A flexible high-strength solid electrolyte and its preparation method and application

Abstract

The present invention relates to the field of electrochemical technology, and discloses a flexible high-strength solid electrolyte, a preparation method thereof, and an application thereof. The method comprises: (1) heat-treating a raw material powder in the presence of dimethylformamide, and then sintering at 220-250°C to obtain a flexible material; (2) dissolving polyethylene oxide and lithium bis(trifluoromethylsulfonyl)imide in the presence of water to obtain a solution A; (3) contacting a dispersion of the flexible material with the solution A to obtain a flexible high-strength solid electrolyte. The method for preparing a flexible high-strength solid electrolyte provided by the present invention successfully prepares a flexible high-strength solid electrolyte with high ionic conductivity and excellent mechanical strength by rationally selecting raw materials, optimizing material formulations, and precisely controlling the preparation process.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical technology, and in particular to a flexible high-strength solid electrolyte and a preparation method and application thereof. Background Art

[0002] With the rapid development of electric vehicles, wearable devices, mobile communications and other fields, the demand for high-performance, safe and reliable battery technology is growing. However, traditional liquid electrolytes have problems such as flammability, high volatility, and temperature sensitivity, which restrict the safety and stability of batteries. Solid-state electrolytes are safer than traditional liquid electrolytes and are less likely to leak or volatilize, effectively reducing the risk of safety issues such as battery short circuits and overheating. Therefore, the development of a flexible, high-strength solid-state electrolyte with high ionic conductivity and excellent mechanical strength has become one of the current research hotspots in the battery field.

[0003] At present, some preparation methods of solid-state electrolytes have been proposed, but most of them have problems such as complex preparation process, high cost, and insufficient ion conductivity, which make it difficult to meet the needs of actual applications.

[0004] CN116454403A discloses a flexible solid-state lithium battery with high interfacial stability, its preparation method, and its application. This flexible solid-state lithium battery can achieve stable interfacial adhesion under various conditions, such as bending, folding, and winding, as well as stable and rapid ion transport at the interface. However, it suffers from low strain strength, which can lead to a high degree of short circuiting in the event of a collision.

[0005] Therefore, finding a simple, feasible, cost-effective and high-performance solid electrolyte preparation method has become an urgent need in this field, which is expected to make an important contribution to the advancement of battery technology and industrial development. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems of flexible solid electrolytes in the prior art, such as complex preparation process, high cost, low strength and insufficient ion conductivity.

[0007] In order to achieve the above objectives, the first aspect of the present invention provides a method for preparing a flexible high-strength solid electrolyte, the method comprising:

[0008] (1) heat-treating the raw material powder in the presence of dimethylformamide and then sintering it at 220-250° C. to obtain a flexible material;

[0009] (2) dissolving polyethylene oxide and lithium bis(trifluoromethylsulfonyl)imide in the presence of water to obtain solution A;

[0010] (3) contacting the dispersion of the flexible material with the solution A to obtain a flexible high-strength solid electrolyte;

[0011] The raw material powder is composed of NiCl2 and octadecylamine, and in the raw material powder, the weight ratio of the NiCl2 to the octadecylamine is 1:2-3.

[0012] The second aspect of the present invention provides a flexible high-strength solid electrolyte prepared by the method described in the first aspect.

[0013] The third aspect of the present invention provides an application of the flexible high-strength solid electrolyte described in the second aspect in the field of flexible batteries and / or solid-state batteries.

[0014] Compared with the prior art, the method provided by the present invention has at least the following beneficial effects:

[0015] (1) The method provided by the present invention is simple to operate, and the prepared flexible, high-strength solid electrolyte has high chemical stability, can resist the influence of external environmental factors, and prolong the service life and cycle number of the battery;

[0016] (2) The flexible, high-strength solid electrolyte prepared by the method provided by the present invention can be matched with high-capacity positive and negative electrode materials, and can realize battery components with higher energy density, meeting the demand for high energy density in the fields of electric vehicles, mobile communications, etc.

