Method for testing particle size distribution of inorganic solid electrolyte

Abstract

The invention relates to the technical field of analysis and detection, and discloses an inorganic solid electrolyte particle size distribution testing method which comprises the following steps: (1) preparing a dispersion medium solution; (2) mixing the inorganic solid electrolyte with the dispersion medium solution to obtain a sample suspension; and (3) testing the particle size of the sample suspension through a laser diffraction method. In the scheme of the invention, the inorganic solid electrolyte suspension which is uniformly dispersed and has no sedimentation and agglomeration phenomenon can be prepared by selecting a non-toxic and stable dispersion medium, optimizing the formula of the dispersing agent and selecting proper dispersion conditions, and an ideal test result is obtained.

Description

Technical Field

[0001] This application relates to the field of analytical testing technology, and mainly to a method for testing the particle size distribution of inorganic solid electrolytes. Background Technology

[0002] With the rapid development of new energy vehicles and future intelligent mobility devices, power batteries face higher requirements in terms of energy density, cycle life, and operational safety. Currently, mainstream commercial lithium-ion batteries primarily use organic electrolytes as the lithium-ion transport medium, which poses safety hazards such as electrolyte leakage and thermal runaway. All-solid-state lithium batteries, with their high energy density, rapid charge / discharge capabilities, and excellent low-temperature performance, have innovatively solved the safety concerns of traditional liquid batteries, namely flammability and explosiveness, while also extending battery cycle life. They have now become one of the most revolutionary cutting-edge technologies in the new energy field.

[0003] Solid-state electrolytes are the core materials of solid-state batteries, and their performance directly affects the battery's performance. Solid-state electrolytes can generally be classified into three categories: inorganic solid-state electrolytes, polymer solid-state electrolytes, and solid-state composite electrolytes. In recent years, inorganic solid-state electrolyte technology has developed rapidly, mainly divided into oxide electrolytes, sulfide electrolytes, and novel halide electrolytes. From a materials engineering perspective, the synthesis process directly determines the particle morphology and size distribution of solid-state electrolytes, and these two key parameters have a decisive impact on their ion conductivity, interfacial contact performance, and mechanical strength. Through the synergistic application of laser diffraction with characterization techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), researchers can systematically analyze the structure-property relationship between particle microstructure and electrochemical performance, providing a theoretical basis for materials design.

[0004] Particle size analysis methods include sedimentation, sieving, laser diffraction, and electron microscopy. Sedimentation and sieving are slow, and the results are significantly affected by human factors, resulting in poor repeatability. While electron microscopy allows direct observation of particle morphology, its representativeness is poor. Currently, laser diffraction is the most widely used method for material particle size analysis. Laser diffraction has dry and wet modes. However, due to the significant air sensitivity of inorganic solid electrolytes, which readily react to form corrosive and toxic substances such as hydrogen sulfide and hydrogen chloride when exposed to air, the dry mode of laser diffraction is often chosen for such samples. However, dry testing has the following disadvantages: 1. Stringent hardware requirements and inconvenient operation: The air sensitivity of inorganic solid electrolytes requires the particle size analyzer to be placed inside a glove box during testing, making operation difficult. Furthermore, the components of the particle size analyzer that contact the sample require special coating treatment and a precision airflow control system. 2. Poor particle dispersibility: It is easily affected by particle agglomeration, especially fine particles (such as nanomaterials) are prone to agglomeration due to van der Waals forces or electrostatic effects, resulting in a larger measured particle size and a decrease in accuracy; 3. High difficulty in test control: Dry dispersion is not easy to control. The dispersion pressure needs to be adjusted according to the characteristics of the sample. Fragile powders are very sensitive to air pressure, and agglomerated particles require high dispersion pressure. 4. High sample volume requirement: Sufficient sample volume is required to form a stable airflow, which is not suitable for rare or precious samples; 5. Reproducibility challenge: Relies on the stability of airflow dispersion; fluctuations in parameters (pressure, humidity) can easily lead to variations in results. 6. High maintenance costs: The particle size analyzer is placed in a glove box, which is difficult to clean after the test. In addition, it is equipped with a precision airflow control system, resulting in high maintenance costs.

