Method for testing sulfide solid electrolyte and solid-state battery
By using ammonia water to dissolve and control the pH value, combined with ICP-OES and ion chromatography, the accuracy problem of measuring the element content of sulfide solid electrolytes was solved, the complex operation and high cost problems in the existing technology were simplified, and the accuracy and efficiency of the measurement results were improved.
Patent Information
- Application Number
- CN202510861227.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-23
AI Technical Summary
The existing technology lacks an accurate method for determining the element content of sulfide solid electrolytes. In particular, there is a deviation in the determination of sulfur elements, and traditional methods are complex to operate and costly.
Ammonia water was used to dissolve the sulfide solid electrolyte sample, and the pH value was controlled at 10-12. ICP-OES was used to determine the content of lithium, phosphorus, and sulfur elements, and ion chromatography was used to determine the content of chlorine and bromine elements, thus simplifying the operation process.
A simple and accurate method for determining the element content of sulfide solid electrolytes is provided, which reduces the amount of reagents used and the risk of equipment damage, and improves the accuracy and efficiency of the determination results.
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Figure CN120685622A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of battery testing, and in particular to a testing method for a sulfide solid electrolyte and a solid-state battery. Background Art
[0002] Due to their long service life and high energy density, lithium-ion batteries are often used as power batteries for vehicles. However, in recent years, safety accidents related to lithium-ion batteries have occurred frequently, and the energy density is also approaching its limit. The main reason for the frequent safety accidents related to lithium-ion batteries is that the electrolyte used in traditional liquid lithium-ion batteries is an organic solvent, which is prone to fire, spontaneous combustion and explosion. Therefore, academia and industry have turned to the research of solid batteries, trying to replace flammable electrolytes with non-flammable solid electrolytes to fundamentally improve the safety of batteries and achieve longer driving range.
[0003] Sulfide solid electrolytes have high ionic conductivity, good mechanical properties and interface compatibility, which can significantly improve the charge and discharge efficiency and energy density of batteries. They are considered to be one of the most competitive solid electrolyte materials.
[0004] At present, there is no public test standard for the determination of the main element content of sulfide solid electrolytes, especially the determination of sulfur. If acid digestion is used directly, the sulfur element will form hydrogen sulfide gas and dissipate, resulting in a large deviation in the sulfur content test. Public reports have first used alkaline and oxidizing reagents to convert sulfur into sulfate ions, and then acidified the solution and used inductively coupled plasma optical emission spectrometry (ICP-OES) for testing to avoid strong alkaline solutions damaging the ICP-OES equipment. The traditional chemical titration method requires a large amount of reagents, is complex to operate, and is greatly affected by human factors. Summary of the Invention
[0005] The purpose of the present invention is to overcome the deficiencies and defects of the prior art and to provide a testing method for a sulfide solid electrolyte and a solid-state battery.
[0006] In order to achieve the above objectives, this application adopts the following solutions:
[0007] A method for testing a sulfide solid electrolyte comprises the following steps: 1) adding a sulfide solid electrolyte sample to be tested into a sealed container and adding ammonia water to dissolve the sample to obtain a solution; 2) testing the element content in the solution; and 3) determining the type of the sulfide solid electrolyte based on the content of each element in the solution.
[0008] The sulfide solid electrolyte sample to be tested is Li 7-x PS 6-x N x ; N includes at least one of Cl and Br; 0≤X<6.
[0009] The mass concentration of the ammonia water is 0.1%-5%.
[0010] The pH of the solution is 10-12, preferably 11-12.
[0011] ICP-OES was used to determine the contents of lithium, phosphorus and sulfur in the solution.
[0012] The solution was tested for chlorine and bromine using an ion chromatograph.
[0013] The solution after adding ammonia solution was allowed to stand for 4 h before subsequent element testing.
[0014] The mass of the sulfide solid electrolyte sample to be tested is 0.1-0.2 g, preferably 0.15 g.
[0015] The sealed container is a headspace bottle, and the volume of the headspace bottle is 20 ml.
[0016] The present invention also includes a solid-state battery, comprising a positive electrode sheet, a negative electrode sheet, and an electrolyte layer; the electrolyte layer comprises a sulfide solid electrolyte determined by the test method.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] The present invention provides a method for digesting sulfide solid electrolytes and determining their elemental content. Using simple reagents and equipment, the elemental content can be tested after simple sample treatment, saving significant time and cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1-5 These are the standard curves for lithium, sulfur, phosphorus, chlorine, and bromine in the examples of the present invention. DETAILED DESCRIPTION
[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0021] Example 1:
[0022] In order to test the effectiveness of this method, the known sulfide solid electrolyte Li6PS5Cl 0.5 Br 0.5 As a sample, digestion and testing were performed. The ICP-OES instrument was Thermo Fisher iCAP PRO X, and the ion chromatograph was Dionex ICS-1500. The standard curves of each element were as follows: Figure 1-5It is shown that the mass concentration of the element can be directly obtained by measuring the intensity of the instrument according to the standard curve.
[0023] The testing method of sulfide solid electrolyte comprises the following steps:
[0024] Step 1: Add 0.15 g of sulfide solid electrolyte to a 20 mL headspace bottle in a glove box. Seal the bottle cap and remove.
[0025] Step 2: In a fume hood, use a syringe to inject different amounts of concentrated ammonia water with concentrations ranging from 25% to 28% into the headspace bottle. After the solid electrolyte is completely dissolved, transfer the solution to a 1L volumetric flask and adjust the volume to obtain the test sample solution.
