Polymer Solid Electrolyte Incorporated with Phase Change Temperature-Regulating Material, Its Preparation and Application

Abstract

The present invention relates to a polymer solid electrolyte incorporated with a phase change temperature regulating material, its preparation and application. The solid electrolyte aims to solve the problem of battery thermal runaway. The electrolyte is based on polyethylene oxide (PEO) and is prepared by controlling the molar ratios of PEO, lithium salt and the phase change temperature regulating material. The electrolyte presents a solid state at room temperature, but can absorb heat through phase change at high temperatures, thereby realizing the regulation and control of the battery temperature. The electrolyte has good conductivity and stability, and can effectively absorb the heat generated by the battery at high temperatures, thus avoiding the safety problems caused by battery thermal runaway. The phase change temperature regulating polymer solid electrolyte has a wide range of applications and can be applied to various types of batteries such as lithium-ion batteries, sodium-ion batteries, lead-acid batteries, and supercapacitors. The electrolyte is innovative and practical, providing a new solution for improving battery safety.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry technology, and particularly relates to a polymer solid electrolyte incorporated with a phase change temperature regulating material and its preparation and application. Background Art

[0002] With the continuous increase in the demand for portable electronic products in modern society, the development of battery technology has become increasingly important. Lithium-ion batteries have become one of the most popular batteries due to their high energy density, long life, and good cycling performance. However, the liquid electrolyte in lithium-ion batteries may cause thermal runaway at high temperatures and is prone to leakage, which has a significant impact on the performance and safety of the batteries. Therefore, the research and development of new solid electrolytes to replace liquid electrolytes have become an important research direction in the field of lithium-ion batteries.

[0003] PEO polymer solid electrolyte is an electrolyte material used in high-energy density batteries such as lithium-ion batteries. Compared with liquid electrolytes, solid electrolytes have higher ionic conductivity, better mechanical strength, and higher thermal stability, and are therefore considered an important material that can improve the safety of batteries. Solid electrolytes can avoid the problems of leakage and volatilization existing in liquid electrolytes, thereby improving the safety of the batteries. At the same time, PEO polymer solid electrolyte also has a high lithium-ion conductivity and chemical stability, which can effectively inhibit the growth of lithium dendrites and avoid problems such as internal short circuit and thermal runaway of the batteries. In addition, PEO polymer solid electrolyte also has good processability and can be formed by methods such as injection molding, which can effectively improve the production efficiency and consistency of the batteries, thereby improving the performance and safety of the batteries.

[0004] However, on the other hand, the current PEO solid has poor thermal stability, and PEO is easy to decompose, especially at high temperatures. When the battery gets out of control, the temperature may exceed the decomposition temperature of PEO, resulting in the thermal decomposition of PEO and the release of flammable gases, thereby exacerbating the degree of battery out-of-control. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects existing in the above-mentioned prior art and provide a polymer solid electrolyte incorporated with a phase change temperature regulating material and its preparation and application. By adding a temperature-adjustable phase change temperature regulating material (PCM) to PEO, a solid electrolyte with low cost, simple process, mild conditions, and very good stability is obtained.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A preparation method of a polymer solid electrolyte incorporated with a phase change temperature regulating material, the specific steps are as follows:

[0008] S1. Prepare the phase change temperature regulating material;

[0009] S2. Prepare the PEO polymer solution;

[0010] S3. Add the phase change temperature regulating material obtained in step S1 into the PEO polymer solution obtained in step S2 and ultrasonicate to obtain the mixed solution A;

[0011] S4. Dry the mixed solution A obtained in step S3 to obtain the polymer solid electrolyte doped with the phase change temperature regulating material.

[0012] Further, in step S1, FeCl2·4H2O and C n H 2n+1 NH2 are mixed and ground, then added into an organic solvent to form a sol, and after heating, a phase change precursor material is obtained. The phase change precursor material is sintered to obtain the phase change temperature regulating material.

[0013] Still further, FeCl2·4H2O and C n H 2n+1 NH2 are put into a ball mill or a high-energy grinder for mixing and grinding, then the mixed and ground raw materials are added into an organic solvent to form a sol, and then the phase change precursor material is obtained through heating evaporation and gelation. Finally, the phase change precursor material is put into a high-temperature furnace for sintering treatment to make it a dense phase change temperature regulating material.

[0014] Still further, the molar ratio of FeCl2·4H2O:C n H 2n+1 NH2:organic solvent is 1.5 - 2.5:0.5 - 1.5:7, preferably 2:1:7.

