A self-repairing electrolyte with multiple disulfide dynamic bonds and its preparation method

Abstract

The present invention discloses a self-repairing electrolyte with multiple disulfide dynamic bonds and a preparation method thereof, which comprises the following steps: (1) dissolving a monomer A containing a disulfide bond in chloroform, then dropwise adding a chlorine-containing monomer B to react, washing and drying, then adding acetonitrile to form a solution with a concentration of 30wt%, finally adding vinyl imidazole to react for 3-5d, precipitating with a precipitant to obtain a cross-linking agent; (2) melting thioctic acid at a temperature of 90-120°C, then adding a lithium salt, an ionic liquid and the cross-linking agent obtained in step (1) to react, and naturally cooling to obtain a self-repairing electrolyte with multiple disulfide dynamic bonds. The present invention also includes a self-repairing electrolyte with multiple disulfide dynamic bonds obtained by the above method. The present invention effectively solves the problems of cracks, delamination and even fracture caused by repeated bending of flexible batteries in the prior art, and also has good performance in heat resistance.

Description

Technical Field

[0001] The present invention relates to the field of battery electrochemical technology, and in particular to a self-repairing electrolyte with multiple disulfide dynamic bonds and a preparation method thereof. Background Art

[0002] Flexible lithium-ion solid-state electrolytes currently face defects such as cracks, delamination, and even fractures caused by mechanical fatigue. If these defects are not promptly controlled, they can lead to serious safety hazards such as short circuits, thermal runaway, and even explosions. Self-healing materials, a class of intelligent materials developed in the 20th century, are capable of repairing mechanical damage and hold great potential for extending their service life and enhancing their fatigue resistance. Self-healing mechanisms are generally categorized into two types: externally assisted self-healing and intrinsic self-healing. Externally assisted self-healing primarily utilizes healing agents released upon rupture from disposable microcapsules embedded in a matrix, such as reusable hollow tubes, to physically or chemically heal the material. Externally assisted self-healing materials, in which healing agents are embedded in microcapsules, arrays of hollow tubes, and 3D interconnecting tubes, have demonstrated excellent single- and multiple-time healing performance. Intrinsically assisted self-healing materials utilize inherently reversible chemical bonds within the material to enable self-healing of damaged areas, eliminating the need for external healing agents.

[0003] This shows that intrinsic self-repair mechanisms are widely studied due to their fast response speed, reusability, and simple process. Reversible chemical bonds generally used for intrinsic self-repair are divided into two categories: reversible covalent bonds (Diels-Alder (DA) reaction, disulfide bonds, acylhydrazone bonds, borate bonds, etc.) and reversible non-covalent bonds (hydrogen bonds, ionic bonds, hydrophobic interactions, etc.). As a type of reversible covalent bond, disulfide bonds have the characteristics of mild reversible conditions, good mechanical properties, and fast response. In particular, the introduction of multiple disulfide bonds has good synergistic effects, can achieve the ability of rapid self-repair at room temperature, and has excellent application prospects. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a self-healing electrolyte with multiple disulfide dynamic bonds and a preparation method thereof. A cross-linking agent is prepared by using a disulfide bond-containing monomer A, a chlorine-containing monomer B and vinyl imidazole, and then a self-healing electrolyte with multiple disulfide dynamic bonds is prepared with thioctic acid, lithium salt and ionic liquid, which extends the service life of the electrolyte and effectively solves the problems of cracks, delamination and even breakage caused by repeated bending of flexible batteries in the prior art, and also has good performance in heat resistance.

[0005] The present invention solves the above technical problems with the following technical solution: a method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds is provided, comprising the following steps:

[0006] (1) Dissolving a disulfide-containing monomer A in chloroform, then dropwise adding a chlorine-containing monomer B for reaction, washing and drying, then adding acetonitrile to prepare a 30 wt% solution, and finally adding vinyl imidazole for reaction for 3-5 days, followed by precipitation with a precipitant to obtain a crosslinker;

[0007] (2) melting lipoic acid at 90-120° C., then adding lithium salt, ionic liquid and the cross-linking agent obtained in step (1) to react for 1-3 minutes, and naturally cooling to obtain a self-healing electrolyte with multiple disulfide dynamic bonds.

[0008] Furthermore, in step (1), the disulfide bond-containing monomer A is bishydroxyethyl disulfide or bisaminoethyl disulfide; and the chlorine-containing monomer B is 2-chloroethyl isocyanate or 3-chloropropyl isocyanate.

[0009] Furthermore, in step (1), the reaction is carried out at a temperature of 25-60°C.

[0010] Furthermore, when the monomer A containing a disulfide bond is bishydroxyethyl disulfide, the reaction is carried out at a temperature of 60°C; when the monomer A containing a disulfide bond is bisaminoethyl disulfide, the reaction is carried out at a temperature of 60°C.

