Method for preparing ultrafine powder material and its application

Abstract

The application discloses a preparation method and application of superfine powder material; the method is characterized by optimizing the process of preparing granular material by means of spray combustion method through micro-explosion technology, so as to improve the spray combustion method, solve the problems of great difficulty in solvent atomization and few available precursors, improve and perfect the powder material processing means, and improve the performance of the obtained powder material product. The superfine powder material preparation method is simple in preparation process, few in steps and easy to synthesize, the prepared powder material is small in particle size, large in specific surface area and good in dispersity, and can be further used for preparing high-value-added products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance materials, in particular to a preparation method of ultra-fine powder material and application thereof. BACKGROUND

[0002] According to the difference in phase formation or grain structure length, the ultra-fine powder material can be divided into micron materials (1-5 μm), sub-micron materials (100 nm-1 μm) and nanometer materials (less than 100 nm). Based on the high mechanical strength, super-normal magnetic resistance and thermal and electrical properties, combined with the self-assembly effect, small size and quantum and surface effects of the nanometer material itself, the ultra-fine powder material can be widely applied in the fields of micro-electronic components, hydrogen storage materials, capacitive materials, light guide materials and biological sensing materials.

[0003] The preparation of the ultra-fine powder material can be divided into solid phase method, gas phase method, liquid phase method and spray combustion method, etc. by taking the self-geometric parameters, spatial distribution parameters and volume fraction of each micro-unit in the regulation system as the target, and by controlling the space limitation conditions, reaction kinetics factors, thermodynamic factors and other preparation conditions. The solid phase method, as a traditional method for preparing materials, generates a precursor through a double decomposition reaction, and then the ultra-fine powder is prepared by washing, grinding, calcining and grinding in sequence. The solid phase method has a simple overall process flow, easy-to-control reaction conditions, and high product yield and low cost, but has the disadvantages of uneven particle size and easy agglomeration. The gas phase method, represented by the chemical vapor deposition method, generates materials through chemical reactions between gaseous raw materials, and the prepared powder has high purity, small particle size and is not easy to agglomerate, and the product composition is controllable, but the method has strict requirements for the composition of raw materials, and has poor applicability compared with other preparation methods. According to the difference in the preparation process, the liquid phase method can be further divided into precipitation method, gel method, hydrothermal method and solvent thermal method, etc. The composition, shape and size of the product in the specific preparation process are easy to control, and the powder material with high chemical uniformity can be prepared for materials with complex composition, but impurities such as anions are easily introduced in the production process, resulting in low product purity. As a new method integrating solution combustion method and spray pyrolysis method, the spray pyrolysis method can prepare ultra-fine powder with uniform composition at a lower temperature based on the large amount of heat released by the redox reaction between metal salts and organic fuels in the solution, but the flame spray pyrolysis method generally uses liquid phase feeding, and the organic solvent used for atomization is difficult to use. In addition, the liquid phase feeding requires the metal precursor in the reaction process to have high solubility in the organic solution, which has high cost and limited selection.

[0004] Therefore, it is necessary to improve and perfect the existing preparation method of ultra-fine powder material to improve the product performance of the ultra-fine powder material. SUMMARY

[0005] To solve the above technical problems, the application provides a preparation method of superfine powder material and application thereof.

[0006] In a first aspect, the application provides a preparation method of superfine powder material, comprising the following steps:

[0007] (1) dissolving a first metal compound and an emulsifier in a first solvent to obtain a first solution;

[0008] (2) dissolving a second metal compound in a second solvent to obtain a second solution;

[0009] (3) mixing the first solution and the second solution to obtain a mixed emulsion, and performing atomization treatment on the mixed emulsion, and then combusting the obtained atomized droplets at high temperature to obtain the superfine powder material.

[0010] In some embodiments, the first metal compound is different from the second metal compound, and the first metal compound and the second metal compound comprise at least one of halide, carbonate, sulfate, hydroxide, organic salt, silicate, and metallocene compound of a metal element.

[0011] In some embodiments, the metal element comprises at least one of Li, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Zr, Nb, Mo, Ru, Rh, Pd, In, Sn, Cs, Ba, La, and Ce.

