Method and device for detecting silicon content in silicon-based electrode material

Abstract

The invention relates to a method and a device for detecting the content of silicon in a silicon-based electrode material. The method for detecting the silicon content in the silicon-based electrode material comprises the following steps: mixing a to-be-detected silicon-based electrode material with alkali liquor, and carrying out first reaction to obtain first slurry; performing first solid-liquid separation treatment on the first slurry to obtain a first solid material and first filtrate; mixing the first solid material with an aqua regia solution, and carrying out a second reaction to obtain a second slurry; performing second solid-liquid separation treatment on the second slurry to obtain a second solid material and a second filtrate; respectively detecting the silicon content in the first filtrate and the second filtrate, and calculating the silicon content in the silicon-based electrode material according to the silicon content in the first filtrate and the silicon content in the second filtrate. The method for detecting the silicon content in the silicon-based electrode material is simple in operation steps, has a good extraction effect on silicon in the silicon-based electrode material, and can improve the detection accuracy of the silicon content in the silicon-based electrode material.

Description

Technical Field

[0001] The present application relates to the field of chemical analysis technology, and in particular to a method and device for detecting silicon content in a silicon-based electrode material. Background Art

[0002] Silicon-based electrode materials have high theoretical specific capacity and have broad application prospects in the fields of lithium-ion batteries. The silicon content in silicon-based electrode materials has a great influence on the performance and stability of the battery.

[0003] In the traditional detection method of silicon content in silicon-based electrode materials, it is difficult to take into account both good silicon extraction effect and simple operation steps. Summary of the invention

[0004] Based on this, it is necessary to provide a method and device for detecting the silicon content in a silicon-based electrode material. The method for detecting the silicon content in a silicon-based electrode material of the present application has simple operation steps and can also have a good extraction effect on the silicon in the silicon-based electrode material, thereby improving the detection accuracy of the silicon content in the silicon-based electrode material.

[0005] In a first aspect, the present application provides a method for detecting silicon content in a silicon-based electrode material, comprising the following steps:

[0006] Mixing the silicon-based electrode material to be tested with an alkaline solution, and performing a first reaction to obtain a first slurry;

[0007] Performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate;

[0008] The first solid material and the aqueous regia solution are mixed and subjected to a second reaction to obtain a second slurry;

[0009] performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate;

[0010] The silicon contents in the first filtrate and the second filtrate are detected respectively, and the silicon content in the silicon-based electrode material is calculated according to the silicon content in the first filtrate and the silicon content in the second filtrate.

[0011] In some embodiments, the solute of the alkali solution includes at least one of sodium hydroxide and potassium hydroxide.

[0012] In some embodiments, the mass concentration of the solute in the alkali solution is 5% to 20%.

[0013] In some of the embodiments, the mass ratio of the silicon-based electrode material to be tested to the solute in the alkaline solution is 1:(8-12).

[0014] In some embodiments, the temperature of the first reaction is 115°C to 125°C.

[0015] In some embodiments, the first reaction time is 160 min to 200 min.

[0016] In some embodiments, the volume ratio of aqua regia and deionized water in the aqua regia solution is (3-7):5.

[0017] In some embodiments, the volume ratio of the mass of the silicon-based electrode material to be tested to the aqua regia solution is 1 g:8 mL to 1 g:12 mL.

[0018] In some embodiments, the temperature of the second reaction is 115°C to 125°C.

[0019] In some embodiments, the second reaction time is 25 min to 35 min.

[0020] In some embodiments, after performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate, the following steps are further included:

[0021] The first solid material is washed with deionized water to obtain a first washing liquid, and the first washing liquid and the first filtrate are mixed.

[0022] In some embodiments, after performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate, the following steps are also included:

[0023] The second solid material is washed with deionized water to obtain a second washing liquid, and the second washing liquid and the second filtrate are mixed.

[0024] In some embodiments, detecting the silicon content in the first filtrate and the second filtrate respectively comprises the following steps:

[0025] The silicon concentrations in the first filtrate and the second filtrate are respectively detected by inductively coupled plasma mass spectrometry.