[0017] (3) The flexible properties of the flexible high-strength solid electrolyte prepared by the method provided by the invention make it suitable for flexible electronic products, wearable devices and other fields, and suitable for various application scenarios of flexible batteries and solid-state batteries, thus expanding the application scope of battery technology;

[0018] (4) The flexible high-strength solid electrolyte prepared by the method provided by the invention has higher strength, high ionic conductivity and better mechanical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a SEM image of a flexible high-strength solid electrolyte shown in a preferred embodiment of the present invention;

[0020] Figure 2 This is a stretched physical diagram of a flexible high-strength solid electrolyte shown in a preferred embodiment of the present invention;

[0021] Figure 3 This is a diagram showing the tensile stress intensity and strain of a flexible high-strength solid electrolyte shown in a preferred embodiment of the present invention;

[0022] Figure 4This is an ionic conductivity diagram of a flexible high-strength solid electrolyte shown in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0023] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0024] As mentioned above, the first aspect of the present invention provides a method for preparing a flexible high-strength solid electrolyte, the method comprising:

[0025] (1) heat-treating the raw material powder in the presence of dimethylformamide and then sintering it at 220-250° C. to obtain a flexible material;

[0026] (2) dissolving polyethylene oxide and lithium bis(trifluoromethylsulfonyl)imide in the presence of water to obtain solution A;

[0027] (3) contacting the dispersion of the flexible material with the solution A to obtain a flexible high-strength solid electrolyte;

[0028] The raw material powder is composed of NiCl2 and octadecylamine, and in the raw material powder, the weight ratio of the NiCl2 to the octadecylamine is 1:2-3.

[0029] Preferably, in step (1), the average volume diameter of the raw material powder is 1.5-2.5 mm. Studies have found that under this preferred condition, the morphology of the prepared flexible high-strength solid electrolyte is better.

[0030] Preferably, in step (1), the raw material powder is a product obtained by grinding NiCl2 and octadecylamine using a ball mill and / or a high-energy grinder.

[0031] According to a preferred embodiment, in step (1), the weight ratio of the dimethylformamide to the raw material powder is 3-4:1.

[0032] Preferably, in step (1), the heat treatment conditions at least meet the following requirements: temperature of 60-90° C. and time of 18-24 h.

[0033] Preferably, in step (1), the sintering time is 18-24 hours.

[0034] Preferably, in step (1), the sintering is carried out in a nitrogen atmosphere for 18-24 hours.

[0035] Preferably, in step (2), the polyethylene oxide is in powder form and has a number average molecular weight of 600,000-800,000.

[0036] Preferably, in step (2), the weight ratio of the polyethylene oxide to the lithium bis(trifluoromethylsulfonyl)imide is 10:1-1.5.

[0037] Preferably, in step (2), the dissolving operation includes: first dissolving the polyethylene oxide in deionized water, and then adding the lithium bis(trifluoromethylsulfonyl)imide for second dissolution to obtain the solution A.

[0038] Preferably, the first dissolution and / or the second dissolution is performed under magnetic stirring conditions and at least meets the following conditions: a rotation speed of 500-600 rpm and a time of 60-120 min.

[0039] According to a preferred embodiment, the weight ratio of the polyethylene oxide to the deionized water is 0.05-0.06:1.

[0040] Preferably, in step (3), the weight ratio of the polyethylene oxide in the solution A to the flexible material is 10:1-2. Studies have found that this preferred embodiment can improve the strain strength of the prepared flexible high-strength solid electrolyte.

[0041] Preferably, in step (3), the dispersion of the flexible material is a product obtained by dispersing the flexible material in water, and the concentration of the flexible material in the dispersion of the flexible material is 50-60 wt %.

[0042] Preferably, in step (3), the contact reaction operation includes: adding the dispersion of the flexible material to the solution A to obtain solution B, and then stirring, ultrasonicating, and drying the solution B in sequence to obtain the flexible high-strength solid electrolyte.

[0043] Preferably, in step (3), the operation of the contact reaction includes: stirring the solution B for 0.5-2h, ultrasonicating for 0.5-2h, repeating the stirring and ultrasonicating for at least 1 time, and then drying to a moisture content of no more than 0.01wt% to obtain the flexible high-strength solid electrolyte.

[0044] More preferably, the power of the ultrasound is 200-300 kw.

[0045] As mentioned above, the second aspect of the present invention provides a flexible high-strength solid electrolyte prepared by the method described in the first aspect.

[0046] As mentioned above, the third aspect of the present invention provides the application of the flexible high-strength solid electrolyte described in the second aspect in the field of flexible batteries and / or solid-state batteries.

[0047] The present invention is described in detail below by way of examples. Unless otherwise specified, the raw materials used are all common commercially available products.

[0048] Polyethylene oxide: It is in powder form and has a number average molecular weight of 600,000.

