Preparation method and application of ultrafine powder material

Abstract

The invention discloses a preparation method and application of an ultrafine powder material. By means of the micro-explosion technology, the technology for preparing the granular material through the spray combustion method is optimized to overcome the defects that the spray combustion method is large in solvent atomization difficulty, small in available precursor number and the like, so that the powder material processing means are improved and perfected, and the performance of the obtained powder material product is improved. According to the preparation method of the superfine powder material, the preparation process is simple, the steps are few, synthesis is easy, and 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-added-value products.

Description

Technical Field

[0001] The present application relates to the technical field of high-performance materials, and in particular to a method for preparing an ultrafine powder material and its application. Background Art

[0002] According to the difference in phase formation or grain structure length, ultrafine powder materials can be divided into micron materials (1-5μm), submicron materials (100nm-1μm) and nanomaterials (less than 100nm). Based on their high mechanical strength, extraordinary magnetic resistance and thermal conductivity and electrical properties, combined with the self-assembly effect, small size, quantum and surface effects of nanomaterials themselves, ultrafine powder materials can be widely used in microelectronic components, hydrogen storage materials, capacitor materials, photoconductive materials, and biosensor materials.

[0003] With the goal of regulating the geometric parameters, spatial distribution parameters and volume fraction of each microscopic unit in the system, by controlling the spatial restriction conditions, reaction kinetic factors, thermodynamic factors and other preparation conditions, the preparation of ultrafine powder materials can be divided into solid phase method, gas phase method, liquid phase method and spray combustion method. Among them, the solid phase method is a traditional method for preparing materials. The precursor is generated by double decomposition reaction, and then the ultrafine powder is obtained by washing, grinding, calcining and grinding. The overall process of the solid phase method is simple, the reaction conditions are easy to control, and the product yield is high and the cost is low. However, there are disadvantages of uneven particle size and easy agglomeration. The gas phase method represented by chemical vapor deposition generates materials through chemical reactions between gaseous raw materials. The prepared powder has high purity, small particle size, is not easy to agglomerate, and the product components are controllable, but this method has strict requirements on the composition of raw materials and is less applicable than other preparation methods. According to the different preparation processes, the liquid phase method can be further divided into precipitation method, gel method, hydrothermal method and solvent thermal method. The composition, shape and size of the product in the specific preparation process are easy to control, and materials with complex components can also prepare powder materials with high chemical uniformity. However, impurities such as anions are easily introduced during the production process, resulting in low product purity. As a new method that integrates solution combustion method and spray pyrolysis method, spray pyrolysis method can prepare 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. However, flame spray pyrolysis method generally uses liquid phase feeding, and the organic solvent used is difficult to atomize. In addition, liquid phase feeding requires that the metal precursors in the reaction process have a high solubility in organic solutions, which is costly and has limited choices.

[0004] Therefore, it is necessary to improve and perfect the existing ultrafine powder material preparation method to improve the product performance of ultrafine powder materials. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a method for preparing an ultrafine powder material and its application.

[0006] In a first aspect, the present invention provides a method for preparing an ultrafine 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) The first solution and the second solution are mixed to obtain a mixed emulsion, and the mixed emulsion is atomized to obtain the ultrafine powder material after the obtained atomized droplets are burned at high temperature.

[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 include at least one of halides, carbonates, sulfates, hydroxides, organic salts, silicates and metallocene compounds of metal elements.

[0011] In some embodiments, 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.

[0012] In some embodiments, the emulsifier includes at least one of higher fatty acid salts, higher fatty alcohol sulfates, sulfonates, quaternary ammonium salts, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyol oleates, polyethers, polyvinyl alcohol, hydroxyethyl cellulose, and polydimethylsiloxane.

[0013] 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°C.

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

[0015] 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 and ether; the protic solvent includes at least one of diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol and ethylene glycol; and the inorganic solvent includes water.

