CN-117936892-B - Preparation method of composite plastic crystal electrolyte with molecular brush

CN117936892BCN 117936892 BCN117936892 BCN 117936892BCN-117936892-B

Abstract

The invention relates to a preparation method and application of a composite plastic crystal electrolyte with a molecular brush. The invention belongs to the technical field of electrolyte materials. The composite plastic crystal polymer electrolyte material with molecular brush is characterized by that it is formed from diaphragm with molecular brush and plastic crystal electrolyte obtained by in-situ polymerization, in which the mixed solution of polymer monomer, lithium salt, additive and plastic crystal material is heated so as to obtain the invented plastic crystal electrolyte. The invention aims to solve the problem of uncontrollable side reaction in the plastic crystal electrolyte, thereby realizing that the assembled battery can stably circulate for a long time at room temperature. The preparation method comprises (1) preparing a membrane with a molecular brush, and (2) preparing a mixed solution of a polymer monomer, lithium salt and a plastic crystal material and mixing the mixed solution with the treated membrane. The invention has the advantages of simple preparation process, good mechanical strength, long cycle life of assembled batteries, and the like.

Inventors

PAN QINMIN
LI YUXUAN

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260512
Application Date: 20240312

Claims (8)

1. The preparation method of the composite plastic crystal electrolyte with the molecular brush is characterized by comprising the following steps of: 1. The preparation of the diaphragm with the molecular brush comprises the steps of mixing 2-acrylamide-2-methylpropanesulfonic acid and lithium carbonate in N, N-dimethylformamide at room temperature, stirring for 10-60 min, adding the diaphragm subjected to ultraviolet/ozone treatment for 0.5-2h into the solution, adding dibenzoyl peroxide, 2-bipyridine, copper chloride and toluene, stirring for 6-16 h under an argon environment, and then taking out, cleaning and drying the diaphragm, wherein the mass ratio of the 2-acrylamide-2-methylpropanesulfonic acid to the lithium carbonate is (6-4): 1, the mass ratio of the dibenzoyl peroxide, the 2, 2-bipyridine and the copper chloride is (20-15): 8-4): 1, and the mass ratio of the N, N-dimethylformamide to the toluene is (8~4): 1; 2. The preparation of the composite plastic crystal electrolyte with the molecular brush and the application thereof in the battery are that a polymer monomer, lithium salt, an additive and a plastic crystal material are mixed and stirred for 0.5 to 1 hour, azodiisobutyronitrile is added into the mixture, the mixture is dropwise added on a treated diaphragm after being stirred and completely dissolved, an electrode is stacked and assembled into the battery, the assembled battery is heated for 0.5 to 1 hour at the temperature of 40 to 100 ℃, and the plastic crystal material is succinonitrile.
2. The preparation method of the composite plastic crystal electrolyte with the molecular brush according to claim 1, wherein the mass ratio of the 2-acrylamide-2-methylpropanesulfonic acid to the lithium carbonate is 5.4:1.
3. The preparation method of the composite plastic crystal electrolyte with the molecular brush, which is disclosed in claim 1, is characterized in that the mass ratio of dibenzoyl peroxide, 2-bipyridine and copper chloride is 18:4:1.
4. The method for preparing a composite plastic crystal electrolyte with a molecular brush according to claim 1, wherein the polymer monomer is one or two of ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, polyethylene glycol methyl ether methacrylate and methyl acrylate.
5. The preparation method of the composite plastic crystal electrolyte with the molecular brush according to claim 1, wherein the lithium salt is one or a mixture of a plurality of lithium hexafluorophosphate, lithium bis (trifluoromethanesulfonyl) imide and lithium bis (oxalato) borate.
6. The method for preparing the composite plastic crystal electrolyte with the molecular brush according to claim 1, wherein the additive is one or a mixture of more of fluoroethylene carbonate, ethylene thiocarbonate and methyl trifluoroethyl carbonate.
7. The method for preparing a composite plastic crystal electrolyte with a molecular brush according to claim 1, wherein the plastic crystal material is succinonitrile.
8. The method for preparing a composite plastic crystal electrolyte with a molecular brush according to any one of claims 1 to 6, wherein the amount of lithium salt is 0.2 to 2 times the mass of the polymer monomer, the amount of plastic crystal material is 0.05 to 2 times the mass of the polymer monomer, and the amount of additive is 0.1 to 1 times the mass of the polymer monomer.