[0005] Traditional wet methods often use water or ethanol as the dispersion medium, but solid electrolytes readily react with water or ethanol. Currently, particle size distribution testing of special materials in the industry also uses other organic reagents as dispersion media. However, single-component dispersion systems are prone to sample aggregation or sedimentation, and most organic reagents are toxic. For example, CN202410228055.1 mentions the use of one or more low-polarity solvents, such as n-heptane, n-hexane, cyclohexane, toluene, xylene, and anisole. These reagents have varying degrees of toxicity, chronic neurotoxicity, carcinogenicity, volatility, and flammability, which may endanger the health of laboratory personnel, pose safety risks, and are environmentally unfriendly; therefore, this method is not suitable for widespread application. Thus, to meet the needs of batch testing and the principle of environmental friendliness, if wet methods are used to analyze such samples, it is necessary to develop novel dispersion systems that combine safety, environmental friendliness, and compatibility.

[0006] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this application is to provide a method for testing the particle size distribution of inorganic solid electrolytes, which aims to solve the problem that sample agglomeration or sedimentation is easy to occur in the existing laser diffraction wet analysis of inorganic solid electrolytes.

[0008] The technical solution of this application is as follows: A method for testing the particle size distribution of an inorganic solid electrolyte, comprising the following steps: Span80 is mixed with light paraffin oil to prepare a light paraffin oil solution; wherein the volume concentration of Span80 in the light paraffin oil solution is 0.1-10%; The inorganic solid electrolyte was mixed with the light paraffin oil solution to obtain a sample suspension; The particle size of the sample suspension was determined by laser diffraction.

[0009] In this application, by selecting a non-toxic and stable dispersion medium, optimizing the dispersant formulation, and choosing suitable dispersion conditions, an inorganic solid electrolyte suspension that is uniformly dispersed, free from sedimentation and agglomeration can be prepared.

[0010] The particle size distribution test method for the inorganic solid electrolyte, wherein when the inorganic solid electrolyte is an oxide electrolyte or a halide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is 10%; When the inorganic solid electrolyte is a sulfide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is 2%.

[0011] The method for testing the particle size distribution of the inorganic solid electrolyte, wherein 0.05-0.2g of the inorganic solid electrolyte is mixed with 50mL of the light paraffin oil solution.

[0012] In the embodiments of this application, the concentration of Span80 needs to be increased to obtain a stable and well-dispersed suspension when measuring oxide electrolytes or halide electrolytes; a concentration of 2% is required to obtain a stable and well-dispersed suspension when measuring sulfide electrolytes.

[0013] The particle size distribution testing method for the inorganic solid electrolyte, wherein the process of mixing the inorganic solid electrolyte with the light paraffin oil solution specifically includes the following steps: Under stirring conditions, the inorganic solid electrolyte is added to the light paraffin oil solution in portions, and stirring is continued for more than 5 minutes after the addition is completed to obtain a mixture. The mixture is then subjected to ultrasonic dispersion.

[0014] The particle size distribution test method for the inorganic solid electrolyte, wherein the stirring speed is 1000-1500 rpm; The ultrasonic dispersion process involves ultrasonic treatment at 200-800W for 5-30 minutes.

[0015] The method for testing the particle size distribution of the inorganic solid electrolyte, wherein when the particle size of the inorganic solid electrolyte is in the nanometer range, the ultrasonic dispersion process is ultrasonication at 300-800W for 10-30 minutes. When the particle size of the inorganic solid electrolyte is in the micrometer range, the ultrasonic dispersion process is ultrasonication at 200W-300W for 5-15 minutes.

[0016] The particle size distribution test method for the inorganic solid electrolyte, wherein the process of adding the inorganic solid electrolyte to the light paraffin oil solution in portions is carried out in a glove box under an inert atmosphere.

[0017] The method for testing the particle size distribution of the inorganic solid electrolyte, wherein the mixture is sealed in a sealed container before undergoing the ultrasonic dispersion treatment.