[0012] In some embodiments, the emulsifier comprises at least one of higher fatty acid salt, higher fatty alcohol sulfate, sulfonate, quaternary ammonium salt, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyol oleate, polyether, polyvinyl alcohol, hydroxyethyl cellulose, and dimethicone.

[0013] In some embodiments, a difference between a normal-temperature boiling point of the first solvent and a normal-temperature boiling point of the second solvent is greater than or equal to 5℃.

[0014] In some embodiments, the first solvent comprises at least one of hydrocarbon solvent, aprotic solvent, protic solvent, and inorganic solvent, and the second solvent is inorganic solvent.

[0015] In some embodiments, the hydrocarbon solvent comprises at least one of toluene, xylene, n-heptane, n-decane, n-hexadecane, gasoline, diesel, and kerosene, the aprotic solvent comprises at least one of methyl benzoate, ethyl benzoate, tetrahydrofuran, pyridine, dichloromethane, bromobenzene, acetone, and diethyl ether, the protic solvent comprises at least one of diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol, and ethylene glycol, and the inorganic solvent comprises water.

[0016] In some embodiments, the first solvent and the second solvent are not completely miscible.

[0017] In some embodiments, in the step (3), the combustion-supporting gas used in the combustion process is air or oxygen.

[0018] In some embodiments, in the step (3), the particle size of the ultrafine powder material can be regulated between micron and nanometer levels, and the morphology of the ultrafine powder material includes at least one of a polyhedral structure exposing a high-index crystal plane, a solid structure, a hollow structure, and a core-shell structure.

[0019] In a second aspect, the embodiments of the present application provide an application of the preparation method of the ultrafine powder material in the preparation of a catalyst, a battery electrode, and a solid-state electrolyte.

[0020] From the above technical solutions, the present application provides a brand-new preparation method of an ultrafine powder material. The process of preparing a granular material by a spray combustion method is optimized by means of a micro-explosion technology to improve the deficiencies of the spray combustion method, such as great difficulty in solvent atomization, and few available precursors, thereby improving and perfecting the powder material processing means, and improving the performance of the obtained powder material product. The preparation method of the ultrafine powder material provided by the present application has simple preparation process, few steps, and easy synthesis. The prepared powder material has small particle size, large specific surface area, and good dispersity, and can be further used to prepare high-value-added products.

[0021] Compared with the traditional spray pyrolysis method, the preparation method of the ultrafine powder material proposed in the present application can regulate various morphologies including a polyhedral structure exposing a high-index crystal plane, a solid structure, a hollow structure, and a core-shell structure, effectively reduce the difficulty of solvent atomization, expand the types of available metal precursors, have wider raw material sources, lower production cost, and better product performance, and has important significance for improving and perfecting the powder material processing means and improving the performance of related products. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present specification, the present specification will be described more fully below. The present specification can be implemented in many different forms without departing from the core spirit of the present specification, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present specification more thorough and comprehensive.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this specification belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the specification. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] Flame spray pyrolysis, as a new method integrating solution combustion method and spray pyrolysis method, can produce ultrafine powders with uniform composition at a lower temperature based on the large amount of heat released by the redox reaction between metal salts and organic fuels in the solution. This method has the following characteristics: (1) low-temperature ignition can achieve self-sustaining combustion, releasing a large amount of heat and gas, and reaching high temperature instantaneously; (2) accurate stoichiometric ratio and high uniformity; (3) simple process equipment, fast synthesis and energy saving. Despite the above advantages, spray pyrolysis still has the following disadvantages: spray pyrolysis generally uses liquid-phase feed, and the organic solvent used is difficult to atomize; in addition, liquid-phase feed requires the metal precursor to have high solubility in organic solution, which is costly and has limited selection.

