali metal secondary batteries such as lithium, sodium, and potassium. [Background technology]

[0002] Sodium vanadium phosphate is an ideal electrode material for sodium-ion secondary batteries due to its excellent sodium ion transport efficiency as a sodium ion superconductor. Conventional methods for producing sodium vanadium phosphate mainly involve high-temperature solid-phase synthesis and sol-gel methods. However, sodium vanadium phosphate produced by these methods has a non-uniform particle size distribution, long production times, and high energy consumption due to high temperatures, which severely limits the development of scale-up production.

[0003] In recent years, efficient methods for producing sodium vanadium phosphate using hydrothermal and solvothermal synthesis have attracted attention. Examples include "Method for producing sodium vanadium fluorophosphate" disclosed in Chinese patent application No. CN105762355A, "Method for producing and use of sodium vanadium fluorophosphate" disclosed in Chinese patent application No. CN105762356A, and "Sodium vanadium fluorophosphate and its production method and use" disclosed in Chinese patent application No. CN107154493A. Liquid-phase reactions can avoid problems such as high energy consumption and non-uniform particle size distribution of the product, but the large particle size results in low electronic conductivity, which negatively affects the sodium storage performance of the product. To address this problem, researchers have proposed using methods such as ion exchange (for example, "Method for producing vanadium sodium phosphate material" disclosed in Chinese patent application No. CN114572957A, and "Method for producing nano-sized vanadium sodium phosphate by separation of nucleation and crystallization" disclosed in Chinese patent application No. CN114604842A), etc.), enabling the production of nano-sized vanadium sodium phosphate. By effectively controlling the particle size of vanadium sodium phosphate, the electron and ion transport efficiency of vanadium sodium phosphate can be improved, thereby enhancing its sodium storage performance. However, the use of large amounts of solvent in the liquid-phase synthesis process and the washing of crude products generate large amounts of wastewater, which not only increases manufacturing costs but also leads to the waste of raw material resources. Until now, there has been no practical solution to this problem. [Overview of the project] [Problems that the invention aims to solve]

[0004] In view of the challenges and difficulties in the manufacturing and application processes of vanadium sodium phosphate materials, this invention proposes a method for manufacturing vanadium sodium phosphate nanomaterials; by combining the principles of atomic economy, it efficiently manufactures nano-sized vanadium sodium phosphate using a high-power, high-speed polishing device; it also achieves efficient utilization of raw material atoms, eliminating the generation of excess waste and waste of raw materials, and eliminating solvent discharge and wastewater treatment processes from the washing process, thus realizing environmentally friendly manufacturing; high-speed collision and reaction acceleration are achieved by the high-power, high-speed polishing device, effectively controlling the particle size of the product and realizing the manufacture of nano-sized products; and the manufacturing method has advantages such as being easy to operate, highly efficient, and easy to scale up industrially, thus contributing to the advancement of research, dissemination, and application in the field of electrochemical energy storage of vanadium sodium phosphate materials. [Means for solving the problem]

[0005] To achieve the above objective, the present invention employs the following technical means. It is in the form of nanoparticles and its chemical formula is Na2+x(VOPO4)2F x A method for producing vanadium sodium phosphate nanomaterials where yH2O (where x=0 or 1, y=0~2), 1) A raw material consisting of tetravalent vanadium, sodium phosphate, and sodium fluoride, or a raw material consisting of tetravalent vanadium and sodium phosphate, is converted to Na2+x(VOPO4)2F x • A step of weighing out the raw materials in a blending ratio based on the atomic ratio of yH2O; and 2) A method for producing vanadium sodium phosphate nanomaterials, comprising the steps of: feeding raw materials into a high-speed homogenizing abrasive machine; controlling the rotation speed of the high-speed homogenizing abrasive machine to 1000 to 5000 rpm and performing forward or reverse rotation for at least 10 minutes; and sequentially completing a crystallization growth control process by controlling the rotation speed of the high-speed homogenizing abrasive machine to 300 to 1000 rpm and performing forward and reverse rotation alternately for at least 15 minutes per rotation, thereby obtaining a target product by adjusting the rotation speed of the high-speed homogenizing abrasive machine and the reaction time.

[0006] Furthermore, in step 1), the tetravalent vanadium is one or two selected from VO2 and VOOH.

[0007] Furthermore, in step 1), the sodium salt of phosphoric acid is one or two selected from Na2HPO4 and NaH2PO4.

