A flaky nano tungsten acid, its preparation method and application

Abstract

The present invention belongs to the technical field of tungsten metallurgy, and specifically relates to a flaky nano-tungstic acid, a preparation method thereof and an application. The preparation method includes: S1. Add hydrochloric acid into a container, continuously stir during the adding process and keep the temperature in the container stable; S2. Spray 8 - 10 mL of sodium tungstate solution B into the container, continuously stir during the adding process and keep the temperature in the container stable; S3. Spray 0.5 - 1.0 L of sodium tungstate solution A into the container, continuously stir during the adding process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 2.5 - 4.0 times the theoretical amount of hydrochloric acid required for preparing tungstic acid according to the concentration of tungstate in sodium tungstate solution A; S4. Repeat steps S1 and S3; S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it, and flaky nano-tungstic acid with complete crystal development can be stably prepared, and its thickness is less than 100 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of tungsten metallurgy, and particularly relates to a flaky nano tungstic acid, a preparation method thereof and an application thereof. Background Art

[0002] Caesium tungsten bronze (Cs x WO3) has great research value in aspects such as transparent heat-insulating coatings, photocatalysis, energy-saving materials and sensor carriers due to its broad absorption spectrum. Due to the quantum confinement effect, 2D nanomaterials have many physical, chemical, electrical and optical properties that cannot be achieved in the original material structure. In recent years, as a candidate material for a new near-infrared absorbing material, a large number of researchers have conducted in-depth research on caesium tungsten bronze nanosheets.

[0003] Tungstic acid is one of the raw materials for preparing caesium tungsten bronze. Its original particle size, morphology and crystal development degree will affect the morphology and crystal development degree of caesium tungsten bronze, and thus affect the overall performance of caesium tungsten bronze. For example, if the original crystal development of tungstic acid is incomplete, problems such as uneven pores, increased thermal conductivity, decreased mechanical strength and reduced durability will occur in caesium tungsten bronze. Summary of the Invention

[0004] To solve the problems existing in the prior art, the main object of the present invention is to propose a flaky nano tungstic acid, a preparation method thereof and an application thereof.

[0005] According to one aspect of the present invention, the following technical solution is provided:

[0006] A preparation method of flaky nano tungstic acid, comprising the following steps:

[0007] S1. Add hydrochloric acid to a container, continuously stir during the addition process and keep the temperature in the container stable;

[0008] S2. Add 8-10 mL of sodium tungstate solution B to the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable;

[0009] S3. Add 0.5-1.0 L of sodium tungstate solution A to the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 2.5-4.0 times the theoretical amount of hydrochloric acid required to prepare tungstic acid according to the tungstate ion concentration in sodium tungstate solution A;

[0010] S4. Repeat steps S1 and S3;

[0011] S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it to obtain flaky nano tungstic acid.

[0012] According to another aspect of the present invention, the present invention provides the following technical solutions:

[0013] A flaky nano tungsten acid is prepared by using the preparation method of the flaky nano tungsten acid described above. The crystal development of the flaky nano tungsten acid is complete, and its thickness is less than 100 nm.

[0014] According to another aspect of the present invention, the present invention provides the following technical solutions:

[0015] An application of a flaky nano tungsten acid in the field of preparing cesium tungsten bronze.

[0016] The beneficial effects of the present invention are as follows:

[0017] The present invention provides a flaky nano tungsten acid, a preparation method and an application thereof. The preparation method includes: S1. Add hydrochloric acid to a container, and continuously stir during the addition process to keep the temperature in the container stable; S2. Spray 8-10 mL of sodium tungstate solution B into the container, and continuously stir during the addition process to keep the temperature in the container stable; S3. Spray 0.5-1.0 L of sodium tungstate solution A into the container, and continuously stir during the addition process to keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 2.5-4.0 times the theoretical amount of hydrochloric acid required to prepare tungstic acid according to the concentration of tungstate ions in sodium tungstate solution A; S4. Repeat steps S1 and S3; S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it, and a flaky nano tungsten acid with complete crystal development and a thickness less than 100 nm can be stably prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0019] Figure 1 It is the electron microscope image of the flaky nano tungsten acid prepared in Example 1 of the present invention;