[0015] Still further, n in C n H 2n+1 NH2 is 1 - 3.

[0016] Still further, the grinding time is 5 - 6 hours.

[0017] Still further, the organic solvent is N,N-dimethylformamide (DMF).

[0018] Still further, the heating evaporation time is 12 - 24 hours.

[0019] Still further, the sintering temperature is 200 - 250 °C, the sintering atmosphere is nitrogen, and the sintering time is 18 - 24 hours.

[0020] Further, in step S2, poly(ethylene oxide) (PEO) is stirred evenly in deionized water, then a lithium salt is added and fully dissolved to obtain the PEO polymer solution.

[0021] Furthermore, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSi), and polyethylene oxide (PEO) is the substrate of the polymer solid electrolyte, mainly acting as a substrate. After adding the lithium salt, it can promote the decomposition of the lithium salt, thereby enabling the transport of lithium ions.

[0022] Furthermore, the polyethylene oxide is in powder form.

[0023] Furthermore, the number-average molecular weight of the polyethylene oxide is 600,000 - 1,000,000.

[0024] Furthermore, the concentration of the polyethylene oxide in the PEO polymer solution is 85% - 95%, preferably 90%.

[0025] Furthermore, the mass ratio of the lithium salt to the polyethylene oxide is 1 - 1.5:10.

[0026] Furthermore, the stirring time is 12 - 24 hours.

[0027] Further, in step S3, the mass ratio of the phase change temperature regulating material to the polyethylene oxide in the PEO polymer solution is 1 - 2:10.

[0028] Further, in step S3, the phase change temperature regulating material obtained in step S1 is added to the PEO polymer solution obtained in step S2, and magnetically stirred and ultrasonicated to obtain a mixed solution A.

[0029] Furthermore, the magnetic stirring time is 12 - 24h.

[0030] Furthermore, the ultrasonic time is 10 - 15h.

[0031] Further, in step S4, the mixed solution A obtained in step S3 is dropped onto a mold and dried to obtain a polymer solid electrolyte doped with a phase change temperature regulating material.

[0032] Furthermore, the mold is a grid mold made of polytetrafluoroethylene.

[0033] Furthermore, the drying time is 12 - 24 hours.

[0034] The present invention also provides a polymer solid electrolyte doped with a phase change temperature regulating material, which is prepared by using the preparation method of the polymer solid electrolyte doped with the phase change temperature regulating material described above.

[0035] Further, the polymer solid electrolyte doped with the phase change temperature regulating material as a whole presents a uniformly dispersed, flat and full white film.

[0036] In addition, the present invention also provides a lithium-ion battery, including a polymer solid electrolyte doped with the above phase change temperature regulating material.

[0037] The principle of the present invention is as follows:

[0038] The phase change temperature regulating material (PCM) can control the temperature in the battery. The performance and lifespan of the battery are usually affected by temperature. Excessive or too low temperature will lead to a decline in battery performance or damage. The PCM can act as a temperature regulator, controlling the battery temperature by absorbing or releasing heat and keeping the battery within the optimal operating temperature range.

[0039] During the use of the battery, a large amount of heat is generated. If this heat is not processed in time, it may cause the internal temperature of the battery to be too high, thus affecting the performance and lifespan of the battery. The PCM can be used as a thermal management material, absorbing the heat generated inside the battery and releasing it to the external environment, thereby maintaining the temperature balance inside the battery.

[0040] By adding the phase change temperature regulating material (PCM) to the PEO polymer solid state and obtaining a composite polymer solid electrolyte material with uniform dispersion, the present invention can improve the originally insufficient cycle stability and increase its ionic conductivity, making it have better thermal stability.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention mixes the phase change temperature regulating material (PCM) and PEO and then dries them on a mold, finally obtaining a PEO polymer solid electrolyte with uniformly dispersed phase change temperature regulating material filler, and the method is simple.

[0043] 2. The present invention uses the phase change temperature regulating material (PCM) as a filler, and the raw materials have designability and wide applications.

[0044] 3. The polymer solid electrolyte doped with the phase change temperature regulating material prepared by the method of the present invention, with the phase change temperature regulating material added as a filler, can significantly improve its thermal stability, increase the ionic conductivity and mechanical strength of the solid electrolyte.

