Method for detecting content of methylene methanedisulfonate in lithium ion battery electrolyte
By performing water bath heating pretreatment and ion chromatography detection on the lithium-ion battery electrolyte, the problem of inaccurate detection of methylene methane disulfonate content in the prior art is solved, and higher measurement accuracy and accuracy are achieved.
Patent Information
- Application Number
- CN202411430770.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2025-01-07
AI Technical Summary
Existing methods When detecting methane disulfonate content in lithium-ion battery electrolyte, gas chromatography has low response and super-inductive coupled plasma emission spectrometry has limitations on the testing of sulfur-containing electrolytes. Ion chromatography Method test results are often lower than the theoretical value, and accurate quantitative measurement cannot be achieved.
The lithium-ion battery electrolyte sample was pretreated, including dilution and water bath heating, and the temperature was controlled at 70-80°C, with a time of 80-100 minutes. After cooling, the hydrolysis of methane disulfonate was detected by ion chromatography. The content of methylene disulfonate ions is used as the leachate solution, and the separation column and the inhibitory column are used in combination. The leachate contains chromatographic acetonitrile and ultrapure water.
Improve measurement accuracy, ensure complete hydrolysis of methane disulfonate and avoid excessive decomposition, the ion chromatography detection results are more accurate, and can achieve accurate quantification of methane disulfonate content in lithium-ion battery electrolyte test.
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Figure CN119269706A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lithium ion batteries, and in particular to a method for detecting the content of methylene methane disulfonate in an electrolyte of a lithium ion battery. Background Art
[0002] Methylene disulfonate (MMDS, chemical formula: C2H4O6S2, CAS number: 99591-74-9), as an additive, is increasingly used in lithium-ion battery electrolytes to give the battery better high-temperature cycle performance. In order to accurately measure the content of additives in lithium-ion electrolytes, the commonly used methods are gas chromatography, ultra-inductively coupled plasma optical emission spectrometry, and ion chromatography. Among them: gas chromatography (GC) has a low response to MMDS, and the test accuracy and repeatability are poor; ultra-inductively coupled plasma optical emission spectrometry (ICP-OES) has limitations for testing electrolytes containing sulfur; ion chromatography (IC) has a wide test coverage and can meet the test of various formulas, but the test results are always lower than the theoretical value, and the content of MMDS in lithium-ion battery electrolytes cannot be accurately quantitatively tested. Summary of the invention
[0003] In order to solve the above technical problems, the present invention provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte, and the measurement accuracy is improved by pre-treating the electrolyte before testing.
[0004] The present invention adopts the following technical solutions:
[0005] A method for detecting the content of methylene disulfonate in a lithium ion battery electrolyte comprises a pretreatment step of diluting a lithium ion battery electrolyte sample containing methylene disulfonate, heating the diluted solution in a water bath at 70-80°C, and cooling.
[0006] Furthermore, the water bath heating time is 80 to 100 minutes.
[0007] Furthermore, the lithium ion battery electrolyte sample containing methylene methane disulfonate is diluted 100 to 400 times.
[0008] Furthermore, the lithium ion battery electrolyte sample containing methylene methane disulfonate is diluted 100 to 400 times with ultrapure water.
[0009] Furthermore, the cooling process includes cooling in a water bath at room temperature.
[0010] Furthermore, the method for detecting the content of methylene disulfonate in a lithium ion battery electrolyte comprises the following steps:
[0011] (1) Pre-treating the lithium-ion battery electrolyte: diluting a lithium-ion battery electrolyte sample containing methylene disulfonate, heating the diluted solution in a water bath at 70 to 80° C., and cooling;
[0012] (2) The content of methylene disulfonate ion generated by hydrolysis of methylene methane disulfonate was detected by ion chromatography.
[0013] Furthermore, the detection conditions adopted by the ion chromatography include: the separation column adopts a solution containing Na2CO3 and NaHCO3 as eluent.
[0014] Furthermore, the detection conditions include: analytical column A Supp 5; guard column A Supp 4 / 5Guard; suppression column MSM.
[0015] Furthermore, the concentrations of the eluents are: 3.2 mmol / L for Na2CO3 and 1 mmol / L for NaHCO3.
[0016] Furthermore, the eluent also includes 40% by volume of chromatography-grade acetonitrile and 60% by volume of ultrapure water.
