Method for preparing doped oxide-based solid electrolyte powder

Abstract

The invention relates to the technical field of solid electrolyte material preparation, and discloses a method for preparing doped oxide-based solid electrolyte powder, and the method comprises the following steps: dissolving a titanium source substance, an aluminum source substance, a lithium source substance and a dopant source substance in one or a mixed solvent of two of ethanol, propanol and isopropanol to form a solution A; dissolving a phosphorus source substance, a lithium source substance and a dopant source substance in one or a mixed solvent of two of purified water and ethanol to form a solution B; under the stirring condition in a reaction kettle, dropwise adding the solution A into the solution B, and continuously stirring after dropwise adding to obtain a liquid precursor. Atom-level and molecular-level mixing dispersion of the oxide-based solid electrolyte raw materials in a liquid phase is realized, and compared with the characteristic that only macromixing can be realized in a ball milling method, the preparation method has the advantages that the preparation process is simple, and the cost is low. The uniformity of each component in the material can be obviously improved, so that the performance of the final material is improved.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte material preparation technology, and more particularly to a method for preparing doped oxide-based solid electrolyte powder. Background Technology

[0002] Lithium-ion batteries have wide applications in energy storage, and all-solid-state lithium-ion batteries, due to their advantages such as high safety and high energy density, have become an important direction for current research and industrialization. Solid-state electrolyte materials are a key component of all-solid-state lithium-ion batteries, and their performance directly affects the overall performance and lifespan of the battery. Furthermore, solid-state electrolyte materials can also be used in fields such as sensors; therefore, the preparation of high-performance oxide-based solid-state electrolyte materials is of great significance. Existing methods for preparing oxide-based solid-state electrolytes mainly fall into two categories. One is the ball milling method, which involves mixing solid raw materials, ball milling them for a long time, and then calcining them at high temperatures to obtain the solid electrolyte. The other is the sol-gel method, which is a wet chemical route, involving the preparation of a sol and its conversion into a gel, followed by drying and calcination to obtain the oxide solid-state electrolyte. However, both of these existing preparation methods have certain shortcomings. The ball milling method is time-consuming and energy-intensive, and it is difficult to achieve atomic or molecular-level dispersion between components, resulting in lower product performance. At the same time, the particle size prepared by the ball milling method is usually in the micrometer range, making it difficult to achieve nanometer-level dispersion. Although the sol-gel method is a wet chemical method, its preparation process is complex, lengthy, and costly, which limits its application in industrial production. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and to propose a method for preparing doped oxide-based solid electrolyte powder. To achieve the above objective, this invention adopts the following technical solution: A method for preparing doped oxide-based solid electrolyte powder includes the following steps: Step 1: Dissolve the titanium source material, aluminum source material, lithium source material, and dopant source material in one or a mixture of two solvents, namely ethanol, propanol, and isopropanol, to form solution A. The molar ratio of each component in solution A satisfies: Li:Al:Ti:M=(1+x):xy:(2-x):y; where M is the dopant element corresponding to the dopant source material, 1≥x≥0.3, y=0-0.2; Step 2: Dissolve the phosphorus source material, lithium source material, and dopant source material in one or a mixture of two solvents, such as pure water and ethanol, to form solution B. The concentration of phosphorus source material in solution B is 2.0-12.0 wt%, the concentration of lithium source material is 0-5 wt%, and the concentration of dopant material is 0.01-0.5%. Step 3: Under stirring conditions in the reaction vessel, solution A is added dropwise to solution B. After the addition is complete, stirring continues to obtain the liquid precursor. Step 4: Spray dry the liquid precursor obtained in Step 3 to obtain dry powder material; Step 5: After calcining the dry powder material prepared in Step 4, oxide-based doped nano solid electrolyte powder is obtained.

[0004] Preferably, in step 1, the concentration of solution A is 2.0-15.0 wt%.

[0005] Preferably, in step 1, the titanium source material includes one or more of ethyl titanate, propyl titanate, butyl titanate, titanium tetrachloride, and titanium oxysulfate. Aluminum source materials include one or more of aluminum nitrate, aluminum acetate, and aluminum sulfate. Lithium source materials include one or more of lithium acetate, lithium hydroxide, and lithium nitrate; The dopant source material includes one or more of magnesium hydroxide, magnesium nitrate, ammonium fluoride, and hydrofluoric acid.

[0006] Preferably, in step 2, the phosphorus source includes one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and phosphoric acid; Lithium source materials include one or more of lithium hydroxide, lithium carbonate, lithium nitrate, and lithium acetate; The dopant source material includes one or more of magnesium hydroxide, magnesium nitrate, ammonium fluoride, and hydrofluoric acid.

[0007] Preferably, in step 3, the reaction temperature is 0-5℃, and the stirring time continues for 1-5 hours after the addition is completed.

[0008] Preferably, in step 3, the molar ratio of each component in the liquid precursor satisfies: Li:Al:Ti:P:M=(1+x):(xy):1.7:3:y, where M is the dopant element corresponding to the dopant source material, 1≥x≥0.3, y=0-0.2.