[0025] "Micro-explosion" refers to the process in which an emulsion formed by mixing liquids with different boiling points is atomized into a high-temperature environment, and then rapidly expands in volume and vaporizes into an aerosol state. After micro-explosion, the droplet diameter is significantly reduced, the atomization performance is greatly improved, and the heat and mass transfer efficiency is excellent, which can effectively strengthen the mass and heat transfer of the combustion process, improve the product yield and product performance. Based on the above characteristics, the micro-explosion process is applied to the preparation of powder materials by spray pyrolysis, the atomization of water-soluble solvents is less difficult, and the types of metal precursors that can be used are effectively expanded; in addition, compared with organic solvents, water-soluble solvents can produce a wider range of flame temperature fields during combustion, and can produce more diverse powder materials. Compared with traditional spray pyrolysis, micro-explosion enhanced flame spray pyrolysis technology has a wider source of raw materials, lower production cost and better product performance, which is of great significance for improving and perfecting the processing method of powder materials and improving the performance of related products. However, in the current preparation process of ultrafine powder materials, most of them are still based on spray combustion method as the core preparation method, and the micro-explosion technology is not involved in the strengthening of spray combustion method.

[0026] To this end, in a first aspect, the embodiments of the present application provide a preparation method of ultrafine powder material, comprising the following steps:

[0027] (1) dissolving a first metal compound and an emulsifier in a first solvent to obtain a first solution;

[0028] (2) dissolving a second metal compound in a second solvent to obtain a second solution;

[0029] (3) mixing the first solution and the second solution to obtain a mixed emulsion, and performing atomization treatment on the mixed emulsion, and obtaining the ultrafine powder material after the atomized droplets are combusted at high temperature.

[0030] In the embodiments of the present application, the first solution, the second solution and the mixed emulsion are kept in the emulsion state after emulsion processing. The emulsion processing can adopt ultrasonic emulsification, mechanical emulsification and membrane emulsification process means. Moreover, the mixed emulsion needs to be kept in the emulsion state before combustion, and the emulsion is ignited and combusted by atomization. The atomization treatment can adopt two-fluid atomization, ultrasonic atomization and pressure atomization process means.

[0031] In some embodiments, the first metal compound is different from the second metal compound, the first metal compound and the second metal compound include at least one of halide, carbonate, sulfate, hydroxide, organic salt, silicate and metallocene compound of a metal element, and the metal element includes at least one of Li, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Zr, Nb, Mo, Ru, Rh, Pd, In, Sn, Cs, Ba, La and Ce.

[0032] In some embodiments, the emulsifier includes at least one of higher fatty acid salt, higher fatty alcohol sulfate, sulfonate, quaternary ammonium salt, alkyl phenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyhydric alcohol oleate, polyether, polyvinyl alcohol, hydroxyethyl cellulose and dimethicone.

[0033] In some embodiments, the difference between the normal temperature boiling point of the first solvent and the normal temperature boiling point of the second solvent is greater than or equal to 5℃.

[0034] In the embodiments of the present application, the difference between the normal temperature boiling point of the first solvent and the normal temperature boiling point of the second solvent is not less than 5℃. In the micro-explosion process, the boiling point of the inner liquid in the emulsion is lower than that of the outer liquid. The inner liquid is preferentially vaporized at high temperature, and the generated gas cuts the outer liquid into small droplets, thereby achieving the intensification of the reaction process. If the boiling points of the inner and outer liquids are too small, they will vaporize at the same time at high temperature, which will increase the difficulty of micro-explosion.

[0035] In some embodiments, the first solvent includes at least one of hydrocarbon solvent, aprotic solvent, protic solvent and inorganic solvent, and the second solvent is inorganic solvent.

[0036] In some embodiments, the hydrocarbon solvent includes at least one of toluene, xylene, n-heptane, n-decane, n-hexadecane, gasoline, diesel and kerosene, the aprotic solvent includes at least one of methyl benzoate, ethyl benzoate, tetrahydrofuran, pyridine, dichloromethane, bromobenzene, acetone, diethyl ether, the protic solvent includes at least one of diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol, ethylene glycol, and the inorganic solvent includes water.

[0037] In some embodiments, the first solvent and the second solvent are not completely miscible.

[0038] In some embodiments, in step (1), the content of each component in the first solution is 0-50% of the first metal compound, 0-5% of the emulsifier, and 0-100% of the first solvent, by mass percentage; in step (2), the content of each component in the first solution is 0-50% of the second metal compound and 0-100% of the second solvent, by mass percentage.