[0018] The method for testing the particle size distribution of inorganic solid electrolytes, wherein the process of testing the particle size of the sample suspension by laser diffraction includes the following steps: Input the refractive index and absorptivity of the inorganic solid electrolyte, as well as the refractive index of the light paraffin oil, into the laser particle size analyzer; The light paraffin oil solution was injected into the laser particle size analyzer, the circulation and stirring functions were turned on, and after the air was removed, a blank background scan was performed. Set the circulation speed to 3-5 L / min, add the sample suspension dropwise into the sample loading tank, observe the transmittance column, and adjust the sample concentration until the transmittance of the light source falls between 80% and 90%. After the sample concentration has stabilized for 5-10 seconds, the measurement should be performed.

[0019] The method for testing the particle size distribution of the inorganic solid electrolyte, wherein when the particle size of the inorganic solid electrolyte is below 100 nm, a light source with a wavelength of 405 nm is used for measurement; When the particle size of the inorganic solid electrolyte is above 100 nm, a light source with a wavelength of 650 nm is used for measurement.

[0020] Beneficial effects: The particle size distribution test method of inorganic solid electrolytes in this application can prepare a uniformly dispersed inorganic solid electrolyte suspension without sedimentation and agglomeration by selecting a non-toxic and stable dispersion medium, optimizing the dispersant formulation, and choosing suitable dispersion conditions, thereby obtaining ideal test results. Attached Figure Description

[0021] Figure 1 This is a wet particle size distribution diagram of the halide solid electrolyte in Example 1 of this application.

[0022] Figure 2 This is a scanning electron microscope image of the halide solid electrolyte in Example 1 of this application.

[0023] Figure 3 This is a wet particle size distribution diagram of the oxide solid electrolyte in Example 2 of this application.

[0024] Figure 4 This is a scanning electron microscope image of the oxide solid electrolyte in Example 2 of this application.

[0025] Figure 5 This is a wet particle size distribution diagram of the sulfide solid electrolyte in Example 3 of this application.

[0026] Figure 6 This is a scanning electron microscope image of the sulfide solid electrolyte in Example 3 of this application.

[0027] Figure 7 This is a wet particle size distribution diagram of sulfide solid electrolytes for four different testing methods in Example 3 and Comparative Examples 1-3 of this application. Detailed Implementation

[0028] This application provides a method for testing the particle size distribution of inorganic solid electrolytes. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following provides a more detailed description. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0029] This application provides a method for testing the particle size distribution of inorganic solid electrolytes, wherein the inorganic solid electrolytes refer to oxide electrolytes, sulfide electrolytes, and halide electrolytes. In this application, by selecting a non-toxic and stable dispersion medium, optimizing the dispersant formulation, and choosing suitable dispersion conditions, a uniformly dispersed inorganic solid electrolyte suspension without sedimentation or agglomeration can be prepared.

[0030] Specifically, the particle size distribution testing method for inorganic solid electrolytes in this application includes the following steps: (1) Prepare the dispersion medium solution.

[0031] In this application, light paraffin oil is used as the dispersion medium and Span80 is used as the dispersant. Specifically, the process of preparing the dispersion medium solution includes the following: Span80 was mixed with light paraffin oil to prepare a light paraffin oil solution containing Span80. The volume concentration of Span80 in the light paraffin oil solution was 0.1-10%. Since there are many types of solid electrolytes, the dispersing effect of Span80 varies from sample to sample; therefore, the range here is 0.1-10%. When applying it to tests, it is necessary to adjust the concentration appropriately according to the actual situation of the sample and with reference to the industrial production dosage. To obtain a stable and well-dispersed suspension, the concentration of Span80 should be minimized to avoid introducing impurities due to impurities in the Span80 reagent.

[0032] When the inorganic solid electrolyte is an oxide electrolyte or a halide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is preferably 10%. In the embodiments of this application, the concentration of Span80 needs to be increased to obtain a stable and well-dispersed suspension when using either oxide or halide electrolytes. Oxide electrolytes or halide electrolytes generally have trace amounts of hydroxyl groups or adsorbed water on their surfaces, exhibiting weak hydrophilicity. Light liquid paraffin (contact angle > 90°) cannot effectively wet the particle surface, easily inducing aggregation. Span80, with an HLB value of ≈ 4.3, contains both hydrophilic and hydrophobic groups, simultaneously satisfying the weak hydrophilicity of the sample particles and the hydrophobicity of the liquid paraffin. Therefore, appropriately increasing the proportion of Span80 is beneficial for improving dispersion stability.