[0009] Preferably, in step 4, the spray drying temperature is 160-220℃ and the moisture content of the dry powder material is 3-5%.

[0010] Preferably, in step 5, the roasting temperature is 600-900℃ and the roasting time is 3-5 hours.

[0011] The beneficial effects of this invention are as follows: This invention employs a wet chemical preparation route using spray drying technology, achieving atomic and molecular-level mixing and dispersion of oxide-based solid electrolyte raw materials in the liquid phase. Compared to ball milling, which only achieves macroscopic mixing, this method significantly improves the uniformity of components within the material, thereby enhancing the final material's performance. Simultaneously, this method avoids the complex, lengthy, and costly processes of the sol-gel method, eliminating the need for gel formation and post-processing steps, resulting in a simpler process. The spray drying process in this invention is fast, energy-efficient, requires minimal equipment investment, and eliminates the need for complex operations such as filtration. The preparation process generates no waste gas, wastewater, or solid waste emissions, making it more environmentally friendly and conducive to industrial application. Furthermore, by controlling the spray drying process, the powder particle size can be controlled, facilitating the acquisition of nanoscale solid electrolyte powder. By doping and altering the electrolyte composition, this invention can significantly improve the material's ionic conductivity and other properties. Doping at the atomic and molecular level results in a more rational internal structure, enhancing material performance. Comparative test results show that the conductivity of the material prepared by this invention is significantly superior to that prepared by ball milling, demonstrating the significant performance advantages of this technical solution. The present invention features a simple process route and short flow, which helps reduce production costs. It also boasts low energy consumption and minimal equipment requirements, making it suitable for large-scale production. In summary, the present invention combines significant advantages such as low cost, high performance, environmental friendliness, and process controllability. Attached Figure Description

[0012] Figure 1 Photograph of the doped oxide-based solid electrolyte powder prepared in Example 1 of this invention; Figure 2 The image shown is an electron microscope image of the doped oxide-based solid electrolyte powder prepared in Example 1 of this invention. Figure 3 The XRD patterns of the doped oxide-based solid electrolyte powders obtained after calcination at different temperatures in the preparation method of this invention are shown. Figure 4 The image shows the EIS spectrum of the doped oxide-based solid electrolyte powder prepared in Example 1 of this invention. Figure 5 This invention provides a flowchart of a method for preparing doped oxide-based solid electrolyte powder. Detailed Implementation

[0013] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below, but this should not be construed as limiting the scope of implementation of this invention. Unless otherwise specified, the methods used in this invention are conventional methods in this technical field. In this invention, materials, reagents, or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0014] The specific implementation of the present invention will be described in detail below with reference to specific embodiments. Embodiment 1: Ethyl titanate, aluminum nitrate, lithium hydroxide, and magnesium hydroxide were dissolved in ethanol to form solution A, which had a concentration of 2.0 wt% and a molar ratio of Li:Al:Ti:M of 2:0.9:1:0.1. Ammonium dihydrogen phosphate, lithium hydroxide, and magnesium nitrate were dissolved in pure water to form solution B. The concentration of phosphorus source material in solution B was 2.0 wt%, the concentration of lithium source material was 0.1 wt%, and the concentration of dopant material was 0.01%. In a stainless steel reactor at 0-5℃ with stirring, solution A is added dropwise to solution B. After the addition is complete, stirring is continued for 1-5 hours to obtain a liquid precursor. The molar ratio of each component in the liquid precursor satisfies: Li:Al:Ti:P:M=2:0.9:1.7:3:0.1, where M is the dopant element corresponding to the dopant source material. The liquid precursor is spray-dried at a temperature of 160-220℃ to obtain a dry powder material with a moisture content of 3-5%. After calcining the dry powder material at 900℃ for 3-5 hours, oxide-based doped nano solid electrolyte powder is obtained.

[0015] Example 2: Ethyl titanate, titanium tetrachloride, aluminum nitrate, aluminum acetate, lithium hydroxide, lithium nitrate, magnesium nitrate, and magnesium hydroxide are dissolved in ethanol to form solution A, which has a concentration of 15.0 wt%. The molar ratio of each component in solution A satisfies the following condition: Li:Al:Ti:M = 1.3:0.1:1.7:0.2. Ammonium dihydrogen phosphate, phosphoric acid, lithium hydroxide, lithium acetate, ammonium fluoride, and magnesium nitrate were dissolved in pure water to form solution B. The concentration of phosphorus source material in solution B was 12.0 wt%, the concentration of lithium source material was 5 wt%, and the concentration of dopant material was 0.5%. In a stainless steel reactor at 0-5℃ under stirring conditions, solution A is added dropwise to solution B. After the addition is completed, stirring is continued for 1-5 hours to obtain a liquid precursor. The molar ratio of each component in the liquid precursor satisfies: Li:Al:Ti:P:M=1.3:0.1:1.7:3:0.2, where M is the dopant element corresponding to the dopant source material. The liquid precursor is spray-dried at a temperature of 160-220℃ to obtain a dry powder material with a moisture content of 3-5%. After calcining the dry powder material at 600℃ for 3-5 hours, oxide-based doped nano solid electrolyte powder is obtained.