[0011] Further, in step (1), vinyl imidazole is 1-C (n) Alkenyl imidazole, n is 2-4.

[0012] Furthermore, in step (1), the precipitant is ether or ethyl acetate.

[0013] Furthermore, in step (2), the lithium salt is LiTFSI, LiClO4, LiPF6 or LiBF4.

[0014] Furthermore, in step (2), the ionic liquid is 1-ethyl-3-methylimidazole or 1-propyl-3-methylimidazole.

[0015] Furthermore, in step (2), the added amounts of lithium salt, ionic liquid and cross-linking agent are all 10-30 wt%.

[0016] The self-repairing electrolyte with multiple disulfide dynamic bonds prepared by the preparation method of the self-repairing electrolyte with multiple disulfide dynamic bonds.

[0017] The present invention has the following beneficial effects:

[0018] 1. The present invention prepares a cross-linking agent by using a monomer A containing a disulfide bond, a chlorine-containing monomer B and vinyl imidazole, and then prepares a self-healing electrolyte with multiple disulfide dynamic bonds with lipoic acid, lithium salt and ionic liquid, thereby extending the service life of the electrolyte and effectively solving the problems of cracks, delamination and even breakage caused by repeated bending of flexible batteries in the prior art. It also has good heat resistance.

[0019] 2. The present invention first prepares a cross-linking agent having a disulfide bond and a diene bond; on the one hand, the diene bond can undergo an ene-sulfide click reaction with lipoic acid at high temperature to inhibit the depolymerization reaction of lipoic acid to form a polymer; on the other hand, the disulfide bond possessed by the cross-linking agent itself and the disulfide bond formed after the ring opening of lipoic acid play a synergistic role to achieve room temperature self-repair; in addition, the imidazole ring in the cross-linking agent has better compatibility with imidazolium ionic liquids, which contributes to high ionic conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the NMR spectrum of the cross-linking agent obtained in Example 1;

[0021] Figure 2 This is the Raman spectrum of the self-healing electrolyte with multiple disulfide dynamic bonds obtained in Example 1;

[0022] Figure 3 Demonstration of electrochemical self-repair of the self-repairing electrolyte with multiple disulfide dynamic bonds obtained in Example 1;

[0023] Figure 4 This is the microscopic morphology evolution of the self-healing electrolyte with multiple disulfide dynamic bonds obtained in Example 1 before and after self-healing. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below. The examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In the examples, where specific conditions are not specified, conventional conditions or manufacturer-recommended conditions were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0025] Example 1

[0026] A self-healing electrolyte having multiple disulfide dynamic bonds, the preparation method of which comprises the following steps:

[0027] (1) Dissolve bis(hydroxyethyl) disulfide in chloroform, then add 2-chloroethyl isocyanate dropwise, react at 60°C, wash and dry, then add acetonitrile to prepare a solution with a concentration of 30 wt%, and finally add 1-chloroethyl isocyanate. (2) The vinyl imidazole reacts for 4 days and is precipitated with ether to obtain the cross-linking agent;

[0028] (2) Melting lipoic acid at 110° C., then adding LiTFSI, 1-ethyl 3-methylimidazole and the cross-linking agent obtained in step (1) to react, with the addition amount of each being 20 wt %, and naturally cooling to obtain a self-healing electrolyte with multiple disulfide dynamic bonds.

[0029] Example 2

[0030] A self-healing electrolyte having multiple disulfide dynamic bonds, the preparation method of which comprises the following steps:

[0031] (1) Dissolve bis(hydroxyethyl) disulfide in chloroform, then add 2-chloroethyl isocyanate dropwise, react at 60°C, wash and dry, then add acetonitrile to prepare a solution with a concentration of 30 wt%, and finally add 1-chloroethyl isocyanate. (2) The vinyl imidazole reacts for 3 days and is precipitated with ether to obtain the cross-linking agent;

[0032] (2) Melting lipoic acid at 90° C., then adding LiClO 4 , 1-propyl-3-methylimidazole and the cross-linking agent obtained in step (1) to react, with the addition amount of each being 10 wt %, and naturally cooling to obtain a self-healing electrolyte with multiple disulfide dynamic bonds.

[0033] Example 3

[0034] A self-healing electrolyte having multiple disulfide dynamic bonds, the preparation method of which comprises the following steps:

[0035] (1) Dissolve bisaminoethyl disulfide in chloroform, then add 3-chloropropyl isocyanate dropwise, react at 25°C, wash and dry, then add acetonitrile to prepare a solution with a concentration of 30 wt%, and finally add 1-C (3) The vinyl imidazole was reacted for 4 days and precipitated with ethyl acetate to obtain the cross-linking agent;

[0036] (2) Melting lipoic acid at 100° C., then adding LiPF6, 1-propyl-3-methylimidazole and the cross-linking agent obtained in step (1) to react, with the addition amount of each being 20 wt %. The mixture is cooled naturally to obtain a self-healing electrolyte with multiple disulfide dynamic bonds.