[0033] When the inorganic solid electrolyte is a sulfide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is preferably 2%. In the embodiments of this application, a 2% concentration of the sulfide electrolyte is required in actual testing to obtain a stable and well-dispersed suspension.

[0034] Light paraffin oils are chemically inert and have low volatility, making them less likely to cause reactions or dissolution of solid electrolytes. While they may produce seemingly reasonable results when used alone, slight agglomeration may occur. This is because many inorganic solid electrolytes have high surface polarity and poor compatibility with hydrophobic paraffin oils, leading to easy agglomeration. Currently, commonly used dispersants in wet assays include sodium hexametaphosphate, polyvinyl alcohol, sodium polyacrylate, and sodium dodecylbenzene sulfonate. Span 80, however, is classified as "low toxicity" or "practically non-toxic," making it a human health-friendly reagent. It is frequently used as an emulsifier in the food, cosmetics / personal care, and pharmaceutical industries, and is used sporadically as an emulsifier or lubricant in industrial applications, rarely used in analytical testing. Span 80 is a low HLB value oil-soluble surfactant that excels at forming and stabilizing water-in-oil emulsions. It effectively reduces the solid / oil interfacial tension between inorganic solid electrolyte particles and light paraffin oil, significantly improving wettability, helping particles to be wetted by oil, reducing the formation of large agglomerates, and forming stable water-in-oil emulsions. Meanwhile, the refractive index of light paraffin oil is close to that of most inorganic solid electrolytes, which can reduce light scattering errors. Furthermore, Span 80 is relatively inexpensive. Therefore, in general, the advantages of combining light paraffin oil and Span 80 are that it improves the wettability between inorganic solid electrolyte particles and light paraffin oil, and it is also low-cost, has good optical compatibility, is safe to operate, and is harmless to the human body.

[0035] Meanwhile, this application also compared and verified the test method using n-heptane as the dispersion medium, and found that it did not achieve the optimal dispersion effect for the sample. The test results showed that the sample particle agglomeration phenomenon still existed. In addition, n-heptane has low toxicity, but it also poses safety risks and is environmentally unfriendly.

[0036] (2) Mix the inorganic solid electrolyte with the dispersion medium solution to obtain the sample suspension.

[0037] In this step, 50 mL of dispersion medium solution can be added for every 0.05-0.2 g of inorganic solid electrolyte. The lower the concentration of the sample suspension, the easier it is to achieve the desired dispersion effect in subsequent processing. However, below this ratio, there is a risk that the concentration of the sample suspension may be too low to meet the requirement of "light transmittance falling between 80% and 90%". The process of mixing the inorganic solid electrolyte with the dispersion medium solution specifically includes the following steps: Under stirring conditions, the inorganic solid electrolyte is slowly and gradually added to the dispersion medium solution in small portions. After the addition is complete, stirring is continued for more than 5 minutes to obtain a mixed solution. The mixture is then subjected to ultrasonic dispersion.

[0038] Specifically, after adding the inorganic solid electrolyte to the dispersion medium solution, it is stirred using a magnetic stirrer. Generally, stirring for 5 minutes yields a homogeneous mixture. The stirring time can be appropriately extended, but this will lead to lower testing efficiency; therefore, a stirring time of 5 minutes is preferred. The stirring speed of a typical magnetic stirrer is set within the range of 0-1500 rpm. To improve testing efficiency, the stirring speed can be set to the maximum, therefore, a stirring speed of 1000-1500 rpm is acceptable.

[0039] Specifically, the ultrasonic dispersion process involves sonication at 200-800W for 5-30 minutes. Solid-state electrolyte technology is progressing from micrometer-scale to nanometer-scale; therefore, the ultrasonic dispersion parameters differ for inorganic solid-state electrolytes of different particle sizes. For nanometer-scale inorganic solid-state electrolytes, longer ultrasonic time and increased ultrasonic power are required to prevent agglomeration. For micrometer-scale inorganic solid-state electrolytes, stable suspensions can be obtained at relatively low ultrasonic intensity and time; increasing ultrasonic time and intensity may actually increase the risk of sample fragmentation and decomposition.