[0039] In some embodiments, in step (3), the combustion gas used in the combustion process is air or oxygen. The temperature of the combustion can be controlled between 600-2000°C.

[0040] In a second aspect, the embodiments of the present application provide an application of the preparation method of the ultrafine powder material in the preparation of catalysts, battery electrodes and solid-state electrolytes. The ultrafine powder material prepared by the preparation method provided by the present application can be controlled between microns and nanometers in particle size, has the characteristics of small particle size, large specific surface area and good dispersity. Moreover, various morphologies including polyhedral structures with exposed high-index crystal faces, solid structures, hollow structures and core-shell structures can be controlled, and thus the ultrafine powder material can be used to prepare high-performance hydrogenation catalysts, battery electrodes and solid-state electrolytes.

[0041] The following are specific preparation embodiments related to the above content of the present disclosure. It needs to be made clear that the following embodiments are only for illustrating the preparation method of the ultrafine powder material and the application thereof disclosed above, and the specific embodiments and parameters used are only one or several methods among the numerous processes and methods disclosed above. Those skilled in the art can use other parameters to prepare the ultrafine powder material according to the above method without departing from the core spirit disclosed by the present application.

[0042] Embodiment 1

[0043] The present embodiment provides a CO2 hydrogenation catalyst, which is prepared by the preparation method of the ultrafine powder material, and the specific preparation steps are as follows:

[0044] (1) ferrocene, SPAN80, xylene (boiling point 138℃) were uniformly mixed according to the mass ratio of 5:1:100 to prepare a first solution;

[0045] (2) sodium nitrate and chromium nitrate were uniformly mixed according to the molar ratio of 1:1, and then dissolved in water (boiling point 100℃) to obtain a second solution with a concentration of 1 mol / L;

[0046] (3) the first solution and the second solution were uniformly mixed, and the mixture was emulsified to obtain a mixed emulsion; the obtained mixed emulsion was added to a spray combustion device, and the atomized emulsion droplets entered the combustion chamber for combustion; the flow rate of the emulsion was controlled to be 3 mL / min, the flow rate of oxygen was 8 L / min, the combustion atmosphere was oxygen, and after the combustion was completed, the mixture was naturally cooled to room temperature; the obtained ultrafine powder material was a CO2 hydrogenation catalyst.

[0047] Example 2

[0048] The present example provides a CO2 hydrogenation catalyst, which is prepared by the preparation method of an ultrafine powder material, and the specific preparation steps are as follows:

[0049] (1) ferrocene, SPAN80, xylene (boiling point 138℃) were uniformly mixed according to the mass ratio of 5:1:100 to prepare a first solution;

[0050] (2) sodium nitrate and copper nitrate were uniformly mixed according to the molar ratio of 1:1, and then dissolved in water (boiling point 100℃) to obtain a second solution with a concentration of 1 mol / L;

[0051] (3) the first solution and the second solution were uniformly mixed, and the mixture was emulsified to obtain a mixed emulsion; the obtained mixed emulsion was added to a spray combustion device, and the atomized emulsion droplets entered the combustion chamber for combustion; the flow rate of the emulsion was controlled to be 3 mL / min, the flow rate of oxygen was 8 L / min, the combustion atmosphere was oxygen, and after the combustion was completed, the mixture was naturally cooled to room temperature; the obtained ultrafine powder material was a CO2 hydrogenation catalyst.

[0052] Example 3

[0053] The present example provides a CO2 hydrogenation catalyst, which is prepared by the preparation method of an ultrafine powder material, and the specific preparation steps are as follows:

[0054] (1) ferrocene, SPAN80, xylene (boiling point 138℃) were uniformly mixed according to the mass ratio of 5:1:100 to prepare a first solution;

[0055] (2) Sodium nitrate and zinc nitrate were uniformly mixed in a molar ratio of 1:1 and dissolved in water (boiling point 100°C) to obtain a second solution with a concentration of 1 mol / L;

[0056] (3) The first solution and the second solution were uniformly mixed, and the mixture was emulsified to obtain a mixed emulsion. The obtained mixed emulsion was added to a spray combustion device, and the emulsion droplets after atomization entered a combustion chamber for combustion. The flow rate of the emulsion was controlled to be 3 mL / min, the flow rate of oxygen was controlled to be 8 L / min, and the combustion atmosphere was oxygen. After combustion, natural cooling was performed to room temperature, and the obtained ultrafine powder material was a CO2 hydrogenation catalyst.