[0045] 4. The phase change temperature regulating material can be applied in the PEO polymer solid electrolyte to improve the thermal stability and cycle lifespan of the battery. Introducing PCM into the PEO polymer solid electrolyte can utilize the phase change characteristics of PCM to absorb or release heat during the battery process, thereby avoiding safety problems caused by battery thermal runaway, controlling the battery temperature, improving the thermal stability of the battery. At the same time, since the heat absorption and heat release process of PCM can improve the internal heat flow distribution of the battery, it further improves the cycle lifespan of the battery.

[0046] 5. The polymer solid electrolyte incorporated into the phase change temperature regulating material obtained in the present invention has a wide range of applications and can be applied to various types of batteries such as lithium-ion batteries, sodium-ion batteries, lead-acid batteries, and supercapacitors. This electrolyte is innovative and practical, providing a new solution for improving battery safety. Description of the Drawings

[0047] Figure 1 SEM image of the surface of the pure PEO polymer solid electrolyte obtained in Comparative Example 1;

[0048] Figure 2 Cross-sectional SEM image of the pure PEO polymer solid electrolyte in Example 1;

[0049] Figure 3 SEM image of the surface of the polymer solid electrolyte incorporated with the phase change temperature regulating material obtained in Example 1;

[0050] Figure 4 Cross-sectional SEM image of the polymer solid electrolyte incorporated with the phase change temperature regulating material obtained in Example 1;

[0051] Figure 5 High-temperature thermal imaging comparison diagram of the pure PEO polymer solid electrolyte obtained in Comparative Example 1 and the polymer solid electrolyte incorporated with the phase change temperature regulating material obtained in Example 1;

[0052] Figure 6 Ionic conductivity comparison diagram of the pure PEO polymer solid electrolyte obtained in Comparative Example 1 and the polymer solid electrolyte incorporated with the phase change temperature regulating material obtained in Example 1. Detailed Description of the Embodiments

[0053] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] This example provides a preparation method for a polymer solid electrolyte incorporated with a phase change temperature regulating material, and the specific steps are as follows:

[0056] First step, phase change temperature regulating material:

[0057] (1) Put the raw materials FeCl2·4H2O and C2H5NH2 into a ball mill for mixing and grinding, and then add the mixed and ground raw materials into N,N-dimethylformamide to make a sol, where the molar ratio of FeCl2·4H2O:C2H5NH2:N,N-dimethylformamide is 2:1:7;

[0058] (2) Gel the sol obtained in step (1) by heating and evaporating for 12 - 24 hours to obtain a phase change precursor material;

[0059] (3) Finally, put the phase change precursor material obtained in step (2) into a high-temperature furnace and sinter it at 200 - 250 °C for 24 hours to make it a dense phase change temperature-regulating material.

[0060] Second step: Prepare the PEO polymer solution:

[0061] Mix 600 mg of polyethylene oxide (PEO) in deionized water and stir for 12 h, then add 60 mg of LiTFSi, and ultrasonically dissolve it to obtain a PEO polymer solution. Among them, the concentration of polyethylene oxide in the PEO polymer solution is 90%.

[0062] Third step: Prepare the polymer solid electrolyte doped with the phase change temperature-regulating material:

[0063] Add 60 mg of the phase change temperature-regulating material obtained in the first step to the PEO polymer solution obtained in the second step, stir magnetically for 12 h, and ultrasonically for 10 h to obtain a mixed solution A. Drop the mixed solution A onto a square mold made of polytetrafluoroethylene and dry it for 24 h to obtain the polymer solid electrolyte doped with the phase change temperature-regulating material. The morphology diagram is as Figure 1 shown;

[0064] Example 2

[0065] This example is basically the same as Example 1, except that in this example, in the third step, the addition amount of the phase change temperature-regulating material is 50 mg.

[0066] Example 3

[0067] This example is basically the same as Example 1, except that in this example, in the third step, the addition amount of the phase change temperature-regulating material is 70 mg.

[0068] Comparative Example 1

[0069] This comparative example uses a pure PEO polymer solid electrolyte.

[0070] Figure 1 is the SEM image of the surface of the pure PEO polymer solid electrolyte obtained in Comparative Example 1. It can be clearly seen from it that the surface is uneven and there are many holes; Figure 2 is the cross-sectional SEM image of the pure PEO polymer solid electrolyte in Example 1. It can be seen from it that the cross-section is uneven; Figure 3 is the SEM image of the surface of the polymer solid electrolyte doped with the phase change temperature-regulating material obtained in Example 1. It can be seen from it that the surface is very flat and uniform; Figure 4 is the cross-sectional SEM image of the polymer solid electrolyte doped with the phase change temperature-regulating material obtained in Example 1. It can be seen from it that the cross-section is very full.