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

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

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

[0019] In a second aspect, the embodiments of the present application provide a method for preparing an ultrafine powder material and its application in preparing catalysts, battery electrodes and solid electrolytes.

[0020] It can be seen from the above technical solutions that the present application provides a new method for preparing ultrafine powder materials. By using micro-explosion technology, the process of preparing granular materials by spray combustion is optimized to improve the shortcomings of the spray combustion method, such as the difficulty of solvent atomization and the small number of available precursors, thereby improving and perfecting the powder material processing methods and improving the performance of the obtained powder material products. The method for preparing ultrafine powder materials provided in the present application has a simple preparation process, few steps, and is easy to synthesize. The prepared powder material has a small particle size, a large specific surface area, and good dispersibility, and can be further used to prepare high value-added products.

[0021] Compared with the traditional spray pyrolysis method, the ultrafine powder material preparation method proposed in this application can control a variety of morphologies including polyhedral structures with exposed high-index crystal faces, solid structures, hollow structures and core-shell structures, and effectively reduce the difficulty of solvent atomization, expand the types of metal precursors that can be used, and have a wider source of raw materials, lower production costs and better product performance. It is of great significance for improving and perfecting the processing methods of powder materials and improving the performance of related products. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of this specification, this specification will be described more comprehensively below. This specification can be implemented in many different forms without departing from the core spirit of this 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 this specification more thorough and comprehensive.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this specification belongs. The terms used herein in this specification are only for the purpose of describing specific embodiments and are not intended to limit this specification. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] Flame spray pyrolysis is a new method that combines solution combustion and spray pyrolysis. It can prepare ultrafine powders with uniform composition at a relatively low 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) Self-propagating combustion can be achieved by low-temperature ignition, releasing a large amount of heat and gas, and reaching high temperatures instantly; (2) The stoichiometric ratio of the components is accurate and the uniformity is high; (3) The process equipment is simple, and the synthesis is fast and energy-saving. Despite the above advantages, the spray pyrolysis method still has the following shortcomings: Spray pyrolysis generally uses liquid phase feeding, and the organic solvent used is difficult to atomize; in addition, liquid phase feeding requires that the metal precursors in the reaction process have a high solubility in organic solutions, which is costly and has limited choices.

[0025] "Micro-explosion" refers to the process in which an emulsion formed by a mixture of liquids with different boiling points expands rapidly in volume and quickly vaporizes into an aerosol state after being atomized and entering a high-temperature environment. The diameter of the droplets after micro-explosion is significantly reduced, and the atomization performance is greatly improved, which has excellent heat and mass transfer efficiency, can effectively enhance the mass transfer and heat transfer of the combustion process, increase the yield of combustion reaction products and improve product performance. Based on the above characteristics, the micro-explosion process is applied to the spray pyrolysis method to prepare powder materials. The water-soluble solvent used is easy to atomize and can effectively expand the types of metal precursors that can be used; in addition, compared with organic solvents, water-soluble solvents can produce a wider range of flame temperature fields during the combustion process, and can produce powder materials with more diverse structures. Compared with traditional spray pyrolysis, micro-explosion enhanced flame spray pyrolysis technology has a wider source of raw materials, lower production costs and better product performance. It is of great significance to improve and perfect the processing methods of powder materials and improve the performance of related products. However, in the current ultrafine powder material preparation process, most of them still use spray combustion as the core preparation method, and do not involve the application of micro-explosion technology to enhance the spray combustion method.

[0026] In this regard, in a first aspect, an embodiment of the present application provides a method for preparing an 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) The first solution and the second solution are mixed to obtain a mixed emulsion, and the mixed emulsion is atomized to obtain an ultrafine powder material after the atomized droplets are burned at a high temperature.

[0030] In the embodiment of the present application, the first solution, the second solution and the mixed solution are maintained in an emulsion state after being processed by emulsion. Among them, the emulsification process can adopt ultrasonic emulsification, mechanical emulsification and membrane emulsification. In addition, the mixed emulsion needs to be maintained in an emulsion state before combustion, and the emulsion is ignited and burned by atomization. The atomization process can adopt two-fluid atomization, ultrasonic atomization and pressure atomization.