[0057] Comparative Example 1

[0058] The present comparative example provides a CO2 hydrogenation catalyst, and the specific preparation steps of the CO2 hydrogenation catalyst are as follows: iron nitrate, sodium nitrate and chromium nitrate were uniformly mixed in a molar ratio of 10:1:1 and dissolved in water to obtain a raw material solution with a concentration of 1 mol / L. The obtained raw material solution was added to a spray combustion device, and the solution droplets after atomization entered a combustion chamber for combustion assisted by methane. The flow rate of the solution was controlled to be 5 mL / min, the flow rate of oxygen was controlled to be 8 L / min, and the combustion atmosphere was oxygen. After combustion, natural cooling was performed to room temperature, and the CO2 hydrogenation catalyst was obtained.

[0059] Test Example 1

[0060] The ultrafine powder materials obtained in Examples 1-3 and Comparative Example 1 were used as catalysts, which were placed in a fixed bed microreactor. Synthetic gas was introduced to activate the catalysts. After activation was completed, the gas was switched to a mixed gas with a volume ratio of H2 / CO2 / CO / N2. The catalytic hydrogenation reaction was carried out at 320°C, a system pressure of 1 MPa, and a gas volume per gram of catalyst per hour (GHSV) of 4800 mL·gcat -1 ·h -1 The reaction performance of each group of catalysts is shown in Table 1.

[0061] Table 1. Hydrogenation reaction performance test results of the catalysts of Examples 1-3 and Comparative Example 1

[0062]

[0063] As shown in Table 1, the performance of the CO2 hydrogenation catalysts prepared by the emulsion micro-explosion phenomenon in Examples 1-3 and Comparative Example 1 is significantly different. The CO2 conversion rate increased from 40% to 44.1%, the selectivity of CH4 with low added value decreased from 33% to 9%, and the selectivity of C5 +The selectivity of the component is increased from 22% to 65%. Compared with Comparative Example 1, the catalyst prepared by the micro-explosion flame spray pyrolysis process can greatly improve the chain growth ability of the CO2 hydrogenation catalyst, which is helpful to the generation of high-value-added long carbon chain products, and effectively balances high CO2 conversion rate and high long-chain hydrocarbon selectivity.

[0064] Example 4

[0065] The embodiment provides a nickel-cobalt-lithium manganate positive electrode material, which is prepared by using a superfine powder material preparation method, and the specific preparation steps are as follows:

[0066] (1) according to the molar ratio 2:5:3:0.01:10, acetylacetone nickel, acetylacetone cobalt, acetylacetone manganese, alkylphenol polyoxyethylene ether, dimethylbenzene (boiling point 138 DEG C) are uniformly mixed to prepare a first solution;

[0067] (2) lithium carbonate is dissolved in water (boiling point 100 DEG C) to obtain a second solution with a concentration of 1mol / L;

[0068] (3) the first solution and the second solution are uniformly mixed, and the mixed solution is emulsified to obtain an emulsion, the obtained emulsion is added to a spray combustion device, the atomized emulsion droplets enter the combustion chamber for combustion, the emulsion flow is controlled to be 2mL / min, the oxygen flow is 8L / min, the combustion atmosphere is oxygen, after combustion, natural cooling is carried out to room temperature, and the obtained superfine powder material is the nickel-cobalt-lithium manganate positive electrode material.