[0026] In some embodiments, detecting the silicon concentration in the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry comprises the following steps:

[0027] Prepare silicon standard solutions of different concentrations;

[0028] The silicon concentration in each silicon standard solution is measured by inductively coupled plasma mass spectrometry to obtain a response value-concentration curve;

[0029] Testing the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry to obtain a first response value of the first filtrate and a second response value of the second filtrate;

[0030] The first response value, the second response value and the response value-concentration curve are compared respectively to obtain the silicon concentration in the first filtrate and the second filtrate.

[0031] In some embodiments, the silicon-based electrode material includes at least one of lithium orthosilicate and a composite material thereof.

[0032] In a second aspect, the present application provides a device for detecting silicon content in a silicon-based electrode material, comprising: a first reaction device, a first solid-liquid separation device, a second reaction device, a second solid-liquid separation device and a detection device; wherein,

[0033] The first reaction device is used to mix the silicon-based electrode material to be tested with an alkaline solution, and obtain a first slurry through a first reaction;

[0034] The first solid-liquid separation device is used to perform a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate;

[0035] The second reaction device is used to mix the first solid material and the aqueous regia solution, and obtain a second slurry through a second reaction;

[0036] The second solid-liquid separation device is used to perform a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate;

[0037] The detection device is used to detect the silicon content in the first filtrate and the second filtrate respectively, and calculate the silicon content in the silicon-based electrode material according to the silicon content in the first filtrate and the silicon content in the second filtrate.

[0038] In the above-mentioned method for detecting the silicon content in the silicon-based electrode material, an alkali solution and the silicon-based electrode material to be tested are first reacted to obtain a first filtrate, i.e., an alkali-soluble silicon liquid, and then an aqua regia solution and the first solid material after the first reaction are reacted to obtain a second filtrate, i.e., an acid-soluble silicon liquid. The above-mentioned method can achieve a high extraction rate for silicon in the silicon-based electrode material. Then, the silicon content in the first filtrate and the second filtrate is detected respectively, and the silicon content in the silicon-based electrode material can be calculated by the silicon content in the first filtrate and the silicon content in the second filtrate. The method for detecting the silicon content in the silicon-based electrode material of the present application has simple operating steps, and can also have a good extraction effect on the silicon in the silicon-based electrode material, and can improve the detection accuracy of the silicon content in the silicon-based electrode material. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] An embodiment of the present application provides a method for detecting silicon content in a silicon-based electrode material, comprising the following steps:

[0044] Mixing the silicon-based electrode material to be tested with an alkaline solution, and performing a first reaction to obtain a first slurry;

[0045] Performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate;

[0046] The first solid material and the aqueous regia solution are mixed and subjected to a second reaction to obtain a second slurry;

[0047] Performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate;

[0048] The silicon contents in the first filtrate and the second filtrate are detected respectively, and the silicon content in the silicon-based electrode material is calculated according to the silicon content in the first filtrate and the silicon content in the second filtrate.

[0049] In the above-mentioned method for detecting the silicon content in the silicon-based electrode material, an alkali solution and the silicon-based electrode material to be tested are first reacted for a first time, and a first filtrate, i.e., an alkali-soluble silicon liquid, is obtained, and then an aqueous regia solution and the first solid material after the first reaction are reacted for a second time, and a second filtrate, i.e., an acid-soluble silicon liquid, is obtained. The above-mentioned method can achieve a high extraction rate of silicon in the silicon-based electrode material. Then, the silicon content in the first filtrate and the second filtrate is detected respectively, and the silicon content in the silicon-based electrode material can be calculated by the silicon content in the first filtrate and the silicon content in the second filtrate. It can be understood that the extraction rate of silicon in the silicon-based electrode material in the detection method of the silicon content in the silicon-based electrode material of the present application is high, so the silicon content in the silicon-based electrode material can be directly calculated by adding the silicon content in the first filtrate and the silicon content in the second filtrate. The detection method of the silicon content in the silicon-based electrode material of the present application has simple operation steps, and can also have a good extraction effect on the silicon in the silicon-based electrode material, and can improve the detection accuracy of the silicon content in the silicon-based electrode material.