[0008] Furthermore, in step 2), the high-speed homogenization polishing machine is a herbal medicine grinder, a colloidal mill, or a planetary ball mill.

[0009] Furthermore, in step 2), an interval of at least 10 minutes is provided when switching between forward and reverse rotation.

[0010] Furthermore, the particle size of the manufactured sodium vanadium phosphate is 100 nm or less. [Effects of the Invention]

[0011] Compared to the prior art, the present invention offers the following beneficial effects. 1) By combining the principle of atomic economy with "rapid nucleation + crystal growth control," we will achieve the efficient and environmentally friendly production of vanadium sodium phosphate material with controllable particle size distribution.

[0012] 2) By maximizing the utilization rate of each atom in the reaction raw materials based on the principle of atomic economy, the residue of excess raw materials and the generation of waste liquids, waste gases, and solid waste are avoided. Since conventional processes such as the treatment of waste liquids, waste gases, and solid waste, and the washing and drying of reaction products are eliminated, manufacturing costs are reduced.

[0013] 3) The high centrifugal force and shear force of high-speed homogenization polishing machines such as colloid mills cause the reaction raw materials to rotate and collide at high speed within the polishing machine, thereby obtaining the activation energy necessary for the reaction. By minimizing mass transfer resistance, the collision probability is greatly improved, rapidly forming a large number of fine nanocrystalline nuclei, promoting the rapid onset of the reaction, rapidly nucleating sodium vanadium phosphate, and effectively achieving the separation of the "nucleation and crystallization" processes. By controlling the reaction frequency and time, the crystallization growth process is controlled, the bonding and growth of crystal nuclei are controlled, and the objective of controlling the particle size of the sodium vanadium phosphate material is achieved, realizing efficient adjustment and control of sodium vanadium phosphate at the nanoscale.

[0014] 4) This not only effectively avoids the generation of waste liquids, waste gases, and solid waste, simplifies the process, and reduces manufacturing costs, but also effectively adjusts and controls the particle size of vanadium sodium phosphate particles, enabling the production of products with an average particle size controlled to the nanometer order.

[0015] 5) The manufacturing conditions are environmentally friendly, simple, highly efficient, and easy to scale up.

[0016] 6) The resulting product has advantages in terms of structure and performance. Nano-sizing of vanadium sodium phosphate improves the conductivity and electrolyte wettability of the material, and demonstrates excellent electrochemical performance. This improves the application limits of vanadium sodium phosphate-based materials in the energy storage field, and makes it promising for application as electrode materials in alkali metal secondary batteries such as lithium, sodium, and potassium. [Brief explanation of the drawing]

[0017] [Figure 1]XRD pattern of the sodium vanadium phosphate material manufactured in Example 1 of the present invention. [Figure 2] Particle size distribution diagram of the sodium vanadium phosphate material manufactured in Example 1 of the present invention. [Figure 3] SEM image of the sodium vanadium phosphate material manufactured in Example 2 of the present invention. [Figure 4] Cyclic voltammogram of the sodium vanadium phosphate material manufactured in Example 2 of the present invention. [Figure 5] Constant current charge-discharge curve of the sodium vanadium phosphate material manufactured in Example 3 of the present invention.

Mode for Carrying Out the Invention

[0018] In the present invention, the sodium vanadium phosphate has a chemical formula of Na 2+x (VOPO4)2F x ·yH2O (where x = 0 or 1, y = 0 to 2), has a microscopic form of nanoparticles, a narrow particle size distribution of the nanoparticles, and a high specific surface area.

[0019] The present invention manufactures a sodium vanadium phosphate material by a method combining the principle of atom economy and "rapid nucleation + crystallization growth control", and the specific steps are as follows.

[0020] 1) Weigh the raw materials. The raw materials consist of tetravalent vanadium, a sodium salt of phosphoric acid, and sodium fluoride, or consist of tetravalent vanadium and a sodium salt of phosphoric acid. The tetravalent vanadium is one or two selected from VO2 and VOOH. The sodium salt of phosphoric acid is one or two selected from Na2HPO4 and NaH2PO4. The mixing ratio of the raw materials is based on the principle of atom economy. That is, the mixing ratio of the raw materials is based on the atomic ratio of Na2+x(VOPO4)2F x ·yH2O.