[0069] Example 5

[0070] The embodiment provides a nickel-cobalt-lithium manganate positive electrode material, which is prepared by using a superfine powder material preparation method, and the specific preparation steps are as follows:

[0071] (1) according to the molar ratio 2:6:2:0.01:0.01:10, acetylacetone nickel, acetylacetone cobalt, acetylacetone manganese, alkylphenol polyoxyethylene ether, SPAN80, n-hexadecane (boiling point 287 DEG C) are uniformly mixed to prepare a first solution;

[0072] (2) lithium carbonate is dissolved in water (boiling point 100 DEG C) to obtain a second solution with a concentration of 1mol / L;

[0073] (3) the first solution and the second solution are uniformly mixed, and the mixed solution is emulsified to obtain an emulsion, the obtained emulsion is added to a spray combustion device, the atomized emulsion droplets enter the combustion chamber for combustion, the emulsion flow is controlled to be 2mL / min, the oxygen flow is 8L / min, the combustion atmosphere is oxygen, after combustion, natural cooling is carried out to room temperature, and the obtained superfine powder material is the nickel-cobalt-lithium manganate positive electrode material.

[0074] Example 6

[0075] The embodiment provides a nickel cobalt lithium manganate positive electrode material, which is prepared by using a preparation method of superfine powder material, and the specific preparation steps are as follows:

[0076] (1) according to the molar ratio 2:6:2:0.01:0.01:10, acetylacetone nickel, acetylacetone cobalt, acetylacetone manganese, alkylphenol polyoxyethylene ether, SPAN80, methyl benzoate (boiling point 198℃) are uniformly mixed to prepare a first solution;

[0077] (2) lithium carbonate is dissolved in water (boiling point 100℃) to obtain a second solution with a concentration of 1 mol / L;

[0078] (3) the first solution and the second solution are uniformly mixed, and the mixture is emulsified to obtain an emulsion, the obtained emulsion is added to a spray combustion device, the emulsion droplets after atomization enter the combustion chamber for combustion, the emulsion flow is controlled at 2 mL / min, the oxygen flow is 8 L / min, the combustion atmosphere is oxygen, after the combustion is completed, it is naturally cooled to room temperature, and the obtained superfine powder material is the nickel cobalt lithium manganate positive electrode material.

[0079] Comparative Example 2

[0080] The comparative example provides a nickel cobalt lithium manganate positive electrode material, and the specific preparation steps of the nickel cobalt lithium manganate positive electrode material are as follows: according to the molar ratio 2:6:2:10, nickel nitrate, cobalt nitrate, manganese nitrate and lithium nitrate are uniformly mixed, then dissolved in 50% ethanol solution to prepare a solution with a concentration of 1 mol / L, the obtained solution is added to a spray combustion device, the emulsion droplets after atomization enter the combustion chamber for combustion, the emulsion flow is controlled at 2 mL / min, the oxygen flow is 8 L / min, the combustion atmosphere is oxygen, after the combustion is completed, it is naturally cooled to room temperature, and the nickel cobalt lithium manganate positive electrode material is obtained.

[0081] Test Example 2

[0082] The powder materials obtained in examples 4-6 and comparative example 2 are used as positive electrode materials, acetylene black is used as a conductive agent, and polyvinylidene fluoride is used as a binder, which are mixed in a mass ratio of 8:1:1, and a certain amount of organic solvent NMP is added, stirred and coated on aluminum foil to prepare positive electrode sheets. The negative electrode adopts a metal lithium sheet, and the separator is a Celgard2400 polypropylene porous film; the solvent in the electrolyte is a solution composed of EC, DMC and EMC in a mass ratio of 1:1:1, and the solute is LiPF6, and the concentration of LiPF6 is 1.0 mol / L; a 2023 type button cell is assembled in a glove box. The battery is tested for charge-discharge cycle performance, and the 0.1C and 1C discharge specific capacity is tested in the range of 2.8-4.3V cutoff voltage, and the test results of electrochemical performance are shown in Table 2.

[0083] Table 2. Electrochemical performance test results of the positive electrode materials of Examples 4-6, Comparative Example 2

[0084]

[0085]

[0086] As can be seen from Table 2, the lithium nickel cobalt manganese oxide positive electrode materials prepared by the micro-explosion flame spray combustion method of Examples 4-6 still maintain 97% of the initial capacity after 100 charge-discharge cycles, and have more excellent cycle stability, which can be attributed to the excellent structural strength, which can inhibit the side reactions caused by particle rupture due to strain during the charge-discharge process.