[0031] In some embodiments, 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 halides, carbonates, sulfates, hydroxides, organic salts, silicates and metallocene compounds of the 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 salts, higher fatty alcohol sulfates, sulfonates, quaternary ammonium salts, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyol oleates, polyethers, polyvinyl alcohol, hydroxyethyl cellulose, and polydimethylsiloxane.

[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°C.

[0034] In the embodiment 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°C. During the micro-explosion process, the boiling point of the inner layer liquid in the emulsion is lower than that of the outer layer liquid. At high temperature, the inner layer liquid is preferentially vaporized, and the generated gas cuts the outer layer liquid into small particle size droplets, thereby strengthening the reaction process. If the boiling point difference between the inner and outer layers of liquid is too small, they are easy to vaporize at the same time at high temperature, making the micro-explosion more difficult.

[0035] In some embodiments, the first solvent includes at least one of a hydrocarbon solvent, an aprotic solvent, a protic solvent, and an inorganic solvent, and the second solvent is an 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, and ether, the protic solvent includes at least one of diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol, and ethylene glycol, and the inorganic solvent includes water.

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

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

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

[0040] On the second aspect, the embodiments of the present application provide an application of a method for preparing an ultrafine powder material in the preparation of catalysts, battery electrodes and solid electrolytes. The ultrafine powder material is prepared by the preparation method provided in the present application, and the particle size of the ultrafine powder material can be regulated between the micrometer and nanometer levels, and has the characteristics of small particle size, large specific surface area and good dispersibility. In addition, a variety of morphologies including polyhedral structures with exposed high-index crystal faces, solid structures, hollow structures and core-shell structures can also be regulated, so it can be used to prepare high-performance hydrogenation catalysts, battery electrodes and solid electrolytes.

[0041] The following are specific preparation examples involved in the above content of the present disclosure. It should be clear that the following examples are only for illustrating the preparation method and application of the ultrafine powder material disclosed above, and the specific implementation methods and parameters used therein are only one or several methods in accordance with the many processes and methods described above. Those skilled in the art can use other parameters according to the content introduced in this specification to prepare ultrafine powder materials according to the above method without deviating from the core spirit disclosed in the application.

[0042] Example 1

[0043] This embodiment provides a CO2 hydrogenation catalyst, which is prepared by a method for preparing ultrafine powder materials. The specific preparation steps are as follows:

[0044] (1) ferrocene, SPAN80, and xylene (boiling point 138° C.) were uniformly mixed in a mass ratio of 5:1:100 to prepare a first solution;

[0045] (2) mixing sodium nitrate and chromium nitrate evenly in a molar ratio of 1:1 and dissolving the mixture in water (boiling point: 100° C.) to obtain a second solution with a solubility of 1 mol / L;

[0046] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain a mixed emulsion, and the obtained mixed emulsion is added to a spray combustion device. The atomized emulsion droplets enter the combustion chamber for combustion. The emulsion flow rate is controlled to be 3 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a CO2 hydrogenation catalyst.

[0047] Example 2

[0048] This embodiment provides a CO2 hydrogenation catalyst, which is prepared by a method for preparing ultrafine powder materials. The specific preparation steps are as follows:

[0049] (1) ferrocene, SPAN80, and xylene (boiling point 138° C.) were uniformly mixed in a mass ratio of 5:1:100 to prepare a first solution;

[0050] (2) mixing sodium nitrate and copper nitrate evenly in a molar ratio of 1:1 and dissolving the mixture in water (boiling point: 100° C.) to obtain a second solution with a concentration of 1 mol / L;

[0051] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain a mixed emulsion, and the obtained mixed emulsion is added to a spray combustion device. The atomized emulsion droplets enter the combustion chamber for combustion. The emulsion flow rate is controlled to be 3 mL / min, the air flow rate is 16 L / min, and the combustion atmosphere is air. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a CO2 hydrogenation catalyst.