[0020] Figure 2 It is the electron microscope image of the flaky nano tungsten acid prepared in Example 2 of the present invention;

[0021] Figure 3 It is the electron microscope image of the flaky nano tungsten acid prepared in Example 3 of the present invention;

[0022] Figure 4 It is the electron microscope image of the tungstic acid prepared in Comparative Example 1 of the present invention;

[0023] Figure 5Electron micrograph of tungstic acid prepared in Comparative Example 2 of the present invention;

[0024] Figure 6 Electron micrograph of tungstic acid prepared in Comparative Example 3 of the present invention;

[0025] Figure 7 Electron micrograph of tungstic acid prepared in Comparative Example 4 of the present invention.

[0026] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0027] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The present invention provides a flaky nano tungstic acid, a preparation method and an application thereof. At a certain temperature, by using the method of pre-preparing seeds and adding materials in stages, flaky nano tungstic acid with complete crystal development of tungstic acid crystals is prepared. Alternately adding hydrochloric acid and sodium tungstate solution A can keep the concentration of hydrochloric acid in the reaction system within a relatively stable range all the time, can control the reaction rate and the concentration of solutes in the solution, and make the particle size of the formed tungstic acid more uniform. If hydrochloric acid is not added alternately in batches, the concentration of hydrochloric acid will become lower and lower, resulting in tungstic acid with greatly different sizes and morphologies.

[0029] According to one aspect of the present invention, the present invention provides the following technical solutions:

[0030] A preparation method of flaky nano tungstic acid, comprising the following steps:

[0031] S1. Add hydrochloric acid to a container, continuously stir during the adding process and keep the temperature in the container stable;

[0032] S2. Spray 8-10 mL of sodium tungstate solution B into the container, continuously stir during the adding process and keep the temperature in the container stable;

[0033] S3. Spray 0.5-1.0 L of sodium tungstate solution A into the container, continuously stir during the adding process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 2.5-4.0 times the theoretical amount of hydrochloric acid required to prepare tungstic acid according to the concentration of tungstate in sodium tungstate solution A;

[0034] S4. Repeat steps S1 and S3;

[0035] S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it to obtain flaky nano tungstic acid.

[0036] Preferably, in the steps S1 - S3, the temperature in the container is 80 - 95°C, and the stirring speed is 150 - 250 r / min. Temperature has a great influence on the nucleation and reaction rate. When the temperature is low, the morphology of the formed crystal nuclei is often irregular; when the temperature is high, the surface of the crystal nuclei is wrapped by high - density packed planes. Specifically, the temperature in the container can be any one of, for example, 80°C, 85°C, 90°C, 95°C or the range between any two of them. If the stirring speed is too low, tungstic acid is prone to deposit and grow, resulting in a low specific surface area; if the stirring speed is too high, tungstic acid is easily broken, with poor crystal form and poor uniformity. Specifically, the stirring speed can be any one of, for example, 150 r / min, 175 r / min, 200 r / min, 225 r / min, 250 r / min or the range between any two of them.

[0037] Preferably, in the step S1, the concentration of hydrochloric acid is 16 - 22 wt%; there is no special requirement for the addition speed of hydrochloric acid, and it can be added as soon as possible; for example, each time hydrochloric acid is added, it can be added within 5 - 10 s. As a reactant for preparing tungstic acid, the concentration of hydrochloric acid also affects both nucleation and growth. If the concentration of hydrochloric acid is too high, the probability of hydrogen ions combining with tungstate ions becomes larger, the local reaction is too fast, and a small number of large crystal seeds are obtained, ultimately causing excessive crystal development and too large crystal size; if the concentration of hydrochloric acid is too low, the supersaturation is low, numerous small and uneven crystal nuclei will be formed, and the growth and development are slow, ultimately obtaining crystals with extremely large differences in morphology and size. Specifically, the concentration of hydrochloric acid can be any one of, for example, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt%, 20 wt%, 20.5 wt%, 21 wt%, 21.5 wt%, 22 wt% or the range between any two of them.