[0040] When the particle size of the inorganic solid electrolyte is in the nanometer range, the ultrasonic dispersion process is preferably performed at 300-800W for 10-30 minutes. The optimal value should be selected based on the actual sample condition, and the test results can be verified using scanning electron microscopy (SEM). If the test results are smaller than those obtained using SEM, the ultrasonic power should be reduced or the ultrasonic time shortened.

[0041] When the particle size of the inorganic solid electrolyte is in the micrometer range, the ultrasonic dispersion process is preferably performed at 200W-300W for 5-15 minutes. The optimal value should be selected based on the actual sample condition, and the test results can be verified using scanning electron microscopy (SEM). If the test results are smaller than those obtained using SEM, the ultrasonic power should be reduced to 200W, or the ultrasonic time shortened.

[0042] Furthermore, to ensure that the sample does not react with air, the inorganic solid electrolyte is slowly and gradually added to the dispersion medium solution in small portions within an inert atmosphere glove box; the mixture is then sealed in a sealed container and subjected to ultrasonic dispersion. Any gas (argon) that may be introduced into the glove box during stirring is removed during subsequent ultrasonic dispersion.

[0043] (3) The particle size of the sample suspension was tested by laser diffraction.

[0044] Specifically, the process of particle size determination of a sample suspension using laser diffraction includes the following steps: Using the Mie scattering theory model, the refractive index and absorptivity of the inorganic solid electrolyte, as well as the refractive index of light paraffin oil, were input into the laser particle size analyzer. Inject the dispersion medium solution into the laser particle size analyzer, turn on the circulation and stirring functions, remove air, and then perform a blank background scan. Set the circulation rate to 3-5 L / min, add the sample suspension dropwise into the sample loading tank, observe the transmittance column, and adjust the sample concentration until the transmittance of the light source falls between 80% and 90%. After the sample concentration stabilizes for 5-10 seconds, measurements are taken. In this step, the refractive index of light paraffin oil is 1.480. The refractive index and absorbance of the inorganic solid electrolyte can be obtained by consulting relevant literature.

[0045] Regarding the light source, inorganic solid electrolytes with a particle size of less than 100 nm are preferably measured using a light source with a wavelength of 405 nm, while inorganic solid electrolytes with a particle size of more than 100 nm are preferably measured using a light source with a wavelength of 650 nm.

[0046] In this step, the circulation rate is set to 3-5 L / min. If it is too high, air bubbles will be introduced; if it is too low, insufficient circulation will result in unstable test results.

[0047] The particle size distribution testing method for inorganic solid electrolytes in this application has the following advantages: 1. Obtaining ideal test results: When using the method of this application to test the particle size of inorganic solid electrolytes, the sample does not react with air, has good dispersibility, and the precision and accuracy of the test results are quite ideal; 2. Save on equipment configuration costs: The laser particle size analyzer uses an organic solvent wet process system, eliminating the need for an additional glove box adapted to the particle size analyzer; 3. Improved ease of operation: The laser particle size analyzer can be placed in a conventional experimental environment, making experimental operation and maintenance more convenient than when placed in a glove box; 4. Ensuring test safety: The dispersion medium used in the wet test is liquid light paraffin, which has excellent chemical stability, hydrophobicity, non-toxicity, and non-corrosiveness, and is relatively friendly to the human body and equipment; Span80 is used as a dispersant, which has a high safety profile; the method of this application effectively isolates the sample from air, and the sample will not react to generate toxic gases. 5. Good sample dispersibility: The sample treated by the method of this application can effectively reduce agglomeration and exhibit good sample dispersibility, thereby obtaining an inorganic solid electrolyte suspension that is uniformly dispersed, without sedimentation and agglomeration. 6. Reduced sample consumption: Wet testing can achieve measurement by diluting a small amount of sample, which requires relatively less sample than dry testing. 7. Ensure data repeatability: Dry testing relies on the stability of airflow dispersion, and fluctuations in parameters (pressure, humidity) can easily lead to variations in results, while the dispersion conditions of wet testing are easier to standardize and have better reproducibility. 8. Relatively low maintenance costs: The wet testing system is easy to clean, and the instrument does not need to be placed in the glove box, which greatly saves maintenance costs.

[0048] The present application will be further described below through specific embodiments.