[0017] The method for detecting the content of methylene disulfonate in a lithium ion battery electrolyte of the present invention performs water bath heating pretreatment on the electrolyte before detection and controls the water bath temperature, thereby ensuring that the methylene disulfonate is hydrolyzed completely as much as possible and avoiding more decomposition, so that the result of detection by ion chromatography is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0019] Figure 1 is the ion chromatogram of Examples 1-7 of the present invention;
[0020] Figure 2 It is the ion chromatogram of Example 1 and Comparative Examples 1-6 of the present invention. DETAILED DESCRIPTION
[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.
[0022] In the present invention, the CAS number of methylene disulfonate is 99591-74-9, the molecular formula is C2H4O6S2, the molecular weight is about 188.17, and the Chinese aliases of methylene disulfonate include: 1,5,2,4-dioxadithiane-2,2,4,4-tetraoxide, methylene disulfonate, methylene disulfonate; English name: Methylenemethanedisulfonate, referred to as MMDS; English alias: 1,5,2,4-dioxadithiane-2,2,4,4-tetraoxide. Generally, the purity of commercially available methylene disulfonate is ≥99.0%, and its properties are white or off-white crystals or crystalline powders, and the melting point is 146.0-146.5°C.
[0023] The invention provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte, comprising a pretreatment step of diluting a lithium ion battery electrolyte sample containing methylene methane disulfonate, heating the diluted solution in a water bath at 70-80°C, and cooling.
[0024] In the process of determining the content of methylene disulfonate in the electrolyte of lithium-ion batteries, the methylene disulfonate ion, the hydrolysis product of methylene disulfonate, is used as the test standard to obtain the content of methylene disulfonate. If the standard is to be measured, it is necessary to handle the relationship between the hydrolysis and decomposition of methylene disulfonate, and ensure that it is hydrolyzed as completely as possible but not allowed to decompose too much. After a large number of creative experiments, the researchers found that when the temperature is below 70°C, methylene disulfonate cannot be completely hydrolyzed, and the test results are low; when the temperature is above 80°C, the structure of methylene disulfonate is destroyed, there is more decomposition, and the test results will also be low. When the water bath heating temperature is between 70 and 80°C, complete hydrolysis can be achieved while avoiding more decomposition, and the measurement results are the most accurate.
[0025] Specifically, as an embodiment of the present invention, the water bath heating time is 80 to 100 minutes. Preferably, the water bath heating time is 90 minutes.
[0026] Specifically, as an embodiment of the present invention, a lithium ion battery electrolyte sample containing methylene methanedisulfonate is diluted 100 to 400 times.
[0027] Specifically, as an embodiment of the present invention, a lithium ion battery electrolyte sample containing methylene methanedisulfonate is diluted 100 to 400 times with ultrapure water.
[0028] Specifically, as an embodiment of the present invention, the cooling process includes cooling in a normal temperature water bath.
[0029] Specifically, as an embodiment of the present invention, the method for detecting the content of methylene disulfonate in a lithium ion battery electrolyte comprises the following steps:
[0030] (1) Pre-treating the lithium-ion battery electrolyte: diluting a lithium-ion battery electrolyte sample containing methylene disulfonate, heating the diluted solution in a water bath at 70 to 80° C., and cooling;
[0031] (2) The content of methylene disulfonate ion generated by hydrolysis of methylene methane disulfonate was detected by ion chromatography.
[0032] Specifically, as an embodiment of the present invention, the detection conditions adopted by the ion chromatography method include: the separation column uses a solution containing Na2CO3 and NaHCO3 as an eluent. Preferably, in the eluent, the concentration of Na2CO3 is 3.2mmol / L, and the concentration of NaHCO3 is 1mmol / L. The eluent also includes 40% by volume of chromatographic grade acetonitrile and 60% by volume of ultrapure water.
[0033] More specifically, the preparation process of the eluent includes: accurately weighing 400 mL of chromatographic grade acetonitrile using an analytical balance, adding ultrapure water to 1 L, shaking well and setting aside. Accurately pipetting 6.4 mL of 0.5 mol / L Na2CO3 and 2.0 mL of 0.5 mol / L NaHCO3 into the above prepared solution. After covering the lid, shaking well, filtering with a 0.45 μm water-oil two-phase membrane, and placing the eluent bottle in an ultrasonic instrument for ultrasonic treatment for 15 minutes to remove bubbles in the solution to obtain the eluent.