[0050] Furthermore, the method for detecting silicon content in silicon-based electrode materials of the present application also has the following advantages:

[0051] 1. Simplified chemical reagents and steps for sample pretreatment. The pretreatment reagents required for this application are few and relatively conventional, only alkali solution and aqua regia solution. Compared with the existing sample treatment methods, there is no need to use chemical reagents such as ammonium nitrate, potassium pyrosulfate, hydrofluoric acid, lithium borate, etc., and there is no need for complex pretreatment steps such as high-temperature melting, thermal swelling transfer, high-temperature volatilization of hydrofluoric acid, and repeated drying to constant weight, which reduces the test time cost and improves work efficiency.

[0052] 2. Reduced equipment costs for pre-treatment and testing. The pre-treatment equipment in this application only needs to use an ordinary electric heating plate, without the need for a high-temperature furnace and a platinum crucible; the testing equipment only needs ICP-OES and conventional liquid standards, without the need to purchase specific solid standards and XRF equipment, and the operating cost of the ICP-OES equipment is low.

[0053] 3. High accuracy and stability of test data. The detection method of the present application is applicable to lithium silicate composite materials doped with metals of different concentrations for batteries, has a wide range of applications, high accuracy of test data, and good test repeatability.

[0054] In some of the embodiments, the mass concentration of the solute in the alkali solution is 5% to 20%.

[0055] Within the above range of mass concentration of the solute in the alkali solution, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the mass concentration of the solute in the alkali solution is 5%, 8%, 10%, 12%, 15%, 18% or 20%, or the mass concentration of the solute in the alkali solution can also be within the range between any two of the above concentrations.

[0056] In some of the embodiments, the mass ratio of the silicon-based electrode material to be tested and the solute in the alkaline solution is 1:(8~12).

[0057] Within the range of the mass ratio of the silicon-based electrode material to be tested and the solute in the alkali solution, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the mass ratio of the silicon-based electrode material to be tested and the solute in the alkali solution is 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5 or 1:12, or the mass ratio of the silicon-based electrode material to be tested and the solute in the alkali solution can also be within the range between any two of the above mass ratios.

[0058] In some embodiments, the temperature of the first reaction is 115°C to 125°C.

[0059] In the temperature range of the first reaction, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the temperature of the first reaction is 115°C, 116°C, 117°C, 118°C, 119°C, 120°C, 121°C, 122°C, 123°C, 124°C or 125°C, or the temperature of the first reaction can also be within the range between any two of the above temperatures.

[0060] In some embodiments, the first reaction time is 160 min to 200 min.

[0061] Within the time range of the first reaction, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the time of the first reaction is 160 min, 165 min, 170 min, 175 min, 180 min, 185 min, 190 min, 195 min or 200 min, or the time of the first reaction can also be within the range between any two of the above times.

[0062] In some embodiments, the volume ratio of aqua regia and deionized water in the aqua regia solution is (3-7):5.

[0063] It is understood that the aqua regia solution refers to a mixture of aqua regia and deionized water. Aqua regia is a mixture of concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1. Optionally, the volume ratio of aqua regia and deionized water in the aqua regia solution is 3:5, 4:5, 5:5, 6:5 or 7:5, or the volume ratio of aqua regia and deionized water in the aqua regia solution can also be within the range between any two of the above volume ratios.

[0064] In some of the embodiments, the volume ratio of the mass of the silicon-based electrode material to be tested to the aqua regia solution is 1 g:8 mL to 1 g:12 mL.

[0065] Within the above-mentioned range of the mass ratio of the silicon-based electrode material to be tested and the volume ratio of the aqueous regia solution, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the mass ratio of the silicon-based electrode material to be tested and the volume ratio of the aqueous regia solution is 1g:8mL, 1g:9mL, 1g:10mL, 1g:11mL or 1g:12mL, or the mass ratio of the silicon-based electrode material to be tested and the volume ratio of the aqueous regia solution can also be within the range between any two of the above ratios.

[0066] In some embodiments, the temperature of the second reaction is 115°C to 125°C.

[0067] In the temperature range of the second reaction, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the temperature of the second reaction is 115°C, 116°C, 117°C, 118°C, 119°C, 120°C, 121°C, 122°C, 123°C, 124°C or 125°C, or the temperature of the second reaction can also be within the range between any two of the above temperatures.

[0068] In some embodiments, the second reaction time is 25 min to 35 min.

[0069] Within the time range of the second reaction, it is convenient to achieve a better extraction effect of silicon in the silicon-based electrode material. Optionally, the time of the second reaction is 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min or 35 min, or the time of the second reaction can also be within the range between any two of the above times.