[0049] Example 1: Halide Solid Electrolyte

[0050] Specific implementation steps: 1. Using light paraffin oil as the dispersion medium, take 5 mL of Span80 (CAS No.: 1338-43-8) and dilute to 50 mL with light paraffin oil (density 0.83-0.86 g / mL, purchased from Maclean) as the solvent to prepare a light paraffin oil solution containing 10% Span80.

[0051] 2. In an inert atmosphere glove box, measure 50 mL of the above light paraffin oil solution into a sealed container, place a stir bar inside, and stir on a stirrer at a speed of 1500 rpm. While stirring, slowly and gradually add approximately 0.1 g of halide solid electrolyte LIC powder, and continue stirring for 5 min. Cover the sealed container, remove it from the glove box, and place it in an ultrasonic cleaner. Sonicate at 800 W for 30 min to prepare the sample suspension to be tested, and use it for measurement immediately.

[0052] 3. Measurement parameter settings: ① Using the Mie scattering theory model, input the refractive index and absorptivity of the scattering particles and the refractive index of the dispersion medium: the refractive index of light paraffin oil is 1.480, the refractive index of halide solid electrolyte LIC powder is 1.6, and the absorptivity is 0.1. ② Circulation speed: 4L / min; ③ A 650nm light source is used for measurement.

[0053] 4. Measurement: ① Inject light paraffin oil solution, turn on the circulation and stirring functions of the equipment, and use the equipment function to remove air before performing a blank background scan; ② Use a dropper to take an appropriate amount of sample suspension and drop it into the sample loading tank, observe the transmittance column, slowly add the sample, and adjust the sample concentration until the light source transmittance falls between 80% and 90%; ④ Measure after the sample concentration has stabilized for 5 seconds.

[0054] The above steps were performed three times consecutively, and the results were compared with those from dry method testing and scanning electron microscopy testing. The results are shown in Table 1 and... Figure 1-2 As shown.

[0055] The dry method involves testing at a dew point of -50°C in a drying room. Before testing, the sample is lightly ground or sieved. Instrument settings include a dispersion pressure of 1.0 bar and a medium-low injection speed. The Mie scattering theory model is used, with the halide solid electrolyte LIC powder having a refractive index of 1.6 and an absorbance of 0.1. Nitrogen gas is used as the dispersion medium.

[0056] Table 1

[0057] From Table 1 and Figure 1-2 It can be seen that the test results of this embodiment are consistent with those of other methods. The sample suspension showed no aggregation or sedimentation, and the particle size distribution results were ideal.

[0058] Example 2: Oxide Solid Electrolyte

[0059] Specific implementation steps: 1. Using light paraffin oil as the dispersion medium, take 5 mL of Span80 (CAS No.: 1338-43-8) and dilute to 50 mL with light paraffin oil (density 0.83-0.86 g / mL, purchased from Maclean) as the solvent to prepare a light paraffin oil solution containing 10% Span80.

[0060] 2. In an inert atmosphere glove box, measure 50 mL of the above light paraffin oil solution into a sealed container, place a stir bar inside, and stir on a stirrer at 1500 rpm. While stirring, slowly and gradually add approximately 0.1 g of the oxide solid electrolyte LATP powder, and continue stirring for 5 min. Cover the sealed container, remove it from the glove box, and place it in an ultrasonic cleaner. Sonicate at 800 W for 30 min to prepare the sample suspension to be tested, and use it for measurement immediately.

[0061] 3. Measurement parameter settings: ① Using the Mie scattering theory model, input the refractive index and absorptivity of the scattering particles and the refractive index of the dispersion medium: light paraffin oil has a refractive index of 1.480, and the oxide solid electrolyte LATP powder has a refractive index of 1.8 and an absorptivity of 0.1. ② Circulation rate: 4L / min; ③ A 650nm light source is used for measurement.

[0062] 4. Measurement: ① Inject light paraffin oil solution, turn on the circulation and stirring functions of the equipment, and use the equipment function to remove air before performing a blank background scan; ② Use a dropper to take an appropriate amount of sample suspension and drop it into the sample loading tank, observe the transmittance column, slowly add the sample, and adjust the sample concentration until the light source transmittance falls between 80% and 90%; ④ Measure after the sample concentration has stabilized for 5 seconds.