[0052] Example 3

[0053] This embodiment provides a CO2 hydrogenation catalyst, which is prepared by a method for preparing ultrafine powder materials. The specific preparation steps are as follows:

[0054] (1) ferrocene, SPAN80, and xylene (boiling point 138° C.) were uniformly mixed in a mass ratio of 5:1:100 to prepare a first solution;

[0055] (2) mixing sodium nitrate and zinc nitrate evenly in a molar ratio of 1:1 and dissolving the mixture in water (boiling point: 100° C.) to obtain a second solution with a concentration of 1 mol / L;

[0056] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain a mixed emulsion, and the obtained mixed emulsion is added to a spray combustion device. The atomized emulsion droplets enter the combustion chamber for combustion. The emulsion flow rate is controlled to be 3 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a CO2 hydrogenation catalyst.

[0057] Comparative Example 1

[0058] This comparative example provides a CO2 hydrogenation catalyst, and the specific preparation steps of the CO2 hydrogenation catalyst are as follows: according to the molar ratio of 10:1:1, iron nitrate, sodium nitrate and chromium nitrate are uniformly mixed and dissolved in water to obtain a raw material solution with a concentration of 1 mol / L. The obtained raw material solution is added to a spray combustion device, and the atomized solution droplets enter the combustion chamber for methane-assisted combustion, and the solution flow rate is controlled to be 5 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature to obtain a CO2 hydrogenation catalyst.

[0059] Test Example 1

[0060] The ultrafine powder materials obtained in Examples 1-3 and Comparative Example 1 were used as catalysts and placed in a fixed bed microreactor. Syngas was introduced to increase the temperature to activate the catalyst. After the activation was completed and the temperature was lowered, the gas was switched to a mixed gas with a volume ratio of H2 / CO2 / CO / N2. At 320°C and a system pressure of 1 MPa, the volume of gas flowing over each gram of catalyst per hour (GHSV) was 4800 mL gcat. -1 ·h -1 The catalytic hydrogenation reaction was carried out under the conditions of , and 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, there are significant differences in the performance of the CO2 hydrogenation catalysts prepared by using the emulsion micro-explosion phenomenon in Examples 1-3 and Comparative Example 1. The CO2 conversion rate increased from 40% to 44.1%, the low value-added CH4 selectivity decreased from 33% to 9%, and the high value-added C5 +The component selectivity 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, contribute to the generation of high value-added long carbon chain products, and effectively take into account both high CO2 conversion rate and high long-chain hydrocarbon selectivity.

[0064] Example 4

[0065] This embodiment provides a nickel-cobalt-manganese-oxide lithium positive electrode material, which is prepared by a method for preparing an ultrafine powder material. The specific preparation steps are as follows:

[0066] (1) uniformly mixing nickel acetylacetonate, cobalt acetylacetonate, manganese acetylacetonate, alkylphenol polyoxyethylene ether, and xylene (boiling point 138° C.) in a molar ratio of 2:5:3:0.01:10 to prepare a first solution;

[0067] (2) dissolving lithium carbonate in water (boiling point: 100° C.) to obtain a second solution having a concentration of 1 mol / L;

[0068] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain an emulsion, and 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 to be 2 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is the nickel cobalt manganese oxide lithium positive electrode material.

[0069] Example 5

[0070] This embodiment provides a nickel cobalt lithium manganese oxide positive electrode material, which is prepared by a method for preparing an ultrafine powder material. The specific preparation steps are as follows:

[0071] (1) nickel acetylacetonate, cobalt acetylacetonate, manganese acetylacetonate, alkylphenol polyoxyethylene ether, SPAN80, and n-hexadecane (boiling point 287° C.) are uniformly mixed in a molar ratio of 2:6:2:0.01:0.01:10 to prepare a first solution;

[0072] (2) dissolving lithium carbonate in water (boiling point: 100° C.) to obtain a second solution having a concentration of 1 mol / L;

[0073] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain an emulsion, and 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 to be 2 mL / min, the air flow rate is 16 L / min, and the combustion atmosphere is air. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is the nickel cobalt manganese oxide lithium positive electrode material.