[0087] Example 7

[0088] The present example provides a garnet-type solid electrolyte (Li7La3Zr2O 12 , which is prepared by a preparation method of ultra-fine powder material, and the specific preparation steps are as follows:

[0089] (1) According to the mass ratio of 100:1, the first solution is prepared by uniformly mixing n-hexadecane (boiling point 287℃) and SPAN80;

[0090] (2) According to the molar ratio of 7:3:2, the second solution with a concentration of 1 mol / L is prepared by uniformly mixing lithium nitrate, lanthanum nitrate and zirconium nitrate and dissolving in water (boiling point 100℃);

[0091] (3) After the first solution and the second solution are uniformly mixed, the mixture is emulsified to obtain an emulsion, and the obtained emulsion is added to a spray combustion device, and the emulsion droplets after atomization enter the combustion chamber for combustion, the emulsion flow rate is controlled at 5 mL / min, the oxygen flow rate is 8 L / min, the combustion atmosphere is oxygen, and after the combustion is completed, it is naturally cooled to room temperature. The obtained ultra-fine powder material is a garnet-type solid electrolyte (Li7La3Zr2O 12 ).

[0092] Example 8

[0093] The present example provides a garnet-type solid electrolyte (Li 6.5 La3Zr 1.5 Ta 0.5 O 12 , which is prepared by a preparation method of ultra-fine powder material, and the specific preparation steps are as follows:

[0094] (1) according to the mass ratio 100:2:1, methyl benzoate (boiling point 198℃), pentachloride, P135 emulsifier are uniformly mixed to prepare a first solution;

[0095] (2) according to the molar ratio 6.5:3:1.5, lithium nitrate, lanthanum nitrate, zirconium nitrate are uniformly mixed and dissolved in water (boiling point 100℃) to prepare a second solution with a concentration of 1 mol / L;

[0096] (3) the first solution and the second solution are uniformly mixed, and the mixture is emulsified to prepare an emulsion. The obtained emulsion is added to a spray combustion device. The atomized emulsion droplets enter the combustion chamber for combustion. The emulsion flow rate is controlled at 5 mL / min, the air flow rate is 16 L / min, the combustion atmosphere is air, and after combustion, the system is naturally cooled to room temperature. The obtained ultrafine powder material is a garnet solid electrolyte (Li 6.5 La3Zr 1.5 Ta 0.5 O 12 )。

[0097] Example 9

[0098] This example provides a garnet solid electrolyte (Li 6.2 La3Zr 1.6 W 0.4 O 12 ), which is prepared by an ultrafine powder material preparation method. The specific preparation steps are as follows:

[0099] (1) according to the mass ratio 100:1, n-hexadecane (boiling point 287℃) and SPAN80 are uniformly mixed to prepare a first solution;

[0100] (2) according to the molar ratio 5.4:3:1.6:0.4, lithium nitrate, lanthanum nitrate, zirconium nitrate, and lithium tungstate are uniformly mixed and dissolved in water (boiling point 100℃) to prepare a second solution with a concentration of 1 mol / L;

[0101] (3) the first solution and the second solution are uniformly mixed, and the mixture is emulsified to prepare an emulsion. The obtained emulsion is added to a spray combustion device. The atomized emulsion droplets enter the combustion chamber for combustion. The emulsion flow rate is controlled at 5 mL / min, the oxygen flow rate is 8 L / min, the combustion atmosphere is oxygen, and after combustion, the system is naturally cooled to room temperature. The obtained ultrafine powder material is a garnet solid electrolyte (Li 6.2 La3Zr 1.6 W 0.4 O 12 )。

[0102] Comparative Example 3

[0103] The comparative example provides a garnet-type solid electrolyte (Li7La3Zr2O 12 ), and the specific preparation steps are as follows: lithium nitrate, lanthanum nitrate, and zirconium nitrate with a molar ratio of 7:3:2 are uniformly mixed and dissolved in a 50% ethanol aqueous solution to obtain a solution with a concentration of 1 mol / L; the obtained solution is added to a spray combustion device, and the emulsion droplets after atomization enter the combustion chamber for combustion, the emulsion flow is controlled at 5 mL / min, the oxygen flow is 8 L / min, the combustion atmosphere is oxygen, and after the combustion is completed, the natural cooling is performed to room temperature to obtain the garnet-type solid electrolyte (Li7La3Zr2O 12 )。