[0063] The above steps were performed three times consecutively, and the results were compared with those obtained using scanning electron microscopy. The results are shown in Table 2. Figure 3-4 As shown.

[0064] Table 2

[0065] From Table 2 and Figure 3-4 It can be seen that the test results of this embodiment are consistent with the scanning electron microscope test results. The sample suspension showed no aggregation or sedimentation, and the particle size distribution results were ideal.

[0066] Example 3: Sulfide Solid Electrolyte

[0067] Specific implementation steps: 1. Using light paraffin oil as the dispersion medium, take 1 mL of Span80 (CAS No.: 1338-43-8) and dilute to 50 mL with light paraffin oil (density 0.83-0.86 g / mL, purchased from Maclean) as the solvent to prepare a light paraffin oil solution containing 2% Span80.

[0068] 2. In an inert atmosphere glove box, measure 50 mL of the above light paraffin oil solution into a sealed container, place a stir bar inside, and stir on a stirrer at a speed of 1000 rpm. While stirring, slowly add approximately 0.1 g of sulfide solid electrolyte LPSC powder in small portions, and continue stirring for 5 min. Cover the sealed container, remove it from the glove box, and place it in an ultrasonic cleaner. Sonicate at 300 W for 10 min to prepare the sample suspension to be tested and measure it quickly.

[0069] 3. Measurement parameter settings: ① Using the Mie scattering theory model, input the refractive index and absorptivity of the scattering particles and the refractive index of the dispersion medium: light paraffin oil has a refractive index of 1.480, sulfide solid electrolyte LPSC powder has a refractive index of 1.8 and an absorptivity of 0.1. ② Circulation speed: 5L / min; ③ A 650nm light source is used for measurement.

[0070] 4. Measurement: ① Inject light paraffin oil solution, turn on the circulation and stirring functions of the equipment, and use the equipment function to remove air before performing a blank background scan; ② Use a dropper to take an appropriate amount of the dispersed solid electrolyte suspension and drop it into the sample loading tank, observe the transmittance column, and adjust the sample concentration until the light source transmittance falls between 80% and 90%; ④ Measure after the sample has stabilized for 5 seconds.

[0071] The above steps were performed three times consecutively, and the results were compared with those obtained using scanning electron microscopy. The results are shown in Table 3. Figure 5-6 As shown.

[0072] Table 3

[0073] From Table 3 and Figure 5-6 It can be seen that the test results of this embodiment are consistent with the scanning electron microscope test results. The sample suspension showed no aggregation or sedimentation, and the particle size distribution results were ideal.

[0074] Comparative Example: Comparison of Dispersion Media for Sulfide Solid Electrolytes Comparative Example 1: Using n-heptane as the dispersion medium, without adding a dispersant. 2.5 mg of a sulfide solid electrolyte sample was placed in a 20 mL sample bottle, 15 mL of n-heptane was added, and the mixture was shaken well. The sample was then ultrasonically dispersed for 2 min at a frequency of 40 kHz. Except for the refractive index of n-heptane (1.388), all other measurement parameters were the same as in Example 3. After injecting the n-heptane dispersion medium into a laser particle size analyzer, a blank was scanned. The sample was slowly added dropwise until the transmittance of the light source reached between 87% and 93%, and the measurement was performed after stabilizing for 5 seconds.

[0075] Comparative Example 2: Using n-heptane as the dispersion medium and adding soybean lecithin as the dispersant. 2.5 mg of the sulfide solid electrolyte sample was placed in a 20 mL sample bottle, 15 mL of n-heptane and 0.5 mL of soybean lecithin were added, and the mixture was shaken well. The mixture was then ultrasonically dispersed for 2 min at a frequency of 40 kHz. Except for the refractive index of n-heptane (1.388), all other measurement parameters were the same as in Example 3. After injecting the n-heptane dispersion medium into a laser particle size analyzer, a blank was scanned. The sample was slowly added dropwise until the transmittance of the light source reached between 87% and 93%, and the measurement was performed after stabilizing for 5 seconds.

[0076] Comparative Example 3: Sulfide solid electrolyte LPSC powder was used as the test object, light paraffin oil was used as the dispersion medium, and 2% soybean lecithin was added as the dispersant. The remaining operation steps were the same as in Example 3.