[0016] Example 3: The difference from Example 1 is that in this example, the dry powder material obtained in step 4 is calcined at 750°C for 3-5 hours. After calcination, oxide-based doped nano solid electrolyte powder is obtained.

[0017] Example 4: The difference from Example 1 is that in this example, the dry powder material obtained in step 4 is calcined at 800°C for 3-5 hours. After calcination, oxide-based doped nano solid electrolyte powder is obtained.

[0018] Example 5: The difference from Example 1 is that in this example, the dry powder material obtained in step 4 is calcined at 850°C for 3-5 hours. After calcination, oxide-based doped nano solid electrolyte powder is obtained.

[0019] Test Example 1: The oxide-based doped nano-solid electrolyte powders prepared in Examples 1 and 3 to 5 were pressed into tablets and sintered at 900°C. After sintering, the sample surface was polished to remove uneven areas, and its thickness was measured. Subsequently, a layer of conductive silver paste was coated on the sample surface, a platinum electrode was attached, and AC impedance spectroscopy was performed on the sample using an electrochemical workstation. The test data was simulated and calculated using the equivalent circuit method to obtain the conductivity of the material. The test results are shown in Table 1: Temperature (°C) Electrical conductivity (mS / cm) Example 3 750 0.43 Example 4 800 0.45 Example 5 850 0.33 Example 1 900 0.33 Comparative Example 1: Lithium carbonate, aluminum hydroxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the molar ratio of Li:Al:Ti:P = 1.3:0.3:1.7:3. Ethanol was added as a grinding aid and the mixture was ball-milled for 12 hours. Then, it was vacuum dried and crushed. The resulting powder was calcined at 800°C for 3 hours. The ionic conductivity was measured to be 0.23 mS / cm according to the test method of Test Example 1 above.

[0020] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing doped oxide-based solid electrolyte powder, characterized in that, Includes the following steps: Step 1: Dissolve the titanium source material, aluminum source material, lithium source material, and dopant source material in one or a mixture of two solvents, namely ethanol, propanol, and isopropanol, to form solution A. The molar ratio of each component in solution A satisfies: Li:Al:Ti:M=(1+x):xy:(2-x):y; where M is the dopant element corresponding to the dopant source material, 1≥x≥0.3, y=0-0.2; Step 2: Dissolve the phosphorus source material, lithium source material, and dopant source material in one or a mixture of two solvents, such as pure water and ethanol, to form solution B. The concentration of phosphorus source material in solution B is 2.0-12.0 wt%, the concentration of lithium source material is 0-5 wt%, and the concentration of dopant material is 0.01-0.5%. Step 3: Under stirring conditions in the reaction vessel, solution A is added dropwise to solution B. After the addition is complete, stirring continues to obtain the liquid precursor. Step 4: Spray dry the liquid precursor obtained in Step 3 to obtain dry powder material; Step 5: After calcining the dry powder material prepared in Step 4, oxide-based doped nano solid electrolyte powder is obtained.

2. The method for preparing doped oxide-based solid electrolyte powder according to claim 1, characterized in that, In step 1, the concentration of solution A is 2.0-15.0 wt%.

3. The method for preparing doped oxide-based solid electrolyte powder according to claim 2, characterized in that, In step 1, the titanium source material includes one or more of ethyl titanate, propyl titanate, butyl titanate, titanium tetrachloride, and titanium oxysulfate. Aluminum source materials include one or more of aluminum nitrate, aluminum acetate, and aluminum sulfate. Lithium source materials include one or more of lithium acetate, lithium hydroxide, and lithium nitrate; The dopant source material includes one or more of magnesium hydroxide, magnesium nitrate, ammonium fluoride, and hydrofluoric acid.

4. The method for preparing doped oxide-based solid electrolyte powder according to claim 1, characterized in that, In step 2, the phosphorus source material includes one or more of the following: ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and phosphoric acid. Lithium source materials include one or more of lithium hydroxide, lithium carbonate, lithium nitrate, and lithium acetate; The dopant source material includes one or more of magnesium hydroxide, magnesium nitrate, ammonium fluoride, and hydrofluoric acid.

5. The method for preparing doped oxide-based solid electrolyte powder according to claim 1, characterized in that, In step 3, the reaction temperature is 0-5℃, and the stirring time is 1-5 hours after the addition is completed.

6. The method for preparing doped oxide-based solid electrolyte powder according to claim 5, characterized in that, In step 3, the molar ratio of each component in the liquid precursor satisfies: Li:Al:Ti:P:M=(1+x):(xy):1.7:3:y, where M is the dopant element corresponding to the dopant source material, 1≥x≥0.3, y=0-0.

2.

7. The method for preparing doped oxide-based solid electrolyte powder according to claim 1, characterized in that, In step 4, the spray drying temperature is 160-220℃, and the moisture content of the dry powder material is 3-5%.

8. The method for preparing doped oxide-based solid electrolyte powder according to claim 1, characterized in that, In step 5, the roasting temperature is 600-900℃ and the roasting time is 3-5 hours.

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