[0034] Specifically, as an embodiment of the present invention, the detection conditions include: analytical column A Supp 5 (4×250 mm); guard column A Supp 4 / 5Guard; suppression column MSM. The column temperature is 40° C.
[0035] The present invention will be further described below in conjunction with specific embodiments.
[0036] Example 1
[0037] (1) The test equipment and conditions of this embodiment are as follows:
[0038] Swiss Metrohm 831 ion chromatograph, MetrosepA Supp 5-150 / 4.0 anion separation column, eluent is a mixture of 3.2mmol Na2CO3+1.0mmol NaHCO3+40vol% acetonitrile+60vol% ultrapure water, flow rate is 0.7mL / min, column temperature is 40℃, conductivity cell temperature is 40℃. Standard reagents (methylene disulfonate standard sample) and Na2CO3, NaHCO3 are all products of Aladdin (Shanghai Aladdin Biochemical Technology Co., Ltd.), and experimental water is 18.2MΩ×cm secondary deionized water. The length of the chromatographic column is 150mm, the inner diameter is 4.0mm, and the injection volume is 250μL each time.
[0039] (2) Sample pretreatment:
[0040] Use an analytical balance (accuracy 0.0001g) to weigh 0.2500g of electrolyte sample, dilute it to 50.00g (accurate to 0.0001g) with ultrapure water, and then heat the sample in a 75℃ water bath for 90min. After heating, take it out and soak it in a large beaker filled with ultrapure water at room temperature to cool it down to obtain the sample to be tested.
[0041] (3) Preparation and testing of standard solutions
[0042] Preparation of mother solution: prepare a dimethyl carbonate (DMC) solution with a concentration equivalent to that of methylene methanedisulfonate (MMDS) in the electrolyte sample, recorded as MMDS mother solution (the aforementioned masses are all accurate to 0.0001 g).
[0043] Weigh 0.1250g MMDS mother liquor, dilute it to 50.00g with ultrapure water, and record it as standard solution 1; weigh 0.2500g MMDS mother liquor, dilute it to 50.00g with ultrapure water, and record it as standard solution 2; weigh 0.5000g MMDS mother liquor, dilute it to 50.00g with ultrapure water, and record it as standard solution 3; after shaking well, test it with an ion chromatograph, and draw a standard curve with the concentration content of MMDS as the horizontal axis and the corresponding peak area as the vertical axis.
[0044] (4) Test samples
[0045] The sample to be tested that has been pre-treated in step (2) is tested using an ion chromatograph; the MMDS concentration in the sample to be tested is measured based on the standard curve.
[0046] Example 2
[0047] This embodiment provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte. Compared with Embodiment 1, the only difference is that in the sample pretreatment, the sample is placed in a 70° C. water bath and heated for 90 minutes.
[0048] Example 3
[0049] This embodiment provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte. Compared with Embodiment 1, the only difference is that in the sample pretreatment, the sample is placed in a water bath at 80° C. and heated for 90 minutes.
[0050] Example 4
[0051] This embodiment provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte. Compared with Embodiment 1, the only difference is that in the sample pretreatment, the sample is placed in a 75° C. water bath and heated for 80 minutes.
[0052] Example 5
[0053] This embodiment provides a method for detecting the content of methylene methanedisulfonate in a lithium-ion battery electrolyte. Compared with Embodiment 1, the only difference is that, in the sample pretreatment, the sample is placed in a 75° C. water bath and heated for 100 minutes.
[0054] Example 6
[0055] This embodiment provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte. Compared with Embodiment 1, the only difference is that in the sample pretreatment, the sample is placed in a 75° C. water bath and heated for 120 minutes.
[0056] Example 7
[0057] This embodiment provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte. Compared with Embodiment 1, the only difference is that in the sample pretreatment, the sample is placed in a 75° C. water bath and heated for 60 minutes.
[0058] Comparative Example 1
[0059] This comparative example provides a method for detecting the content of methylene disulfonate in a lithium ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, no water bath heating is performed, and only dilution is performed; specifically:
[0060] Use an analytical balance (accuracy 0.0001g) to weigh 0.2500g of electrolyte sample, dilute it to 50.00g (accurate to 0.0001g) with ultrapure water, and obtain the sample to be tested.