[0021] [[ID=३7]] 2) The raw materials in the above-mentioned proportions are fed into a high-speed homogenization polishing machine, and the rotation speed and reaction time of the high-speed homogenization polishing machine are adjusted to realize a "rapid nucleation + crystal growth control" process. Specifically, in the rapid nucleation process, the rotation speed of the high-speed homogenization polishing machine is set to 1000-5000 rpm, and forward or reverse rotation is performed for at least 10 minutes. In the crystal growth control process, the rotation speed of the high-speed homogenization polishing machine is set to 300-1000 rpm, and forward and reverse rotation are performed alternately for at least 15 minutes per rotation, 1 to 5 times each. After the reaction, the target product, sodium vanadium phosphate, is obtained without the need for washing or drying.

[0022] Examples of the aforementioned high-speed homogenization polishing machines include herbal medicine grinders, colloidal mills, and planetary ball mills. When switching between forward and reverse rotation, an interval of at least 10 minutes should be provided.

[0023] The method for producing vanadium sodium phosphate material according to the present invention avoids the problems of solvent discharge in conventional manufacturing processes and the treatment of wastewater generated in washing processes, enabling efficient use of raw materials and an extremely high atom utilization rate, thereby realizing environmentally friendly manufacturing.

[0024] The method for producing vanadium sodium phosphate material according to the present invention can effectively adjust and control the particle size of vanadium sodium phosphate particles, enabling the production of materials with an average particle size controlled to the nanometer order. The produced vanadium sodium phosphate has good electrochemical performance when used as an electrode material and can be used as an electrode material for alkali metal secondary batteries such as lithium, sodium, and potassium. [Examples]

[0025] To illustrate the present invention more clearly, embodiments of the present invention will be further described with reference to examples. The following examples are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. Any technical means (including simple modifications and equivalent substitutions) that a person skilled in the art can obviously derive within the technical scope disclosed herein are all included within the scope of protection of the present invention.

Example

[0026] 0.2 mol of VO₂, 0.1 mol of NaF and 0.2 mol of NaH₂PO₄ were weighed out, and the atomic ratio was Na:V:P:F:H:O = 3:2:2:1:4:12. The three raw materials were put into a Chinese herbal medicine grinder. After grinding at a rotation speed of 3000 rpm for 10 min in the forward rotation, the rotation speed was adjusted to 600 rpm, and the forward rotation and reverse rotation were each performed once alternately at 15 min / rotation for grinding. After the reaction was completed, a sodium vanadium phosphate material was obtained by sieving with a steel wire mesh. The chemical formula of the obtained sodium vanadium phosphate material is Na₃(VOPO₄)₂F·2H₂O (corresponding to the case of x = 1 and y = 2 in the chemical formula Na 2+ ₓ(VOPO₄)₂F x ·yH₂O).

Example

[0027] [[ID=I6]] 0.1 mol of VO₂ and 0.1 mol of NaH₂PO₄ were weighed out, and the atomic ratio was Na:V:P:H:O = 1:1:1:2:6. The three raw materials were put into a colloid mill. After grinding at a rotation speed of 5000 rpm for 10 min in the forward rotation, the rotation speed was adjusted to 1000 rpm, and the forward rotation and reverse rotation were each performed 3 times alternately at 15 min / rotation for grinding. After the reaction was completed, a sodium vanadium phosphate material was obtained by sieving with a steel wire mesh. The chemical formula of the obtained sodium vanadium phosphate material is Na₂(VOPO₄)₂·H₂O (corresponding to the case of x = 0 and y = 1 in the chemical formula Na 2+ ₓ(VOPO₄)₂F x ·yH₂O), which can be represented as 2NaVOPO₄·H₂O and can be further simplified to NaVOPO₄·H₂O.

Example

[0028] 0.2 mol of VOOH, 0.1 mol of NaF, and 0.2 mol of Na2HPO4 were weighed out, with an atomic ratio of Na:V:P:F:H:O = 3:2:2:1:4:12. The three raw materials were placed in a planetary ball mill. After polishing by rotating in the forward direction at a speed of 1000 rpm for 10 minutes, the rotation speed was adjusted to 500 rpm, and polishing was performed by alternating forward and reverse rotations for 15 minutes each, five times. After the reaction was complete, the sodium vanadium phosphate material was obtained by sieving through a steel wire mesh. The chemical formula of the obtained sodium vanadium phosphate material is Na3(VOPO4)2F·2H2O(chemical formula Na 2+ x(VOPO4)2F x This corresponds to the case where x=1 and y=2 in yH2O.