[0049] Example 1

[0050] This example is used to illustrate the method for preparing a flexible high-strength solid electrolyte provided by the present invention, which is performed according to the following steps:

[0051] (1) grinding NiCl2 and octadecylamine in a ball mill at a weight ratio of 1:2 to obtain 15 g of raw material powder with an average volume diameter of 2.36 mm, wherein the content of NiCl2 is 5 g and the content of octadecylamine is 10 g;

[0052] Then, the raw material powder is added to dimethylformamide for heat treatment at 90° C. for 20 hours, and then sintered at 230° C. in a nitrogen atmosphere for 20 hours to obtain a flexible material; wherein the weight ratio of the dimethylformamide to the raw material powder is 4:1;

[0053] (2) dissolving polyethylene oxide (600 mg) and deionized water in a weight ratio of 0.05:1 for 100 minutes using magnetic stirring at a speed of 500 rpm; then adding the lithium bis(trifluoromethylsulfonyl)imide and dissolving it for a second time for 120 minutes using magnetic stirring at a speed of 600 rpm to obtain the solution A; wherein the weight ratio of polyethylene oxide to lithium bis(trifluoromethylsulfonyl)imide is 10:1;

[0054] (3) The flexible material is dispersed in water to obtain a dispersion of the flexible material with a concentration of 60 wt%, and then 60 mg of the dispersion of the flexible material is added to the solution A to obtain solution B. The solution B is then stirred for 1 hour and ultrasonicated for 1 hour, and the stirring and ultrasonication are repeated once. Finally, the solution is dried to a moisture content of 0.0001 wt% to obtain the flexible high-strength solid electrolyte, which is named P1.

[0055] Figure 1 The SEM image of P1 is shown, from which it can be clearly seen that the surface of the flexible high-strength solid electrolyte prepared by the present invention is very flat.

[0056] Example 2

[0057] This example is used to illustrate the method for preparing a flexible high-strength solid electrolyte provided by the present invention, which is performed according to the following steps:

[0058] (1) grinding NiCl2 and octadecylamine in a ball mill at a weight ratio of 1:2 to obtain 15 g of raw material powder with an average volume diameter of 1.7 mm, wherein the content of NiCl2 is 5 g and the content of octadecylamine is 10 g;

[0059] Then, the raw material powder is added to dimethylformamide for heat treatment at 80° C. for 20 hours, and then sintered at 230° C. in a nitrogen atmosphere for 20 hours to obtain a flexible material; wherein the weight ratio of the dimethylformamide to the raw material powder is 3.5:1;

[0060] (2) using magnetic stirring at a speed of 500 rpm, dissolving polyethylene oxide (600 mg) and deionized water in a weight ratio of 0.05:1 for a first time for 60 minutes; then adding the lithium bis(trifluoromethylsulfonyl)imide, and using magnetic stirring at a speed of 600 rpm for a second time for 120 minutes to obtain the solution A; wherein the weight ratio of polyethylene oxide to lithium bis(trifluoromethylsulfonyl)imide is 10:1;

[0061] (3) The flexible material is dispersed in water to obtain a dispersion of the flexible material with a concentration of 50 wt%, and then 70 mg of the dispersion of the flexible material is added to the solution A to obtain solution B. The solution B is then stirred for 0.5 h and ultrasonicated for 1 h, and the stirring and ultrasonication are repeated once. Finally, the solution is dried to a moisture content of 0.001 wt% to obtain the flexible high-strength solid electrolyte, which is named P2.

[0062] Example 3

[0063] This example is carried out using a method similar to that of Example 1, except that in step (1), NiCl2 and octadecylamine are ground using a ball mill to obtain a raw material powder with an average volume diameter of 3 mm;

[0064] Finally, a flexible and high-strength solid electrolyte was obtained, named P3.

[0065] Example 4

[0066] This example is carried out in a similar manner to Example 1, except that in step (3), the amount of the flexible material used is 20 mg;

[0067] Finally, a flexible and high-strength solid electrolyte was obtained, named P4.

[0068] Comparative Example 1

[0069] This comparative example was carried out using a method similar to that of Example 1, except that in step (1), the sintering temperature was 850°C;

[0070] Finally, a solid electrolyte was obtained and named DP1.

[0071] Comparative Example 2

[0072] This comparative example was carried out using a method similar to that of Example 1, except that in step (1), the sintering temperature was 200°C;

[0073] The final result was a solid electrolyte named DP2.

[0074] Comparative Example 3

[0075] This comparative example was carried out in a manner similar to that of Example 1, except that in step (1), the amount of NiCl2 used was 15 g and the amount of octadecylamine used was 12 g;

[0076] The final result was a solid electrolyte named DP3.

[0077] Comparative Example 4

[0078] This comparative example was carried out in a similar manner to Example 1, except that in step (1), an equal mass of polyacrylonitrile (15 g) was used instead of the raw material powder;

[0079] The final result was a solid electrolyte named DP4.