[0061] Comparative Example 2
[0062] This comparative example provides a method for detecting the content of methylene methane disulfonate in a lithium ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, water bath heating is not performed, and the sample is left to stand after dilution; specifically:
[0063] Use an analytical balance (accuracy 0.0001g) to weigh 0.2500g of electrolyte sample, dilute it to 50.00g (accurate to 0.0001g) with ultrapure water, shake it well and let it stand for 90min to obtain the sample to be tested.
[0064] Comparative Example 3
[0065] This comparative example provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, the sample is placed in a 60° C. water bath and heated for 90 minutes.
[0066] Comparative Example 4
[0067] This comparative example provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, the sample is placed in a 68° C. water bath and heated for 90 minutes.
[0068] Comparative Example 5
[0069] This comparative example provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, the sample is placed in a water bath at 82° C. and heated for 90 minutes.
[0070] Comparative Example 6
[0071] This comparative example provides a method for detecting the content of methylene disulfonate in a lithium-ion battery electrolyte. Compared with Example 1, the only difference is that in the sample pretreatment, the sample is placed in a 90° C. water bath and heated for 90 minutes.
[0072] In each embodiment and comparative example, MMDS content test was performed on 5 parallel samples of the same electrolyte sample continuously, and the test results are shown in Table 1.
[0073] Electrolyte sample: EC 20wt%; EMC 25wt%; DMC 41.5wt%; VC 2.5wt%; FEC 0.7wt%; MMDS 0.3wt%; LiPF6 10wt%.
[0074] Table 1
[0075]
[0076] From Table 1 and Figure 1-2It can be seen from the test results of Examples 1-7 and Comparative Examples 1-6 that, compared with the conventional method of direct detection after dilution or detection after dilution and standing, by pre-treating the electrolyte with water bath heating and controlling the water bath temperature before detection, the hydrolysis of methylene disulfonate can be ensured to be complete as much as possible, and more decomposition can be avoided, so that the results of detection by ion chromatography are more accurate. At the same time, for the water bath heating temperature, when the temperature is below 70°C, methylene disulfonate cannot be completely hydrolyzed, and the test results are low; when the temperature is above 80°C, the structure of methylene disulfonate is destroyed, there is more decomposition, and the test results will also be low. When the water bath heating temperature is 70-80°C, complete hydrolysis can be achieved and more decomposition can be avoided, and the measurement results are the most accurate. At the same time, when the water bath heating time is 80-100min, the accuracy of the measurement results is higher.
[0077] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description here should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in the field after reading this specification are all within the scope of protection of the present invention.
Claims
1. A method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte, characterized in that: The method comprises the following pretreatment steps: diluting a lithium ion battery electrolyte sample containing methylene disulfonate, heating the diluted solution in a water bath at 70-80° C., and cooling the solution.
2. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 1, characterized in that the water bath heating time is 80 to 100 minutes.
3. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 1, characterized in that: A lithium-ion battery electrolyte sample containing methylene methanedisulfonate was diluted 100 to 400 times.
4. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 1 or 3, characterized in that: A lithium-ion battery electrolyte sample containing methylene methanedisulfonate was diluted 100 to 400 times with ultrapure water.
5. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 1, characterized in that: The cooling process includes cooling in a water bath at room temperature.
6. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 1, characterized in that: The following steps are involved: (1) Pre-treating the lithium-ion battery electrolyte: diluting a lithium-ion battery electrolyte sample containing methylene disulfonate, heating the diluted solution in a water bath at 70 to 80° C., and cooling; (2) The content of methylene disulfonate ion generated by hydrolysis of methylene methane disulfonate was detected by ion chromatography.
7. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 6, characterized in that: The detection conditions adopted by the ion chromatography method include: the separation column adopts a solution containing Na2CO3 and NaHCO3 as eluent.
8. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 6, characterized in that: The detection conditions include: analytical column A Supp 5; guard column A Supp 4 / 5Guard; suppression column MSM.
9. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 7, characterized in that: The concentrations of the eluent are: Na2CO3 is 3.2mmol / L, and NaHCO3 is 1mmol / L.
10. The method for detecting the content of methylene methanedisulfonate in a lithium ion battery electrolyte according to claim 7, characterized in that: The eluent includes 40% by volume of chromatographic grade acetonitrile and 60% by volume of ultrapure water.