[0038] Preferably, in the step S2, the concentration of sodium tungstate solution B is 150-200 g / L in terms of WO3; in the step S3, the concentration of sodium tungstate solution A is 150-200 g / L in terms of WO3. Specifically, the concentration of sodium tungstate solution B and the concentration of sodium tungstate solution A can be the same or different. The tungsten concentration of the reactants has an impact on both the nucleation and the growth and development of the crystal. Too low a concentration will result in a large number of nuclei, slow growth and development, and incomplete crystal development; too high a concentration will lead to too fast a growth rate, less nucleation of the product and rapid development, forming coarse particles. Specifically, the concentration of sodium tungstate solution A can be, for example, any one of 150 g / L, 155 g / L, 160 g / L, 165 g / L, 170 g / L, 175 g / L, 180 g / L, 185 g / L, 190 g / L, 195 g / L, 200 g / L or the range between any two of them; the concentration of sodium tungstate solution B can be, for example, any one of 150 g / L, 155 g / L, 160 g / L, 165 g / L, 170 g / L, 175 g / L, 180 g / L, 185 g / L, 190 g / L, 195 g / L, 200 g / L or the range between any two of them.

[0039] Preferably, in the step S2, 8-10 mL of sodium tungstate solution B is added to the container by spraying and then stirred for 8-12 min. Spray feeding can make the materials evenly distributed in the reaction system, avoid too high local concentration, and improve the uniformity of the product; it can also increase the reaction area and accelerate the reaction rate. Specifically, the amount of sodium tungstate solution B can be any one of 8 mL, 9 mL, 10 mL or the range between any two of them. At the same time, the spraying speed of 8-10 mL of sodium tungstate solution B is controlled to be 50-80 mL / min. Specifically, the spraying speed of 8-10 mL of sodium tungstate solution B can be, for example, any one of 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min or the range between any two of them.

[0040] Preferably, in the step S3, sodium tungstate solution A is added by a peristaltic pump; the addition rate of sodium tungstate solution A is 50 - 120 mL / min; after the addition of sodium tungstate solution A is completed, stir for 2 - 3 min and then proceed to step S4. Specifically, the addition rate of sodium tungstate solution A can be, for example, any one of 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, 100 mL / min, 110 mL / min, 120 mL / min or the range between any two of them; the stirring time after the addition of sodium tungstate solution A is completed can be any one of 2 min, 2.5 min, 3 min or the range between any two of them. The volume of sodium tungstate solution A can be, for example, any one of 0.5 L, 0.55 L, 0.6 L, 0.65 L, 0.7 L, 0.75 L, 0.8 L, 0.85 L, 0.9 L, 0.95 L, 1.0 L or the range between any two of them; the dosage of hydrochloric acid can be any one of 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, 4.0 times the theoretical amount of dilute hydrochloric acid required to prepare tungstic acid according to the tungstate ion concentration in sodium tungstate solution A or the range between any two of them.

[0041] Preferably, in the step S4, repeat 3 - 6 times and then proceed to step S5. Specifically, the number of repetitions can be 3, 4, 5, or 6.

[0042] Preferably, in the step S5, the concentration of hydrochloric acid is 2 wt%, wash 2 - 4 times, and the drying temperature is 100 - 120 °C. Adopting a relatively high drying temperature is beneficial to the volatilization of residual hydrochloric acid in tungstic acid at this drying temperature, but if the temperature is too high, the water evaporates too quickly and it is not easy to obtain loose tungstic acid. Specifically, the drying temperature can be, for example, any one of 100 °C, 105 °C, 110 °C, 115 °C, 120 °C or the range between any two of them.