[0070] In some embodiments, after performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate, the following steps are also included:

[0071] The first solid material is washed with deionized water to obtain a first washing liquid, and the first washing liquid and the first filtrate are mixed.

[0072] In some embodiments, after performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate, the following steps are also included:

[0073] The second solid material is washed with deionized water to obtain a second washing liquid, and the second washing liquid is mixed with the second filtrate.

[0074] In some embodiments, respectively detecting the silicon content in the first filtrate and the second filtrate comprises the following steps:

[0075] The silicon concentrations in the first filtrate and the second filtrate were detected by inductively coupled plasma mass spectrometry.

[0076] It can be understood that the silicon concentration in the first filtrate and the second filtrate can be detected by inductively coupled plasma optical emission spectrometer ICP-OES, that is, by inductively coupled plasma mass spectrometry.

[0077] In some embodiments, detecting the silicon concentration in the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry comprises the following steps:

[0078] Prepare silicon standard solutions of different concentrations;

[0079] The silicon concentration in each silicon standard solution is measured by inductively coupled plasma mass spectrometry to obtain a response value-concentration curve;

[0080] Testing the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry to obtain a first response value of the first filtrate and a second response value of the second filtrate;

[0081] The first response value, the second response value and the response value-concentration curve are compared respectively to obtain the silicon concentration in the first filtrate and the second filtrate.

[0082] In some embodiments, the silicon-based electrode material includes at least one of silicate and composite materials thereof.

[0083] In some embodiments, the silicon-based electrode material includes at least one of lithium orthosilicate and a composite material thereof.

[0084] Another embodiment of the present application provides a detection device for silicon content in a silicon-based electrode material, comprising: a first reaction device, a first solid-liquid separation device, a second reaction device, a second solid-liquid separation device and a detection device. Among them, the first reaction device is used to mix the silicon-based electrode material to be tested with an alkaline solution, and obtain a first slurry through a first reaction. The first solid-liquid separation device is used to perform a first solid-liquid separation treatment on the first slurry to obtain a first solid material and a first filtrate. The second reaction device is used to mix the first solid material and an aqueous regia solution, and obtain a second slurry through a second reaction. The second solid-liquid separation device is used to perform a second solid-liquid separation treatment on the second slurry to obtain a second solid material and a second filtrate. The detection device is used to detect the silicon content in the first filtrate and the second filtrate, respectively, and calculate the silicon content in the silicon-based electrode material according to the silicon content in the first filtrate and the silicon content in the second filtrate.

[0085] Example 1

[0086] Detection method of silicon content in silicon-based electrode materials:

[0087] Weigh 0.1g of lithium orthosilicate composite material, add a small amount of deionized water to moisten it, add 10mL of NaOH solution with a mass concentration of 10%, shake well and heat on a 120℃ hot plate for 180min, filter after cooling, and wash the filter residue with deionized water for 3 times, collect the filtrate, and dilute it to a 100mL polyethylene volumetric flask to obtain an alkali-soluble silicon solution. Transfer the filter residue together with the filter paper to a polytetrafluoroethylene beaker, add deionized water to cover the filter paper, add 2mL of aqua regia solution mixed with aqua regia and deionized water in a volume ratio of 1:1, place it on a 120℃ hot plate and heat it for 30min, remove it and cool it, and dilute it to a 100mL glass volumetric flask to obtain an acid-soluble silicon solution.

[0088] The concentration of silicon in the alkaline and acid-soluble silicon solutions to be tested was detected by inductively coupled plasma emission spectrometry (ICP-OES). The specific detection method is as follows: (1) Preparation of standard solution: Provide a 1000ppm silicon standard solution (China Nonferrous Metals Research Institute), take 5mL of the standard solution, dilute to 50mL, and obtain a 100ppm standard stock solution. Use 0.1% sodium carbonate solution to dilute the stock solution step by step to obtain 0.5ppm, 1ppm, 2ppm, 5ppm, 10ppm, and 20ppm silicon standard solutions. (2) Equipment parameter setting: Equipment model: ICAP 7000, power: 1150W, nebulizer flow: 0.5L / min, auxiliary gas flow: 0.5L / min, delay time: 40s, select 251.611nm as the analysis wavelength. (3) Test the noble concentration of each silicon standard solution to obtain a response value-concentration curve. According to the response value-concentration curve, the concentration of silicon in the alkali-soluble silicon solution and the acid-soluble silicon is obtained respectively, and the silicon content in the lithium orthosilicate composite material can be obtained by adding the two silicon contents.

