Solid electrolyte membrane and preparation method thereof
By mixing the polymer and sulfide solid electrolyte with ball milling and rolling to form a solid electrolyte film with a skeleton structure, the problem of difficult to prepare a film in the prior art that meets the lightweighting requirements of all-solid sodium batteries is solved, and a high-performance film with a thickness of ≤40μm is achieved.
Patent Information
- Application Number
- CN202311353822.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-18
- Publication Date
- 2025-04-18
AI Technical Summary
It is difficult to prepare a solid electrolyte membrane that meets the lightweighting requirements of all-solid sodium batteries through low-cost methods.
By mixing the polymer and the sulfide solid electrolyte, a skeleton structure is formed, and a solid electrolyte film is obtained by rolling.
The solid electrolyte membrane is thinner and thinner, ensuring good mechanical properties and high ionic conductivity, and can make a high-performance membrane with a thickness of ≤40μm.
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Figure CN119852499A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of solid-state battery technology, and in particular to a solid-state electrolyte membrane and a preparation method thereof. Background Art
[0002] At present, electrochemical energy storage technology is one of the most promising technologies for industrialization among many energy storage technologies due to its advantages such as simplicity, high efficiency, and installation without site restrictions. Among them, lithium-ion batteries have high energy density, long cycle life, high operating voltage, no memory effect, low self-discharge, and are relatively mature. They are the most widely used electrochemical energy storage technology, and have a dominant advantage in the portable electronic device market and electric vehicle power field. They are regarded as the main choice for large-scale energy storage power stations. However, lithium-ion batteries are relatively expensive and global resource reserves are limited. It is impossible to meet the needs of both power batteries and large-scale energy storage for widespread application.
[0003] Sodium and lithium are in the same main group, and their physical and chemical properties are very similar, and their electrode potentials are comparable, so they can be used as substitutes for lithium. At the same time, sodium resources are abundant (the abundance is 4 to 5 orders of magnitude higher than lithium) and the cost is low. Sodium-ion batteries have obvious economic and environmental advantages in the field of large-scale energy storage. On the other hand, the use of inorganic solid electrolytes instead of organic electrolytes can turn the battery into an all-solid-state sodium battery. The battery no longer uses flammable organic solutions, which can simplify safety devices, facilitate production, and reduce the production cost of the battery. In addition, the solid electrolyte is a single sodium ion conductor, in which only sodium ions move, and no side reactions similar to those caused by the movement of anions in the electrolyte will occur. Improvements in safety and durability can be expected.
[0004] Sodium ion solid electrolytes are the key materials for all-solid-state sodium batteries. Among the inorganic solid electrolytes reported so far, sulfide electrolytes have attracted much attention due to their high ionic conductivity and good mechanical properties (easy to eliminate grain boundary resistance).
[0005] In the prior art, technicians have used pulsed laser deposition, vapor deposition and other methods to prepare the corresponding solid electrolyte membrane, but these methods are costly and difficult to truly industrialize. Some people have proposed that the use of sulfide solid electrolyte and polymer composite is an effective solution, but the thickness still cannot fully meet the requirements of thin solid-state sodium batteries. Summary of the invention
[0006] The present application provides a solid electrolyte membrane and a preparation method thereof, so as to achieve lightweight and thin solid electrolyte membrane.
[0007] In a first aspect, the present application provides a method for preparing a solid electrolyte membrane, the method comprising:
[0008] A polymer and a sulfide solid electrolyte are obtained;
[0009] The polymer and the sulfide solid electrolyte are mixed and ball-milled to fiberize the polymer to form a skeleton structure, thereby obtaining a mixture;
[0010] The mixture is roll-pressed to obtain a solid electrolyte membrane.
[0011] As an optional implementation manner, the ball milling time is 1.5 to 2.5 hours.
[0012] As an optional implementation, after the mixed ball milling, the mesh pores of the polymer skeleton structure are non-directional.
[0013] As an optional implementation, the polymer includes at least one of PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride) and PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene).
[0014] As an optional implementation, the mass content of the polymer in the solid electrolyte membrane is 0.1% to 5%.
[0015] As an optional embodiment, the sulfide solid electrolyte includes a sodium ion sulfide solid electrolyte.
[0016] As an optional embodiment, the sodium ion sulfide solid electrolyte includes Na 6-x PS 5-x Cl 1+x and Na 4-x Sn 1-x M x S 4-y O y At least one of .
[0017] As an optional implementation manner, the mass dosage of the sulfide solid electrolyte in the solid electrolyte membrane is 95% to 99.9%.
[0018] In a second aspect, the present application provides a solid electrolyte membrane, which is prepared by the method for preparing the solid electrolyte membrane described in the first aspect.
[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0020] The method provided in the embodiment of the present application realizes the fiberization of the polymer to form a three-dimensional skeleton structure through ball milling, which on the one hand ensures good mechanical properties, and on the other hand is conducive to the formation of a continuous phase of the sulfide solid electrolyte, and better plays the advantage of improving the ionic conductivity of the sulfide solid electrolyte membrane, and can produce a thinner solid electrolyte membrane with good performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0022] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0023] Figure 1 A flowchart of the method provided in the embodiment of the present application. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0026] Figure 1 A flow chart of the method provided in the embodiment of the present application is as follows: Figure 1 As shown, an embodiment of the present application provides a method for preparing a solid electrolyte membrane, the method comprising:
[0027] S1. Obtaining a polymer and a sulfide solid electrolyte;
[0028] In some embodiments, the polymer includes at least one of PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride) and PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene). The polymer has good flexibility and can provide good skeleton support, which is conducive to ensuring the continuity of the sulfide solid electrolyte membrane, so that the sulfide solid electrolyte membrane obtains high ionic conductivity at a very thin thickness. The mass content of the polymer in the solid electrolyte membrane is 0.1% to 5%. Preferably, the mass content is 0.5% to 2%, and more preferably, the mass content is 1%.