[0074] Example 6

[0075] This embodiment provides a nickel cobalt lithium manganese oxide positive electrode material, which is prepared by a method for preparing an ultrafine powder material. The specific preparation steps are as follows:

[0076] (1) nickel acetylacetonate, cobalt acetylacetonate, manganese acetylacetonate, alkylphenol polyoxyethylene ether, SPAN80, and methyl benzoate (boiling point 198° C.) were uniformly mixed in a molar ratio of 2:6:2:0.01:0.01:10 to prepare a first solution;

[0077] (2) dissolving lithium carbonate in water (boiling point: 100° C.) to obtain a second solution having a concentration of 1 mol / L;

[0078] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain an emulsion, and 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 to be 2 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is the nickel cobalt manganese oxide lithium positive electrode material.

[0079] Comparative Example 2

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

[0081] Test Example 2

[0082] The powder material obtained in Examples 4-6 and Comparative Example 2 is used as the positive electrode material, acetylene black is used as the conductive agent, polyvinylidene fluoride is used as the binder, and they are mixed in a mass ratio of 8:1:1, and a certain amount of organic solvent NMP is added, and the mixture is coated on an aluminum foil after stirring to form a positive electrode sheet. The negative electrode uses a metal lithium sheet, and the diaphragm is a Celgard2400 polypropylene porous membrane; the solvent in the electrolyte is a solution composed of EC, DMC and EMC in a mass ratio of 1:1:1, the solute is LiPF6, and the concentration of LiPF6 is 1.0 mol / L; 2023 button cells are assembled in a glove box. The battery is tested for charge and discharge cycle performance, and the 0.1C and 1C discharge specific capacities are tested within the cut-off voltage range of 2.8-4.3V. The electrochemical performance test results are shown in Table 2.

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

[0084]

[0085]

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

[0087] Example 7

[0088] This embodiment provides a garnet-type solid electrolyte (Li7La3Zr2O 12 ), the garnet-type solid electrolyte is prepared by a method for preparing ultrafine powder materials, and the specific preparation steps are as follows:

[0089] (1) n-hexadecane (boiling point 287° C.) and SPAN80 were uniformly mixed in a mass ratio of 100:1 to prepare a first solution;

[0090] (2) mixing lithium nitrate, lanthanum nitrate and zirconium nitrate uniformly in a molar ratio of 7:3:2, and dissolving the mixture in water (boiling point: 100° C.) to prepare a second solution with a concentration of 1 mol / L;

[0091] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain an emulsion, and 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 to be 5 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a garnet-type solid electrolyte (Li7La3Zr2O 12 ).

[0092] Example 8

[0093] This embodiment provides a garnet-type solid electrolyte (Li 6.5 Ln3Z 1.5 Ta 0.5 O 12 ), the garnet-type solid electrolyte is prepared by a method for preparing ultrafine powder materials, and the specific preparation steps are as follows:

[0094] (1) Methyl benzoate (boiling point: 198° C.), tantalum pentachloride, and P135 emulsifier were uniformly mixed in a mass ratio of 100:2:1 to prepare a first solution;

[0095] (2) mixing lithium nitrate, lanthanum nitrate and zirconium nitrate uniformly at a molar ratio of 6.5:3:1.5, and dissolving the mixture in water (boiling point: 100° C.) to prepare a second solution with a concentration of 1 mol / L;

[0096] (3) After the first solution and the second solution are mixed evenly, the mixed solution is emulsified to obtain an emulsion, and 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 to be 5 mL / min, the air flow rate is 16 L / min, and the combustion atmosphere is air. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a garnet-type solid electrolyte (Li 6.5 Ln3Z 1.5 Ta 0.5 O 12 ).