[0037] Example 4

[0038] A self-healing electrolyte having multiple disulfide dynamic bonds, the preparation method of which comprises the following steps:

[0039] (1) Dissolve bisaminoethyl disulfide in chloroform, then add 3-chloropropyl isocyanate dropwise, react at 25°C, wash and dry, then add acetonitrile to prepare a solution with a concentration of 30 wt%, and finally add 1-C (4) The vinyl imidazole was reacted for 5 days and precipitated with ethyl acetate to obtain the cross-linking agent;

[0040] (2) Melting lipoic acid at 120° C., then adding LiBF 4 , 1-propyl-3-methylimidazole and the cross-linking agent obtained in step (1) to react, with the addition amount of each being 30 wt %, and naturally cooling to obtain a self-healing electrolyte with multiple disulfide dynamic bonds.

[0041] Experimental example

[0042] The nuclear magnetic spectrum of the cross-linking agent obtained in Example 1 and the Raman spectra of the cross-linking agent and the self-healing electrolyte with multiple disulfide dynamic bonds were obtained, and the results were as follows: Figure 1-2 shown.

[0043] Depend on Figure 1 It can be seen that the successful preparation of the cross-linking agent can be determined from the characteristic peaks near 9.5, 8.0, 7.5, 6.5 and 3.5 ppm, which are attributed to the proton peaks on the imidazole ring, vinyl and methylene, respectively.

[0044] Depend on Figure 2 It can be seen that the characteristic peaks observed near 526 and 625 cm-1 belong to disulfide bonds, indicating that the target product of the present invention, a self-healing electrolyte with multiple disulfide dynamic bonds, has been successfully prepared.

[0045] The electrochemical self-repairing demonstration of the self-repairing electrolyte with multiple disulfide dynamic bonds obtained in Example 1 was carried out. Figure 3 As shown; and observe the evolution of the microscopic morphology before and after self-repair, as shown Figure 4 shown.

[0046] Depend on Figure 3 It can be seen that after the electrolyte is assembled into a device, it can start the electronic timer. Then, when the device is cut off, the contact self-repair can be performed and the electronic timer can be powered again. This fully demonstrates that the multiple disulfide bonds give the electrolyte a self-repair function.

[0047] Depend on Figure 4 It can be seen that the cracks scratched with a knife appear as wider marks under a microscope. After self-repair, the cracks are almost completely repaired, leaving only traces of fine lines.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds, characterized in that: The following steps are involved: (1) Dissolve the disulfide-containing monomer A in chloroform, then dropwise add the chlorine-containing monomer B to react, wash and dry, then add acetonitrile to prepare a solution with a concentration of 30 wt%, finally add vinyl imidazole and react for 3-5 days, and precipitate with a precipitant to obtain a crosslinker; (2) melting lipoic acid at 90-120° C., then adding lithium salt, ionic liquid and the cross-linking agent obtained in step (1) to react for 1-3 minutes, and naturally cooling to obtain a self-healing electrolyte with multiple disulfide dynamic bonds; Wherein, in step (1), the disulfide bond-containing monomer A is bishydroxyethyl disulfide or bisaminoethyl disulfide; and the chlorine-containing monomer B is 2-chloroethyl isocyanate or 3-chloropropyl isocyanate.

2. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: In step (1), the reaction is carried out at a temperature of 25-60°C.

3. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: When the monomer A containing a disulfide bond is bishydroxyethyl disulfide, the reaction is carried out at a temperature of 60°C; when the monomer A containing a disulfide bond is bisaminoethyl disulfide, the reaction is carried out at a temperature of 25°C.

4. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: In step (1), the precipitant is ether or ethyl acetate.

5. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: In step (2), the lithium salt is LiTFSI, LiClO4, LiPF6 or LiBF4.

6. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: In step (2), the ionic liquid is 1-ethyl-3-methylimidazole or 1-propyl-3-methylimidazole.

7. The method for preparing a self-healing electrolyte having multiple disulfide dynamic bonds according to claim 1, wherein: In step (2), the added amounts of lithium salt, ionic liquid and cross-linking agent are all 10-30 wt%.

8. A self-healing electrolyte with multiple disulfide dynamic bonds obtained by the method for preparing a self-healing electrolyte with multiple disulfide dynamic bonds according to any one of claims 1 to 7.

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