[0043] According to another aspect of the present invention, the present invention provides the following technical solution:

[0044] A sheet-like nano-tungstic acid is prepared by the above-mentioned preparation method of sheet-like nano-tungstic acid. The sheet-like nano-tungstic acid has complete crystal development, is a two-dimensional nano material, and its thickness is less than 100 nm.

[0045] According to another aspect of the present invention, the present invention provides the following technical solution:

[0046] An application of the sheet-like nano-tungstic acid in the field of preparing cesium tungsten bronze.

[0047] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0048] Example 1

[0049] A preparation method of flaky nano tungstic acid, comprising the following steps:

[0050] S1. Add hydrochloric acid into a container, continuously stir during the adding process and keep the temperature in the container stable;

[0051] S2. Add 10 mL of sodium tungstate solution B into the container in a spray manner, continuously stir during the adding process and keep the temperature in the container stable;

[0052] S3. Add 0.8 L of sodium tungstate solution A into the container in a spray manner, continuously stir during the adding process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 3.0 times the theoretical amount of hydrochloric acid required to prepare tungstic acid according to the concentration of tungstate in sodium tungstate solution A;

[0053] S4. Repeat steps S1 and S3;

[0054] S5. Filter the obtained tungstic acid, wash it with hydrochloric acid and then dry it to obtain flaky nano tungstic acid.

[0055] In the above steps S1 - S3, the temperature in the container is 90 °C, the stirring speed is 200 r / min. The concentration of hydrochloric acid is 20 wt%. In step S2, the concentration of sodium tungstate solution B is 200 g / L calculated as WO3; in step S3, the concentration of sodium tungstate solution A is 200 g / L calculated as WO3. In step S2, after adding 10 mL of sodium tungstate solution B into the container in a spray manner, stir for 10 min; the spray speed of sodium tungstate solution B is 60 mL / min. In step S3, sodium tungstate solution A is added using a peristaltic pump; the adding speed of sodium tungstate solution A is 66.67 mL / min; after the addition of sodium tungstate solution A is completed, stir for 2 min and then proceed to step S4. In step S4, repeat 5 times and then proceed to step S5. In step S5, the concentration of hydrochloric acid is 2 wt%, wash 3 times, and the drying temperature is 110 °C.

[0056] The electron microscope image of the flaky nano tungstic acid obtained in this example is as Figure 1 shown, its thickness is less than 100 nm, it is a two-dimensional nano material, the crystal grains are completely developed, and the surface is smooth.

[0057] Example 2

[0058] A preparation method of flaky nano tungstic acid, comprising the following steps:

[0059] S1. Add hydrochloric acid into a container, continuously stir during the adding process and keep the temperature in the container stable;

[0060] S2. Add 8 mL of sodium tungstate solution B into the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable;

[0061] S3. Add 1.0 L of sodium tungstate solution A into the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 4.0 times the theoretical amount of hydrochloric acid required for preparing tungstic acid according to the concentration of tungstate ions in sodium tungstate solution A;

[0062] S4. Repeat steps S1 and S3;

[0063] S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it to obtain flaky nano-tungstic acid.

[0064] In the above steps S1 - S3, the temperature in the container is 85 °C, the stirring speed is 200 r / min. The concentration of hydrochloric acid is 16 wt%. In step S2, calculated as WO3, the concentration of sodium tungstate solution B is 180 g / L; in step S3, calculated as WO3, the concentration of sodium tungstate solution A is 180 g / L. In step S2, after adding 8 mL of sodium tungstate solution B into the container in a spray manner, stir for 10 min; the spray speed of sodium tungstate solution B is 80 mL / min. In step S3, sodium tungstate solution A is added using a peristaltic pump; the addition speed of sodium tungstate solution A is 83.33 mL / min; after the addition of sodium tungstate solution A is completed, stir for 2 min and then proceed to step S4. In step S4, repeat 4 times and then proceed to step S5. In step S5, the concentration of hydrochloric acid is 2 wt%, wash 3 times, and the drying temperature is 120 °C.