[0029] In some embodiments, the sulfide solid electrolyte includes a sodium ion sulfide solid electrolyte. The sodium ion sulfide solid electrolyte includes Na 6-x PS 5-x Cl 1+x and Na 4-x Sn 1-x M x S 4-y O y At least one of the following. The mass dosage of the sulfide solid electrolyte in the solid electrolyte membrane is 95% to 99.9%. Preferably, the mass dosage is 98% to 99.5%, and more preferably, the mass dosage is 99%.
[0030] S2. The polymer and the sulfide solid electrolyte are mixed and ball-milled to form a fiberized skeleton structure of the polymer to obtain a mixture;
[0031] In some embodiments, the ball milling time is 1.5 to 2.5 hours.
[0032] In some embodiments, after the mixed ball milling, the mesh pores of the polymer skeleton structure are non-directional.
[0033] S3. Roll-pressing the mixture to obtain a solid electrolyte membrane.
[0034] This method achieves the fiberization of the polymer membrane to form a three-dimensional skeleton structure through ball milling. On the one hand, it ensures good mechanical properties, and on the other hand, it is conducive to the formation of a continuous phase of the sulfide solid electrolyte and better play the advantage of improving the ionic conductivity of the sulfide solid electrolyte membrane, and can make a thinner solid electrolyte membrane with good performance.
[0035] The ionic conductivity of the solid electrolyte membrane prepared by this method is greater than 10 -4 S / cm, for example, can be 5×10 -4 S / cm, 5.5×10 -4 S / cm, 6×10 -4 S / cm or 10 -3S / cm, etc., the thickness of the solid electrolyte membrane is ≤40μm, for example, it can be 40μm, 35μm, 30μm or 25μm, etc.
[0036] Based on a general inventive concept, an embodiment of the present application further provides a solid electrolyte membrane, which is prepared by the method for preparing the solid electrolyte membrane described in the first aspect.
[0037] The solid electrolyte membrane is prepared based on the above method. The specific steps of the method can refer to the above embodiment. Since the solid electrolyte membrane adopts part or all of the technical solutions of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.
[0038] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.
[0039] Example 1
[0040] A method for preparing a solid electrolyte membrane, the method comprising:
[0041] S1. Obtaining a polymer (granular PTFE (polytetrafluoroethylene)) and a sulfide solid electrolyte (Na6PS5Cl1);
[0042] S2. 0.1 g of the polymer and 9.9 g of the sulfide solid electrolyte were mixed and ball-milled for 2 h to obtain a mixture;
[0043] S3. Roll-press the mixture to obtain a solid electrolyte film.
[0044] The solid electrolyte film provided in Example 1 was assembled into a solid-state battery, and the assembled battery was tested. The results are shown in Table 1.
[0045] Table 1
[0046]
[0047] It can be seen from the above table that the ionic conductivity of the solid electrolyte film prepared by the method provided in the embodiment of the present application is greater than 10 -4 S / cm, and the thickness can be ≤40μm.
[0048] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0049] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.
[0050] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for preparing a solid electrolyte membrane, characterized in that: The method comprises: A polymer and a sulfide solid electrolyte are obtained; The polymer and the sulfide solid electrolyte are mixed and ball-milled to fiberize the polymer to form a skeleton structure, thereby obtaining a mixture; The mixture is roll-pressed to obtain a solid electrolyte membrane.
2. The method for preparing a solid electrolyte membrane according to claim 1, characterized in that: The ball milling time is 1.5 to 2.5 hours.
3. The method for preparing a solid electrolyte membrane according to claim 1 or 2, characterized in that: After the mixed ball milling, the mesh pores of the polymer skeleton structure are non-directional.
4. The method for preparing a solid electrolyte membrane according to claim 1, characterized in that: The polymer includes at least one of PTFE, PVDF and PVDF-HFP.
5. The method for preparing a solid electrolyte membrane according to claim 1 or 4, characterized in that: The mass content of the polymer in the solid electrolyte membrane is 0.1% to 5%.
6. The method for preparing a solid electrolyte membrane according to claim 1, characterized in that: The sulfide solid electrolyte includes a sodium ion sulfide solid electrolyte.
7. The method for preparing a solid electrolyte membrane according to claim 6, characterized in that: The sodium ion sulfide solid electrolyte includes Na 6-x PS 5-x Cl 1+x and Na 4-x Sn 1-x M x S 4-y O y At least one of .
8. The method for preparing a solid electrolyte membrane according to claim 6 or 7, characterized in that: The mass dosage of the sulfide solid electrolyte in the solid electrolyte membrane is 95% to 99.9%.
9. A solid electrolyte membrane, characterized in that: The solid electrolyte membrane is prepared by the method for preparing a solid electrolyte membrane according to any one of claims 1 to 8.