[0077] The results are shown in Table 4 and Figure 7 As shown, compared with Example 3, Comparative Example 1 and Comparative Example 2 show a rightward shift in the distribution curve, an increase in the mode particle size, and D. 50,3 The peak frequency increased, while the peak broadening and peak height reduction were significant. This broadening and reduction in peak height may be due to improper sample pretreatment conditions, leading to increased aggregation and decreased dispersion stability. Compared to Comparative Example 1, Comparative Example 2 showed a decrease in D. 50,3 The sample is closer to Example 3, possibly due to the addition of a surfactant, which slows down particle aggregation. Meanwhile, the dispersion medium used in Example 3 is non-toxic and non-corrosive, making it more human- and environmentally friendly and suitable for widespread use. Comparative Example 3 shows a bimodal distribution, indicating significant particle aggregation and suggesting that the combination of light liquid paraffin and soybean lecithin has poor anti-aggregation ability.

[0078] Table 4

[0079] The test method using n-heptane as a dispersion medium was verified through the above Example 3 and comparative examples. It was found that the optimal dispersion effect of the sample was not achieved, and the test results showed that the particle agglomeration phenomenon of the sample still existed.

[0080] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.

Claims

1. A method for testing the particle size distribution of inorganic solid electrolytes, characterized in that, Includes the following steps: Span80 is mixed with light paraffin oil to prepare a light paraffin oil solution; wherein the volume concentration of Span80 in the light paraffin oil solution is 0.1-10%; The inorganic solid electrolyte was mixed with the light paraffin oil solution to obtain a sample suspension; The particle size of the sample suspension was determined by laser diffraction.

2. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 1, characterized in that, When the inorganic solid electrolyte is an oxide electrolyte or a halide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is 10%; When the inorganic solid electrolyte is a sulfide electrolyte, the volume concentration of Span80 in the light paraffin oil solution is 2%.

3. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 1, characterized in that, Each 0.05-0.2g of the inorganic solid electrolyte is mixed with 50mL of the light paraffin oil solution.

4. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 1, characterized in that, The process of mixing the inorganic solid electrolyte with the light paraffin oil solution specifically includes the following steps: Under stirring conditions, the inorganic solid electrolyte is added to the light paraffin oil solution in portions, and stirring is continued for more than 5 minutes after the addition is completed to obtain a mixture. The mixture is then subjected to ultrasonic dispersion.

5. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 4, characterized in that, The stirring speed is 1000-1500 rpm; The ultrasonic dispersion process involves ultrasonic treatment at 200-800W for 5-30 minutes.

6. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 5, characterized in that, When the particle size of the inorganic solid electrolyte is in the nanometer range, the ultrasonic dispersion process is ultrasonication at 300-800W for 10-30 minutes. When the particle size of the inorganic solid electrolyte is in the micrometer range, the ultrasonic dispersion process is ultrasonication at 200W-300W for 5-15 minutes.

7. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 4, characterized in that, The process of adding the inorganic solid electrolyte to the light paraffin oil solution in portions is carried out in a glove box under an inert atmosphere.

8. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 4, characterized in that, The mixture is sealed in a sealed container before undergoing the ultrasonic dispersion treatment.

9. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 1, characterized in that, The process of measuring the particle size of the sample suspension using laser diffraction includes the following steps: Input the refractive index and absorptivity of the inorganic solid electrolyte, as well as the refractive index of the light paraffin oil, into the laser particle size analyzer; The light paraffin oil solution was injected into the laser particle size analyzer, the circulation and stirring functions were turned on, and after the air was removed, a blank background scan was performed. Set the circulation speed to 3-5 L / min, add the sample suspension dropwise into the sample loading tank, observe the transmittance column, and adjust the sample concentration until the transmittance of the light source falls between 80% and 90%. After the sample concentration has stabilized for 5-10 seconds, the measurement should be performed.

10. The method for testing the particle size distribution of inorganic solid electrolytes according to claim 9, characterized in that, When the particle size of the inorganic solid electrolyte is below 100 nm, a light source with a wavelength of 405 nm is used for measurement; When the particle size of the inorganic solid electrolyte is above 100 nm, a light source with a wavelength of 650 nm is used for measurement.

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