[0065] The electron microscope image of the flaky nano-tungstic acid obtained in this example is as Figure 2 shown. Its thickness is less than 100 nm, it is a two-dimensional nano-material, the crystal grains are well-developed and the surface is smooth.

[0066] Example 3

[0067] A method for preparing flaky nano-tungstic acid, comprising the following steps:

[0068] S1. Add hydrochloric acid into the container, continuously stir during the addition process and keep the temperature in the container stable;

[0069] S2. Add 10 mL of sodium tungstate solution B into the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable;

[0070] S3. Add 0.6 L of sodium tungstate solution A into the container in a spray manner, continuously stir during the addition process and keep the temperature in the container stable; the amount of hydrochloric acid added in step S1 is 2.5 times the theoretical amount of hydrochloric acid required for preparing tungstic acid according to the concentration of tungstate ions in sodium tungstate solution A;

[0071] S4. Repeat steps S1 and S3;

[0072] S5. Filter the obtained tungstic acid, wash it with hydrochloric acid, and then dry it to obtain flaky nano - tungstic acid.

[0073] In the above - mentioned steps S1 - S3, the temperature inside the container is 95 °C, the stirring speed is 200 r / min, and the concentration of hydrochloric acid is 22 wt%. In step S2, based on WO3, the concentration of sodium tungstate solution B is 190 g / L; in step S3, based on WO3, the concentration of sodium tungstate solution A is 190 g / L. In step S2, 10 mL of sodium tungstate solution B is added to the container by spraying and then stirred for 10 min; the spraying speed of sodium tungstate solution B is 50 mL / min. In step S3, sodium tungstate solution A is added using a peristaltic pump; the adding speed of sodium tungstate solution A is 55.56 mL / min; after the addition of sodium tungstate solution A is completed, it is stirred for 2 min and then step S4 is carried out. In step S4, after repeating 4 times, step S5 is carried out. In step S5, the concentration of hydrochloric acid is 2 wt%, it is washed 3 times, and the drying temperature is 120 °C.

[0074] The electron micrograph of the flaky nano - tungstic acid obtained in this example is as Figure 3 shown. Its thickness is less than 100 nm, it is a two - dimensional nanomaterial, the crystal grains are well - developed, and the surface is smooth.

[0075] Comparative Example 1

[0076] The difference from Example 1 is that in steps S1 - S3, the temperature inside the container is 105 °C.

[0077] The electron micrograph of the tungstic acid obtained in this comparative example is as Figure 4 shown. Its thickness significantly exceeds 100 nm, which has exceeded the grain size of two - dimensional nanomaterials. The crystal grains are well - developed, and the surface is smooth.

[0078] Comparative Example 2

[0079] The difference from Example 1 is that in steps S1 - S3, the temperature inside the container is 45 °C.

[0080] The electron micrograph of the tungstic acid obtained in this comparative example is as Figure 5 shown. The tungstic acid is in the form of stacked flakes, the crystal grains are not well - developed, with irregular edges and a complex surface morphology.

[0081] Comparative Example 3

[0082] The difference from Example 1 is that hydrochloric acid and sodium tungstate solution A are not added in a segmented and alternating manner: that is, all hydrochloric acid is added first, then sodium tungstate solution B is added, and then all sodium tungstate solution A is added.

[0083] The electron micrograph of the tungstic acid obtained in this comparative example is as Figure 6 shown. The tungstic acid is flaky. There is tungstic acid with a thickness exceeding 200 nm and a smooth surface, and there is also tungstic acid with a thickness within 100 nm. At the same time, there are a large number of incompletely developed and complex-shaped nano-tungstic acids.