[0089] Comparative Example 1

[0090] At present, the determination of the main components and doping metal content of lithium orthosilicate composite materials for electrodes mainly refers to GB / T14506.3-2010 Chemical Analysis Methods for Silicate Rocks.

[0091] Detection method of silicon content in silicon-based electrode materials:

[0092] Weigh 1g of lithium orthosilicate composite material, place it in a Perkin crucible pre-filled with 6g of anhydrous sodium carbonate powder, stir evenly, then cover it with 1g of anhydrous sodium carbonate, cover the platinum crucible lid, put it in a high-temperature furnace, melt it at 1000℃ for 40min, and cool it down and take it out. Put the cooled platinum crucible into a 250ml beaker, slowly add 50mL of dilute hydrochloric acid with a volume ratio of 1:1, and after the violent reaction stops, heat it to make the frit fall off, wash out the crucible, put the beaker in a boiling water bath, evaporate it to about 10mL, remove it, add 20ml of hydrochloric acid, put the beaker in a 70℃ water bath, add 10ml of animal gel, stir evenly, add water to 40ml after 10min, stir to dissolve the salts, filter, and wash the filter residue until there is no chloride ion, put the filter paper together with the filter residue into the platinum crucible, after low-temperature ashing, place it in a high-temperature furnace at 1000℃ and burn it for 1h, weigh it, and then repeatedly burn it for 30min until constant weight. Add 3 drops of water along the crucible wall to moisten the precipitate, add 10d sulfuric acid and 5ml hydrofluoric acid, heat until the white smoke disappears, place the crucible in a 1000℃ high-temperature furnace and burn for 30min, weigh it after cooling, and then repeatedly burn for 30min to constant weight. The difference between the two weights is the silica content in the precipitate. The residue in the crucible was melted with 1g potassium pyrosulfate in a high-temperature furnace at 700℃ for 5min, a small amount of deionized water was added to cover the residue, and 5 drops of hydrochloric acid were added, heated to dissolve, filtered, and the filtrate was added to the filtrate obtained by the first filtration, and the volume was adjusted to 250ml. 10ml of the filtrate was placed in a 50ml polytetrafluoroethylene beaker, 10ml of sodium hydroxide solution (concentration 100g / L) was added, heated and boiled for 10min, and after cooling, 1 drop of phenolphthalein indicator was added, and the solution was neutralized with hydrochloric acid until the red color faded and 6ml was in excess, and the volume was adjusted to 100ml. The solution was transferred to a conical flask, 10mL of ethanol and 5mL of ammonium molybdate solution were added, and after standing for 20min, 10mL of dilute sulfuric acid was added, and after shaking for 5min, 5mL of ascorbic acid was added. After standing for 1h, the absorbance was measured at a wavelength of 660nm on a spectrophotometer, and compared with a silica solution of a standard concentration to calculate the content of silica in the filtrate. The sum of the silica contents in the filter residue and the filtrate is the total amount of silica in the sample, which is converted into the total silicon content.

[0093] Comparative Example 2

[0094] The samples were extracted and tested with reference to the national standard GB / T 14506.31-2019 Chemical analysis method of silicate rocks lithium metaborate melting-inductively coupled plasma atomic emission spectrometry.

[0095] Detection method of silicon content in silicon-based electrode materials:

[0096] Weigh 0.1g of lithium orthosilicate composite material, place it in a graphite crucible containing 0.4g of anhydrous lithium metaborate, stir evenly, cover it with a lid and place it in a high-temperature furnace at 1000℃, melt for 15min, remove it and cool it, then place the graphite crucible in a beaker containing 30mL of aqua regia with a volume ratio of 1:1, place the beaker in an ultrasonic cleaner, and add deionized water to the beaker to cover the graphite crucible, ultrasonically dissolve the molten salt for 15min, wash out the graphite crucible, and dilute the solution in the beaker to 50mL, which is the sample solution to be tested. The concentration of silicon in the solution to be tested is detected by inductively coupled plasma emission spectrometry ICP-OES. The specific detection method is as follows: (1) Preparation of standard solution: Provide a 1000ppm silicon standard solution (China Nonferrous Metals Research Institute), take 5mL of the standard solution, dilute to 50mL, and obtain a 100ppm standard stock solution. The stock solution was diluted step by step with 0.1% sodium carbonate solution to obtain 0.5ppm, 1ppm, 2ppm, 5ppm, 10ppm, and 20ppm silicon standard solutions. (2) Equipment parameter setting: Equipment model: ICAP 7000, power: 1150W, atomizer flow: 0.5L / min, auxiliary gas flow: 0.5L / min, delay time: 40s, and select 251.611nm as the analysis wavelength. (3) The silicon concentration of each silicon standard solution was tested to obtain a response value-concentration curve. According to the response value-concentration curve, the silicon concentration in the alkaline-soluble silicon solution and the acid-soluble silicon solution was obtained respectively. The silicon content in the lithium orthosilicate composite material was obtained by adding the two silicon contents.

[0097] Test Example 1

[0098] The five different samples were tested by the method for detecting the silicon content in the silicon-based electrode material in Example 1, and the sample 1# was tested by the method for detecting the silicon content in the silicon-based electrode material in Comparative Example 1 and Comparative Example 2. The test results are shown in the following table:

[0099]

[0100] The test data show that there is little difference in silicon content obtained by the extraction methods in Example 1 and Comparative Example 1. The silicon content obtained by the method for detecting the silicon content in the silicon-based electrode material in Comparative Example 2 is significantly lower than that in Example 1 and Comparative Example 1, indicating that the method for detecting the silicon content in the silicon-based electrode material in Comparative Example 2 is not effective for the silicon extraction method.

[0101] Test Example 2

[0102] The silicon extraction rate of the five samples in Test Example 1 was measured.

[0103] Weigh 0.1g lithium orthosilicate composite material sample in a polytetrafluoroethylene beaker, weigh 0.02g high-purity silicon powder (99.99%), add it to the polytetrafluoroethylene beaker containing the sample, add a small amount of deionized water to moisten, add 20mL of 10% NaOH solution, shake well and heat on a 120℃ hot plate for 180min, filter after cooling, and wash the filter residue with deionized water 3 times, collect the filtrate, and dilute to a 100mL polyethylene volumetric flask to obtain an alkali-soluble silicon solution. Transfer the filter residue together with the filter paper to a polytetrafluoroethylene beaker, add deionized water to cover the filter paper, add 4mL of aqua regia with a volume ratio of 1:1, place on a 120℃ hot plate and heat for 30min, remove and cool, and dilute to a 100mL glass volumetric flask to obtain an acid-soluble silicon solution. The concentration of silicon in the alkaline silicon solution and the acid silicon solution to be tested is detected by inductively coupled plasma emission spectrometer ICP-OES. According to the response value-concentration curve, the concentration of silicon in the alkaline silicon solution and the acid silicon solution is obtained respectively. The silicon content in the lithium orthosilicate composite material can be obtained by adding the two silicon contents. The specific data are as follows:

[0104]

[0105] Through the test method of directly adding high-purity silicon powder to the sample, the detection method of silicon content in silicon-based electrode materials of the present application can be used to test the extraction rate of silicon in the silicon-based electrode materials to be tested. As can be seen from the above table, the extraction rate of silicon in different silicon-based electrode materials to be tested by the detection method of silicon content in silicon-based electrode materials of the present application can reach more than 99%. That is, the detection method of silicon content in silicon-based electrode materials of the present application has a better effect on the extraction of silicon from silicon-based electrode materials. Compared with the detection method of silicon content in silicon-based electrode materials in Comparative Example 1, the silicon extraction rate of Example 1 is equivalent, but the operation steps are simplified.

[0106] Test Example 3

[0107] Sample 1# was repeatedly tested for silicon content in silicon-based electrode materials using the method for testing silicon content in Example 1. The test results are shown in the following table:

[0108]

[0109] It can be seen that the same sample was repeatedly tested multiple times using the method for detecting the silicon content in the silicon-based electrode material of the present application, and the relative standard deviation was less than 1%, indicating that the test results of the method for detecting the silicon content in the silicon-based electrode material of the present application have high repeatability and small errors in the test results.