Description

Preparation method of composite plastic crystal electrolyte with molecular brush Technical Field The invention belongs to the technical field of electrolyte materials, and particularly relates to a preparation method and application of a composite plastic crystal electrolyte. Background With the gradual becoming of the indispensable part of people's life of products such as electric motor car, cell-phone, the demand of this characteristic of battery high energy density is becoming more and more strong. However, as the energy density of the battery increases, particularly in the case of using an electrolyte, the safety problem of the battery becomes uncontrollable. In order to solve the problem of battery safety, solid-state electrolytes, in particular polymer solid-state electrolytes, are increasingly becoming an alternative to combustible electrolytes. However, solid electrolytes often suffer from low conductivity and narrow windows. The plastic crystal electrolyte is used as a polymer solid electrolyte, has higher ionic conductivity, wide window and excellent thermal stability, but side reaction between the plastic crystal electrolyte and a lithium negative electrode limits the application of the plastic crystal electrolyte in solid batteries. One of the methods commonly used at present for alleviating side reactions between the plastic crystal electrolyte and the lithium negative electrode is to introduce a polymer network into the plastic crystal electrolyte for fixation (such as CN 116247289A), but the introduction of the polymer can reduce the conductivity of the electrolyte to a certain extent. The introduction of fillers to fix (e.g., CN 113410523A) is also a common method, but the introduction of fillers may initiate polymerization of the crystallites at the filler surface. Disclosure of Invention The invention aims to solve the problems of uncontrollable side reactions and the like in a plastic crystal electrolyte, and provides a composite plastic crystal polymer electrolyte which has higher ionic conductivity, wide chemical stability window and good mechanical strength, and an assembled battery can still have good circulation performance under a larger current density. The preparation method of the composite plastic crystal electrolyte with the molecular brush is carried out according to the following steps: 1. Preparation of a membrane with molecular brush 2-acrylamido-2-methylpropanesulfonic acid and lithium carbonate were mixed in N, N-dimethylformamide at room temperature and stirred for 10-60 min. Then adding the membrane treated by ultraviolet/ozone for 0.5-2h into the solution, adding dibenzoyl peroxide, 2-bipyridine, copper chloride and toluene, and stirring for 6-16 h under the argon environment. Then, the diaphragm is taken out, washed and dried for further experiment. Wherein the mass ratio of the 2-acrylamide-2-methylpropanesulfonic acid to the lithium carbonate is (6-4) 1, the mass ratio of the dibenzoyl peroxide, the 2, 2-bipyridine and the copper chloride is (20-15) 1, and the mass ratio of the N, N-dimethylformamide to the toluene is (8-4) 1; 2. The preparation of the composite plastic crystal electrolyte with the molecular brush and the application thereof in the battery are that the polymer monomer, the lithium salt, the additive and the plastic crystal material are mixed and stirred for 0.5 to 1 hour, the azodiisobutyronitrile is added into the mixture, the mixture is dropwise added on the treated diaphragm after being stirred and completely dissolved, and the electrode stack is assembled into the battery. The assembled battery is heated at 40-100 ℃ for 0.5-1h. The composite plastic crystal polymer electrolyte material with the molecular brush can also adopt the following technical scheme: The composite plastic crystal electrolyte with the molecular brush is characterized in that the polymer monomer is one or two of ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, polyethylene glycol methyl ether methacrylate and methyl acrylate. The composite plastic crystal electrolyte with the molecular brush is characterized in that the lithium salt is one or a mixture of more of lithium hexafluorophosphate, lithium bis (trifluoromethanesulfonyl) imide and lithium bis (oxalato) borate. The composite plastic crystal electrolyte with the molecular brush is characterized in that the additive is one or a mixture of more of fluoroethylene carbonate, thiocarbonate and methyl trifluoroethyl carbonate. The composite plastic crystal electrolyte with the molecular brush is characterized in that the plastic crystal material is succinonitrile. The composite plastic crystal electrolyte with the molecular brush is characterized in that the lithium salt dosage is 0.2-2 times of the mass of the polymer monomer, the plastic crystal material is 0.05-2 times of the mass of the polymer matrix, and the additive is 0.1-1 times of the mass of the polymer matrix. The invention has the ad