[0026] Step 3: Immediately after the above solution treatment is completed, use ICP-OES to test lithium, phosphorus and sulfur elements, and use ion chromatography to test chlorine and bromine elements.
[0027] The operating parameters of the ICP-OES are shown in Table 1 below, the operating parameters of the ion chromatograph are shown in Table 2 below, and the element mass contents corresponding to different amounts of ammonia added are shown in Table 3.
[0028] Table 1
[0029]
[0030] Table 2
[0031]
[0032] Table 3
[0033]
[0034] The results show that according to the digestion and determination method in the embodiment, the amount of ammonia added is 4mL and the pH is 11.25, which can meet the requirements. The results obtained are consistent with the sample Li6PS5Cl 0.5 Br 0.5 The element content and the determination results are accurate.
[0035] Example 2:
[0036] Take 0.15g Li6PS5Cl in the glove box 0.5 Br 0.5 The sulfide solid electrolyte was prepared according to the method of Example 1, with the addition of 4 mL of concentrated aqueous ammonia, and sample treatment and equipment parameter setting were performed. After the treatment, the test was performed. In the third step, the above solution was allowed to stand for different lengths of time, and lithium, phosphorus, and sulfur elements were tested using ICP-OES, and chlorine and bromine elements were tested using ion chromatography.
[0037] The test results of element content in the samples that cannot be left standing for a long time are shown in Table 4 below:
[0038] Table 4
[0039]
[0040]
[0041] The results show that according to the digestion and determination method in the embodiment, the sample was tested within 4 hours after treatment, and the results obtained were consistent with the results of the sample Li6PS5Cl 0.5 Br 0.5 The element content and the determination results are accurate.
[0042] Example 3:
[0043] Take two portions of 0.15gLi6PS5Cl each 0.5 Br 0.5 For the sulfide solid electrolyte, sample processing and equipment parameter setting were performed according to the method of Example 2, and testing was performed immediately after processing was completed.
[0044] The test results of element content in the samples are shown in Table 5 below;
[0045] Table 5
[0046] sample Li (wt%) P (wt%) S (wt%) Cl (wt%) Br (wt%) Sample 1 14.39 10.75 55.27 6.08 13.51 Sample 2 14.50 10.59 55.10 6.20 13.61
[0047] The results show that the element content measured according to the digestion and determination method in the embodiment is consistent with the sample Li6PS5Cl 0.5 Br 0.5 The element content, the determination results are accurate, and the test parallelism is good.
[0048] Example 4:
[0049] This example is a spike recovery verification test, specifically comprising the following steps: 10 mL of the solution of Sample 1 in Example 3 was added to a mixed standard solution of each of the elements Li, P, S, Cl, and Br, and the volume was fixed to 100 mL to obtain a test solution. The concentration of the added standard solutions of Li, P, S, Cl, and Br was 100 mg / L, the addition volume was 10 mL, and the mass of each element added was 1 mg.
[0050] The test solution was tested according to the method of Example 2. The recovery rate was calculated, and the results are shown in Table 6 below:
[0051] Table 6
[0052]
[0053] The results showed that the digestion method and determination method of the present invention had a high recovery rate and accurate detection results.
[0054] The implementation principle of this application takes Li6PS5Cl as an example, and its reaction formula with ammonia water is:
[0055] Li6PS5Cl+8NH3﹒ H2O→Li3PO4+LiCl+4(NH4)2S+Li2S
[0056] This method generates non-volatile sulfides. The alkaline environment inhibits their decomposition into elemental sulfur precipitates, increasing their stability and resulting in a homogeneous, stable solution. Lithium, phosphorus, and sulfur content can be measured using ICP-OES, and the ammonia-based medium does not damage the ICP-OES equipment. Chlorine and bromine content can also be measured using an ion chromatograph.
[0057] In summary, the present invention provides a method for digesting sulfide solid electrolytes and determining their elemental content, which uses simple reagents and equipment and requires only simple sample processing to test the elemental content, thus saving significant time and cost.
[0058] The basic principles, main features and advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.
[0059] The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.
[0060] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A method for testing a sulfide solid electrolyte, characterized in that: The method comprises the following steps: 1) adding a sulfide solid electrolyte sample to be tested into a sealed container and adding ammonia water to dissolve the sample to obtain a solution; 2) testing the element content in the solution; and 3) judging the type of the sulfide solid electrolyte according to the content of each element in the solution.
2. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The sulfide solid electrolyte sample to be tested is Li 7-x PS 6-x N x ; N includes at least one of Cl and Br; 0≤X<6.
3. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The mass concentration of the ammonia water is 0.1%-5%.
4. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The pH of the solution is 10-12, preferably 11-12.
5. The method for testing a sulfide solid electrolyte according to claim 1, wherein: ICP-OES was used to determine the contents of lithium, phosphorus and sulfur in the solution.
6. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The solution was tested for chlorine and bromine using an ion chromatograph.
7. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The solution after adding ammonia solution was allowed to stand for 4 h before subsequent element testing.
8. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The mass of the sulfide solid electrolyte sample to be tested is 0.1-0.2 g, preferably 0.15 g.
9. The method for testing a sulfide solid electrolyte according to claim 1, wherein: The sealed container is a headspace bottle; the volume of the headspace bottle is 20 ml.
10. A solid-state battery, characterized in that: It comprises a positive electrode sheet, a negative electrode sheet and an electrolyte layer; the electrolyte layer comprises a sulfide solid electrolyte determined by the test method according to any one of claims 1 to 9.