[0104] Test Example 3

[0105] The powder materials prepared in Examples 7-9 and Comparative Example 3 are added to a mold for tablet forming under a pressure of 120 Mpa, and are polished by polishing with a metallographic sandpaper, and then an Au / SSE / Au battery is constructed by double-sided gold spraying, and the ionic conductivity and electronic conductivity are tested at 60°C, and the test results are shown in Table 3.

[0106] Table 3. Electrochemical performance test results of solid electrolytes of Examples 7-9 and Comparative Example 3

[0107]

[0108] As can be seen from Table 3, there are significant differences in the ionic conductivity performance of the solid electrolytes prepared by different methods. The ionic conductivity performance of the solid electrolyte prepared by the micro-explosion flame spraying method can be improved by more than 100% compared with the traditional spray combustion method without using the micro-explosion method, and the performance can be further improved to nearly 500% by doping other metal ions.

[0109] Each technical feature of the above-described examples can be combined arbitrarily, and in order to make the description simple, all possible combinations of each technical feature in the above-described examples are not described, however, as long as the combination of these technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0110] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a more specific and detailed manner, but should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the scope of the present application. It should be understood that the technical solutions obtained by logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application by those skilled in the art are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims, and the description can be used to explain the content of the claims.

Claims

1. A method for preparing an ultrafine powder material, characterized in that, Includes the following steps: (1) Dissolve the first metal compound and the emulsifier in the first solvent to obtain the first solution; (2) Dissolve the second metal compound in the second solvent to obtain a second solution, wherein the difference between the room temperature boiling point of the first solvent and the room temperature boiling point of the second solvent is greater than or equal to 5°C, and the first solvent and the second solvent are not completely miscible; (3) The first solution and the second solution are mixed to obtain a mixed emulsion, and the mixed emulsion is atomized. The resulting atomized droplets are burned at high temperature to obtain the ultrafine powder material. During the micro-explosion process, the boiling point of the inner liquid in the emulsion is lower than that of the outer liquid. The particle size of the ultrafine powder material can be controlled between micrometers and nanometers. The morphology of the ultrafine powder material includes a polyhedral structure with exposed high index crystal planes.

2. The method for preparing ultrafine powder materials as described in claim 1, characterized in that, The first metal compound is different from the second metal compound, and the first metal compound and the second metal compound include at least one of the following: halide, carbonate, sulfate, hydroxide, organic salt and metallocene compound of metal element.

3. The method for preparing ultrafine powder materials as described in claim 2, characterized in that, The metallic element includes at least one selected from Li, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Zr, Nb, Mo, Ru, Rh, Pd, In, Sn, Cs, Ba, La, and Ce.

4. The method for preparing ultrafine powder materials as described in claim 1, characterized in that, The emulsifier includes at least one of the following: higher fatty acid salts, higher fatty alcohol sulfates, sulfonates, quaternary ammonium salts, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyol oleate esters, polyethers, polyvinyl alcohol, hydroxyethyl cellulose, and polydimethylsiloxane.

5. The method for preparing ultrafine powder materials as described in claim 1, characterized in that, The second solvent is an inorganic solvent.

6. The method for preparing ultrafine powder materials as described in claim 5, characterized in that, The first solvent includes at least one of toluene, xylene, n-heptane, n-decane, n-hexadecane, gasoline, diesel, kerosene, methyl benzoate, ethyl benzoate, tetrahydrofuran, pyridine, dichloromethane, bromobenzene, acetone, diethyl ether, diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol, and ethylene glycol, and the inorganic solvent includes water.

7. The method for preparing ultrafine powder materials as described in claim 1, characterized in that, In step (3), the combustion-supporting gas used in the combustion process is air or oxygen.

8. The application of the method for preparing ultrafine powder materials according to any one of claims 1-7 in the preparation of catalysts, battery electrodes and solid electrolytes.

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