[0029] Figure 1 shows the XRD pattern of the vanadium sodium phosphate material produced in Example 1. As can be seen from Figure 1, the characteristic diffraction peaks of the pattern coincide with the peak positions of the standard card PDF#01-076-3645, indicating that the produced sample product is vanadium sodium phosphate (Na3(VOPO4)2F·2H2O), and the strong intensity of the characteristic diffraction peaks in the XRD indicates that the obtained sample product has good crystallinity.

[0030] Figure 2 shows the particle size distribution of the vanadium sodium phosphate material produced in Example 1. As can be seen from Figure 2, the produced vanadium sodium phosphate has small particle sizes (less than 100 nm) and a narrow particle size distribution.

[0031] Figure 3 shows an SEM image of the vanadium sodium phosphate material produced in Example 2. As can be seen from Figure 3, the produced vanadium sodium phosphate has a microscopic morphology of nanoparticles, with a narrow particle size distribution of nanoparticles, mainly around 100 nm.

[0032] Figure 4 shows the cyclic voltammogram (CV) of the vanadium sodium phosphate material produced in Example 2. As can be seen from Figure 4, the produced vanadium sodium phosphate has a reversible redox characteristic peak, exhibits good sodium ion insertion and deinsertion performance, and can be used as an electrode material for sodium ion secondary batteries.

[0033] Figure 5 shows the constant current charge-discharge curve of the sodium vanadium phosphate material produced in Example 3. As can be seen from Figure 5, under a charge-discharge current density of 0.1C, the specific capacity of the produced sodium vanadium phosphate is 103.1 mAh / g, indicating a good discharge specific capacity.

[0034] The above describes only preferred embodiments of the present invention and does not limit the scope of protection of the present invention. Equivalent substitutions and modifications made by those skilled in the art based on the technical means and inventive concept of the present invention within the technical scope disclosed herein are all included within the scope of protection of the present invention.

Claims

1. It is in the form of nanoparticles and its chemical formula is Na ２ +x(VOPO) ４ ) ２ F ｘ ・yH ２ A method for producing vanadium sodium phosphate nanomaterials where O (where x = 0 or 1, y = 0 to 2), 1) Weighing the raw material composed of tetravalent vanadium, sodium salt of phosphoric acid, and sodium fluoride, or the raw material composed of tetravalent vanadium and sodium salt of phosphoric acid, according to the blending ratio of the raw materials based on the atomic ratio of Na ２ +x(VOPO ４ ) ２ F ｘ ・yH ２ O; and 2) A method for producing vanadium sodium phosphate nanomaterials, characterized by comprising the steps of: feeding raw materials into a high-speed homogenizing polishing machine; controlling the rotation speed of the high-speed homogenizing polishing machine to 1,000 to 5,000 rpm and performing a rapid nucleation process in which forward or reverse rotation is performed for at least 10 mins; and controlling the rotation speed of the high-speed homogenizing polishing machine to 300 to 1,000 rpm and performing a crystallization growth control process in which forward and reverse rotation are performed alternately for at least 15 mins per rotation, 1 to 5 times each, by adjusting the rotation speed of the high-speed homogenizing polishing machine and the reaction time to obtain a target product.

2. In step 1) above, tetravalent vanadium is VO ２ A method for producing vanadium sodium phosphate nanomaterials according to claim 1, characterized in that it is one or two selected from and VOOH.

3. In step 1) above, the sodium salt of phosphoric acid is Na ２ HPO ４ and NaH ２ PO ４ A method for producing vanadium sodium phosphate nanomaterials according to claim 1, characterized in that it is one or two selected from the above.

4. The method for producing vanadium sodium phosphate nanomaterials according to claim 1, characterized in that in step 2) the high-speed homogenization polishing machine is a herbal medicine grinder, a colloidal mill, or a planetary ball mill.

5. The method for producing vanadium sodium phosphate nanomaterials according to claim 1, characterized in that, in step 2), an interval of at least 10 min is provided when switching between forward rotation and reverse rotation.

6. A method for producing vanadium sodium phosphate nanomaterials according to claim 1, characterized in that the particle size of the produced vanadium sodium phosphate is 100 nm or less.

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