[0097] Example 9

[0098] This embodiment provides a garnet-type solid electrolyte (Li 6.2 Ln3Z 1.6 W 0.4 O 12 ), the garnet-type solid electrolyte is prepared by a method for preparing ultrafine powder materials, and the specific preparation steps are as follows:

[0099] (1) n-hexadecane (boiling point 287° C.) and SPAN80 were uniformly mixed in a mass ratio of 100:1 to prepare a first solution;

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

[0101] (3) After the first solution and the second solution are evenly mixed, the mixed solution is emulsified to obtain an emulsion, and 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 to be 5 mL / min, the oxygen flow rate is 8 L / min, and the combustion atmosphere is oxygen. After the combustion is completed, it is naturally cooled to room temperature. The obtained ultrafine powder material is a garnet-type solid electrolyte (Li 6.2 Ln3Z 1.6 W 0.4 O 12 ).

[0102] Comparative Example 3

[0103] This comparative example provides a garnet-type solid electrolyte (Li7La3Zr2O 12 ), the specific preparation steps of the garnet-type solid electrolyte 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 atomized emulsion droplets enter the combustion chamber for combustion, the emulsion flow rate is controlled to be 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 to obtain a garnet-type solid electrolyte (Li7La3Zr2O 12 ).

[0104] Test Example 3

[0105] The powder materials prepared in Examples 7-9 and Comparative Example 3 were added into a mold and pressed into tablets under a pressure of 120 MPa. They were polished with metallographic sandpaper and then double-sided gold sprayed to construct Au / SSE / Au batteries. The ionic conductivity and electronic conductivity thereof were tested at 60°C. 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 solid electrolytes prepared by different methods. The ionic conductivity performance of solid electrolytes prepared by micro-explosion flame spraying can be improved by more than 100% compared with the traditional spray combustion method without micro-explosion. By doping with other metal ions, the performance can be further improved to nearly 500%.

[0109] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The above-described embodiments only express several embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. It should be understood that, on the basis of the technical solutions provided by those skilled in the art in the present application, the technical solutions obtained through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing ultrafine powder material, characterized in that: The following steps are involved: (1) dissolving a first metal compound and an emulsifier in a first solvent to obtain a first solution; (2) dissolving a second metal compound in a second solvent to obtain a second solution; (3) The first solution and the second solution are mixed to obtain a mixed emulsion, and the mixed emulsion is atomized to obtain the ultrafine powder material after the obtained atomized droplets are burned at high temperature.

2. The method for preparing ultrafine powder material according to 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 halides, carbonates, sulfates, hydroxides, organic salts, silicates and metallocene compounds of metal elements.

3. The method for preparing ultrafine powder material according to claim 2, characterized in that: 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.

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

5. The method for preparing ultrafine powder material according to claim 1, characterized in that: 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°C.

6. The method for preparing ultrafine powder material according to claim 5, characterized in that: The first solvent includes at least one of a hydrocarbon solvent, an aprotic solvent, a protic solvent and an inorganic solvent, and the second solvent is an inorganic solvent.

7. The method for preparing ultrafine powder material according to claim 6, characterized in that: 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 and ether; the protic solvent includes at least one of diethylamine, aniline, benzyl alcohol, methanol, ethanol, formic acid, octanol and ethylene glycol; and the inorganic solvent includes water.

8. The method for preparing an ultrafine powder material according to any one of claims 4 to 6, characterized in that: The first solvent and the second solvent are not completely miscible with each other.

9. The method for preparing ultrafine powder material according to claim 1, characterized in that: In step (3), the combustion-supporting gas used in the combustion process is air or oxygen.

10. Use of the method for preparing the ultrafine powder material according to any one of claims 1 to 9 in preparing catalysts, battery electrodes and solid electrolytes.

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