[0110] 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.

[0111] The above-mentioned embodiments only express several implementation methods 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 a person 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. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description may be used to interpret the content of the claims.

Claims

1. A method for detecting silicon content in a silicon-based electrode material, characterized in that: The steps include: Mixing the silicon-based electrode material to be tested with an alkaline solution, and performing a first reaction to obtain a first slurry; Performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate; The first solid material and the aqueous regia solution are mixed and subjected to a second reaction to obtain a second slurry; performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate; The silicon contents in the first filtrate and the second filtrate are detected respectively, and the silicon content in the silicon-based electrode material is calculated according to the silicon content in the first filtrate and the silicon content in the second filtrate.

2. The method for detecting silicon content in a silicon-based electrode material according to claim 1, characterized in that: The solute of the alkali solution includes at least one of sodium hydroxide and potassium hydroxide; and / or, The mass concentration of the solute in the alkali solution is 5% to 20%; and / or, The mass ratio of the silicon-based electrode material to be tested to the solute in the alkali solution is 1:(8-12).

3. The method for detecting silicon content in a silicon-based electrode material according to claim 1, characterized in that: The temperature of the first reaction is 115°C to 125°C; and / or, The first reaction time is 160 min to 200 min.

4. The method for detecting silicon content in a silicon-based electrode material according to claim 1, characterized in that: The volume ratio of aqua regia and deionized water in the aqua regia solution is (3-7):5; and / or, The mass ratio of the silicon-based electrode material to be tested to the volume ratio of the aqua regia solution is 1 g:8 mL to 1 g:12 mL.

5. The method for detecting silicon content in silicon-based electrode materials according to claim 1, characterized in that: The temperature of the second reaction is 115°C to 125°C; and / or, The time of the second reaction is 25min~35min.

6. The method for detecting silicon content in a silicon-based electrode material according to claim 1, characterized in that: After performing a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate, the following steps are also included: Washing the first solid material with deionized water to obtain a first washing liquid, and mixing the first washing liquid with the first filtrate; and / or, After performing a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate, the following steps are also included: The second solid material is washed with deionized water to obtain a second washing liquid, and the second washing liquid and the second filtrate are mixed.

7. The method for detecting silicon content in a silicon-based electrode material according to claim 1, characterized in that: The steps of detecting the silicon content in the first filtrate and the second filtrate respectively include: The silicon concentrations in the first filtrate and the second filtrate are respectively detected by inductively coupled plasma mass spectrometry.

8. The method for detecting silicon content in silicon-based electrode materials according to claim 7, characterized in that: Detecting the silicon concentration in the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry comprises the following steps: Prepare silicon standard solutions of different concentrations; The silicon concentration in each silicon standard solution is measured by inductively coupled plasma mass spectrometry to obtain a response value-concentration curve; Testing the first filtrate and the second filtrate respectively by inductively coupled plasma mass spectrometry to obtain a first response value of the first filtrate and a second response value of the second filtrate; The first response value, the second response value and the response value-concentration curve are compared respectively to obtain the silicon concentration in the first filtrate and the second filtrate.

9. The method for detecting silicon content in a silicon-based electrode material according to any one of claims 1 to 8, characterized in that: The silicon-based electrode material includes at least one of lithium orthosilicate and a composite material thereof.

10. A device for detecting silicon content in a silicon-based electrode material, characterized in that: include: A first reaction device, a first solid-liquid separation device, a second reaction device, a second solid-liquid separation device and a detection device; wherein, The first reaction device is used to mix the silicon-based electrode material to be tested with an alkaline solution, and obtain a first slurry through a first reaction; The first solid-liquid separation device is used to perform a first solid-liquid separation process on the first slurry to obtain a first solid material and a first filtrate; The second reaction device is used to mix the first solid material and the aqueous regia solution, and obtain a second slurry through a second reaction; The second solid-liquid separation device is used to perform a second solid-liquid separation process on the second slurry to obtain a second solid material and a second filtrate; The detection device is used to detect the silicon content in the first filtrate and the second filtrate respectively, and calculate the silicon content in the silicon-based electrode material according to the silicon content in the first filtrate and the silicon content in the second filtrate.

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