[0071] Figure 5 It is a high-temperature thermal imaging comparison diagram of the pure PEO polymer solid electrolyte obtained in Comparative Example 1 and the polymer solid electrolyte incorporated with the phase change temperature-regulating material obtained in Example 1. It can be seen that the thermal performance has been significantly improved after adding the phase change temperature-regulating material;

[0072] Figure 6 It is a comparison diagram of the ionic conductivity of the pure PEO polymer solid electrolyte obtained in Comparative Example 1 and the polymer solid electrolyte incorporated with the phase change temperature-regulating material obtained in Example 1. It can be seen that the ionic conductivity has been greatly improved after adding the phase change temperature-regulating material, up to 2.56x10 -4 S / cm -1 , and the phase change temperature-regulating material can be applied in the PEO polymer solid electrolyte to improve the thermal stability and cycle life of the battery, absorb or release heat during the battery process, thereby avoiding safety problems caused by battery thermal runaway.

[0073] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A preparation method of a polymer solid electrolyte doped with a phase change temperature regulating material, characterized in that The specific steps are as follows: S1. Prepare a phase change temperature regulating material; S2. Prepare a PEO polymer solution; S3. Add the phase change temperature regulating material obtained in step S1 into the PEO polymer solution obtained in step S2 and perform ultrasonic treatment to obtain a mixed solution A; S4. Dry the mixed solution A obtained in step S3 to obtain a polymer solid electrolyte doped with the phase change temperature regulating material; In step S1, FeCl2·4H2O and C n H 2n+1 NH2 are put into a ball mill or a high-energy grinder for mixing and grinding, and then the mixed and ground raw materials are added into an organic solvent to form a sol. Then, through heating evaporation and gelation, a phase change precursor material is obtained. Finally, the phase change precursor material is put into a high-temperature furnace for sintering treatment to make it a dense phase change temperature-regulating material; FeCl2·4H2O:C n H 2n+1 The molar ratio of NH2:organic solvent is 1.5~2.5:0.5~1.5:7 C n H 2n+1 in C n H 2n+1 NH2, n is from 1 to 3, The grinding time is 5 - 6 hours, The organic solvent is N,N-dimethylformamide, The heating and evaporation time is 12 - 24 hours, The sintering temperature is 200 - 250 °C, the sintering atmosphere is nitrogen, and the sintering time is 18 - 24 hours; In step S2, polyethylene oxide is stirred evenly in deionized water, then a lithium salt is added, and after being fully dissolved, a PEO polymer solution is obtained, The lithium salt is lithium bis(trifluoromethanesulfonyl)imide, and the polyethylene oxide is in powder form, The number average molecular weight of the polyethylene oxide is 600,000 - 1,000,000, The concentration of the polyethylene oxide in the PEO polymer solution is 85% - 95%, The mass ratio of the lithium salt to the polyethylene oxide is 1 - 1.5:10, The stirring time is 12 - 24 hours.

2. The preparation method of the polymer solid electrolyte doped with the phase change temperature regulating material according to claim 1, characterized in that, In step S3, the mass ratio of the phase change temperature regulating material to the polyethylene oxide in the PEO polymer solution is 1 - 2:10; Magnetic stirring treatment is carried out before the ultrasonic process, and the magnetic stirring time is 12 - 24 h, The ultrasonic time is 10 - 15 h.

3. The preparation method of the polymer solid electrolyte doped with the phase change temperature regulating material according to claim 1, characterized in that, In step S4, the mixed solution A obtained in step S3 is dropped on a square mold made of polytetrafluoroethylene for drying, The drying time is 12 - 24 hours.

4. A polymer solid electrolyte incorporated with a phase change temperature regulating material, characterized in that, It is prepared by using the preparation method of the polymer solid electrolyte doped with the phase change temperature regulating material as described in any one of claims 1 - 3.

5. The polymer solid electrolyte incorporated with the phase change temperature regulating material according to claim 4, characterized in that, The polymer solid electrolyte doped with the phase change temperature regulating material as a whole presents a uniformly dispersed, flat and plump white film.

6. A lithium-ion battery, characterized in that, It includes the polymer solid electrolyte doped with the phase change temperature regulating material as described in claim 4 or claim 5.

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