[0084] Comparative Example 4

[0085] The difference from Example 1 is that sodium tungstate solution A and sodium tungstate solution B are added in a dripping manner.

[0086] The electron micrograph of the tungstic acid obtained in this comparative example is as Figure 7 shown. The tungstic acid is in the form of completely developed flakes and agglomerates of fine particles, and there is a large difference in thickness between the flaky crystal grains.

[0087] The tungstic acids prepared in Example 1 and Comparative Example 4 and the cesium source are respectively used to prepare cesium tungsten bronze according to the same ratio, and their full infrared barrier and light transmittance properties are detected. The results are as follows:

[0088] The full infrared barrier rate of the cesium tungsten bronze film prepared with the tungstic acid prepared in Example 1 is 94.2%, and the light transmittance is 71.8%.

[0089] The full infrared barrier rate of the cesium tungsten bronze film prepared with the tungstic acid prepared in Comparative Example 4 is 78.5%, and the light transmittance is 53.6%.

[0090] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made using the content of the specification of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A preparation method of flaky nano-tungstic acid, characterized in that, It includes the following steps: S1. Add hydrochloric acid into the container, continuously stir during the adding process and keep the temperature in the container stable; S2. Add 8 - 10 mL of sodium tungstate solution B into the container in a spray manner, continuously stir during the adding process and keep the temperature in the container stable; S3. Add 0.5 - 1.0 L of sodium tungstate solution A into the container in a spray manner, continuously stir during the adding process and keep the temperature in the container stable; The amount of hydrochloric acid added in step S1 is 2.6 - 4.0 times the theoretical amount of hydrochloric acid required to prepare tungstic acid according to the concentration of tungstate in sodium tungstate solution A; S4. Repeat steps S1 and S3; S5. Filter the prepared tungstic acid, wash it with hydrochloric acid and then dry it to obtain flaky nano - tungstic acid. The flaky nano - tungstic acid has complete crystal development and is a two - dimensional nano - material with a thickness less than 100 nm; In steps S1 - S3, the temperature in the container is 85 - 95 °C.

2. The preparation method of the flaky nano tungstic acid according to claim 1, characterized in that, In steps S1 - S3, the stirring speed is 150 - 250 r / min.

3. The preparation method of the flaky nano-tungstic acid according to claim 1, wherein In step S1, the concentration of hydrochloric acid is 16 - 22 wt%.

4. The preparation method of the flaky nano-tungstic acid according to claim 1, characterized in that, In step S2, calculated as WO3, the concentration of sodium tungstate solution B is 150 - 200 g / L; In step S3, calculated as WO3, the concentration of sodium tungstate solution A is 150 - 200 g / L.

5. The preparation method of the sheet-like nanometer tungstic acid according to claim 1, characterized in that, In step S2, after adding 8 - 10 mL of sodium tungstate solution B into the container in a spray manner, stir for 8 - 12 min; The spray speed of sodium tungstate solution B is 50 - 80 mL / min.

6. The preparation method of the flaky nano-tungstic acid according to claim 1, characterized in that, In step S3, the adding speed of sodium tungstate solution A is 50 - 120 mL / min; After the addition of sodium tungstate solution A is completed, stir for 2 - 3 min and then proceed to step S4.

7. The preparation method of the flaky nano-tungstic acid according to claim 1, wherein, In step S4, repeat 3 - 6 times and then proceed to step S5.

8. The preparation method of the flaky nano-tungstic acid according to claim 1, characterized in that, In step S5, the concentration of hydrochloric acid is 2 wt%, wash 2 - 4 times, and the drying temperature is 100 - 120 °C.

9. A flaky nano tungsten acid, characterized in that, It is prepared by using the preparation method of the flaky nano - tungstic acid described in any one of claims 1 - 8.

10. An application of the flaky nano - tungstic acid described in claim 9 in the field of preparing cesium tungsten bronze.

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