[0080] Test Example 1

[0081] The flexible high-strength solid electrolyte and solid electrolyte prepared in the above examples were tested for tensile stress and ionic conductivity. The results are shown in Table 1.

[0082] in, Figure 2 The figure shows the actual stretching of P1; it can be seen from the figure that P1 has super strong strain resistance to battery short circuit;

[0083] Figure 3 The tensile stress intensity and strain diagram of P1 is shown. It can be seen from the figure that P1 can be stretched to 12 times its length.

[0084] Figure 4 The ionic conductivity of P1 is shown in the figure. It can be seen that the ionic conductivity of P1 can be as high as 2.12x10 -4 S / cm -1 .

[0085] Table 1

[0086] Performance indicators P1 P2 P3 P4 Tensile stress (Mpa) 5.25 3.89 2.67 3.42 Tensile strain (%) 1281 981 783 897 <![CDATA[Ionic conductivity (S / cm -1 )]]> <![CDATA[2.12x10 -4 ]]> <![CDATA[0.4x10 -4 ]]> <![CDATA[9.8x10 -5 ]]> <![CDATA[0.32x10 -4 ]]>

[0087] Table 1 continued

[0088] Performance indicators DP1 DP2 DP3 DP4 Tensile stress (Mpa) 1.02 0.78 0.98 0.85 Tensile strain (%) 236 185 169 196 <![CDATA[Ionic conductivity (S / cm -1 )]]> <![CDATA[7.89x10 -5 ]]> <![CDATA[8.12x10 -5 ]]> <![CDATA[8.98x10 -5 ]]> <![CDATA[7.89x10 -5 ]]>

[0089] The above results demonstrate that the method for preparing a flexible, high-strength solid-state electrolyte provided by the present invention, through the rational selection of raw materials, optimized material formulation, and precise control of the preparation process, successfully produces a flexible, high-strength solid-state electrolyte with high ionic conductivity and excellent mechanical strength. This solid-state electrolyte offers advantages such as a simple preparation process, low cost, and stable performance. It effectively addresses the safety and stability issues of traditional liquid electrolytes, providing a new solution for the development of battery technology.

[0090] In addition, applying this solid-state electrolyte to flexible batteries can produce battery components with high energy density, long cycle life and good flexibility, which are suitable for various mobile electronic devices and portable power supplies; at the same time, applying it to solid-state batteries can produce safer, more stable and higher energy density batteries, thereby promoting the development of electric vehicles, energy storage systems and other fields.

[0091] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a flexible high-strength solid electrolyte, characterized in that: The method includes: (1) heat-treating the raw material powder in the presence of dimethylformamide and then sintering it at 220-250° C. to obtain a flexible material; (2) dissolving polyethylene oxide and lithium bis(trifluoromethylsulfonyl)imide in the presence of water to obtain solution A; (3) contacting the dispersion of the flexible material with the solution A to obtain a flexible high-strength solid electrolyte; The raw material powder is composed of NiCl2 and octadecylamine, and the weight ratio of the NiCl2 to the octadecylamine in the raw material powder is 1:2-3; In step (1), the average volume diameter of the raw material powder is 1.5-2.5 mm; In step (3), the weight ratio of the polyethylene oxide in the solution A to the flexible material is 10:1-2.

2. The method according to claim 1, wherein In step (1), the weight ratio of the dimethylformamide to the raw material powder is 3-4:

1.

3. The method according to claim 1 or 2, wherein: In step (1), the heat treatment conditions at least meet the following requirements: temperature of 60-90° C. and time of 18-24 h.

4. The method according to claim 1 or 2, wherein: In step (1), the sintering time is 18-24 hours.

5. The method according to claim 1 or 2, wherein: In step (3), the dispersion of the flexible material is a product obtained by dispersing the flexible material in water, and in the dispersion of the flexible material, the concentration of the flexible material is 50-60 wt %.

6. The method according to claim 1 or 2, wherein: In step (3), the contact reaction operation includes: adding the dispersion of the flexible material to the solution A to obtain a solution B, and then stirring, ultrasonicating, and drying the solution B in sequence to obtain the flexible high-strength solid electrolyte; The operation of the contact reaction includes: stirring the solution B for 0.5-2 hours, ultrasonicating for 0.5-2 hours, repeating the stirring and ultrasonicating at least once, and then drying until the moisture content is no more than 0.01wt% to obtain the flexible high-strength solid electrolyte.

7. A flexible and high-strength solid electrolyte prepared by the method according to any one of claims 1 to 6.

8. Use of the flexible high-strength solid electrolyte according to claim 7 in the field of flexible batteries and / or solid-state batteries.

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