CN-121545924-B - Polymer gel electrolyte and preparation method thereof

CN121545924BCN 121545924 BCN121545924 BCN 121545924BCN-121545924-B

Abstract

The invention discloses a polymer gel electrolyte and a preparation method thereof, and relates to the technical field of polymer electrolytes. The invention realizes the polymer network structure of 'both rigid and soft' through ternary polymerization design of Acrylic Acid (AA), butyl Acrylate (BA) and acrylic acid-2-ethylhexyl ester (2-EHA). The butyl acrylate and the 2-ethylhexyl acrylate are used as flexible units, long-chain alkyl ester groups are introduced, and the segment movement capacity is increased, so that the flexibility and the deformation recovery capacity of the electrolyte are improved. The introduction of the flexible chain segment increases the free volume, optimizes the ion transmission channel and improves the ion conductivity.

Inventors

FENG LANLAN
LI BAOHUA
ZHENG YUNSHAN
WANG YIMING

Assignees

清华大学深圳国际研究生院

Dates

Publication Date: 20260512
Application Date: 20260121

Claims (7)

1. A polymer gel electrolyte, comprising: A polymer network which is a terpolymer network formed by copolymerization of acrylic acid monomer, butyl acrylate monomer and 2-ethylhexyl acrylate monomer; Wherein, the acrylic acid unit is used as a rigid unit to provide carboxyl to enhance interfacial adhesion, the butyl acrylate and the 2-ethylhexyl acrylate unit are used as a flexible unit to introduce long chain alkyl ester groups to increase the movement capacity and free volume of chain segments, and the ion transmission channel is optimized; And an ion conducting medium impregnated in the polymer network; The polymer network is a crosslinked network formed by crosslinking with a crosslinking agent; The cross-linking agent is N, N' -methylene bisacrylamide; The mole fraction of the acrylic acid monomer is 20% -50%, the mole fraction of the butyl acrylate monomer is 10% -60% and the mole fraction of the acrylic acid-2-ethylhexyl ester monomer is 10% -60% based on the total monomer mole number of the terpolymer network.
2. The polymer gel electrolyte of claim 1, wherein the ion-conducting medium is an acid solution, an alkali solution, or a salt solution.
3. The polymer gel electrolyte of claim 2, wherein the ion-conducting medium is a sulfuric acid solution, a phosphoric acid solution, a potassium hydroxide solution, or a lithium chloride solution.
4. A supercapacitor comprising a positive electrode, a negative electrode and an electrolyte disposed between the positive electrode and the negative electrode, wherein the electrolyte is the polymer gel electrolyte of any one of claims 1 to 3.
5. A method for preparing the polymer gel electrolyte according to any one of claims 1 to 3, comprising the steps of: s100, providing a mixed solution, wherein the mixed solution comprises an acrylic acid monomer, a butyl acrylate monomer, a 2-ethylhexyl acrylate monomer, a cross-linking agent, an initiator and an ion conductive medium; s200, carrying out deoxidization treatment on the mixed solution; and S300, heating the mixed solution to an initiation temperature and for a sufficient time under an inert atmosphere or a vacuum environment to initiate a monomer polymerization reaction, so as to form the polymer gel electrolyte.
6. The method of claim 5, wherein the ion conducting medium is an aqueous sulfuric acid solution having a concentration of 1m to 5m.
7. The method of claim 5, wherein the initiation temperature is 60 ℃ to 95 ℃ and the holding time is 6 hours to 24 hours.

Description

Polymer gel electrolyte and preparation method thereof Technical Field The invention relates to the technical field of polymer electrolytes, in particular to a polymer gel electrolyte with a molecular structure design and a multipolymer and a preparation method and application thereof. Background The super capacitor (Supercapacitor, SC) has wide application in the fields of consumer electronics, new energy automobiles, smart grids and the like due to high power density, rapid charge and discharge capability and long cycle life. A key component of wearable electronic devices is a flexible supercapacitor, whose core challenge is how to maintain the stability and ion transport efficiency of the interface between the electrode and the electrolyte under repeated mechanical deformations such as bending, folding or stretching. Currently, flexible supercapacitors often employ liquid electrolytes or semi-solid gel electrolytes, but the interfacial adhesion between these electrolytes and solid electrodes is weak. Under dynamic mechanical deformation, interfacial peeling is easy to occur, so that contact resistance is increased, an ion transmission path is blocked, and electrochemical performance attenuation such as reduction of specific capacitance, increase of internal resistance and the like is further caused. The existing polyacrylic acid (PAA) hydrogel electrolyte has certain ionic conductivity, but has large brittleness and poor flexibility, and is difficult to meet the requirement of a flexible device on mechanical durability. Therefore, there is a need to develop a polymer gel electrolyte that combines excellent interfacial adhesion, high ionic conductivity and good mechanical flexibility to enhance the overall performance of flexible supercapacitors. Disclosure of Invention The technical problem to be solved by the invention is how to provide an electrolyte for a flexible electrochemical device, which can keep the stability of electrochemical performance under dynamic mechanical deformation. In one aspect, the invention provides a polymer gel electrolyte comprising a polymer network, wherein the polymer network is a terpolymer network formed by copolymerization of acrylic acid monomer, butyl acrylate monomer and 2-ethylhexyl acrylate monomer, and an ion conducting medium immersed in the polymer network. Optionally, the ion conducting medium is an acid solution, an alkali solution or a salt solution. Alternatively, the ion conducting medium is a sulfuric acid solution, a phosphoric acid solution, a potassium hydroxide solution, or a lithium chloride solution. Alternatively, the polymer network is a crosslinked network formed by crosslinking with a crosslinking agent. Alternatively, the cross-linking agent is N, N' -methylenebisacrylamide. Optionally, the mole fraction of the acrylic acid monomer is 20% -50%, the mole fraction of the butyl acrylate monomer is 10% -60% and the mole fraction of the 2-ethylhexyl acrylate monomer is 10% -60% based on the total monomer mole number of the terpolymer network. In another aspect, the present invention provides a supercapacitor comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, the electrolyte being the polymer gel electrolyte described above. In another aspect, the invention provides a method for preparing the polymer gel electrolyte, which comprises the following steps of S100, providing a mixed solution, wherein the mixed solution comprises an acrylic acid monomer, a butyl acrylate monomer, a 2-ethylhexyl acrylate monomer, a cross-linking agent, an initiator and an ion conducting medium, S200, carrying out deoxidization treatment on the mixed solution, and S300, heating the mixed solution to an initiation temperature under inert atmosphere or vacuum environment for a sufficient time to initiate polymerization of the monomers to form the polymer gel electrolyte. Optionally, the ion conducting medium is sulfuric acid aqueous solution, and the concentration of the ion conducting medium is 1M-5M. Optionally, the cross-linking agent is N, N' -methylene bisacrylamide, and the mass of the cross-linking agent is 0.2% -3% of the total mass of the acrylic acid monomer, the butyl acrylate monomer and the acrylic acid-2-ethylhexyl ester monomer. Optionally, the initiator is ammonium persulfate, and the mass of the initiator is 0.5% -5% of the total mass of the acrylic acid monomer, the butyl acrylate monomer and the 2-ethylhexyl acrylate monomer. Optionally, the mixed solution also comprises an emulsifier, wherein the emulsifier is sodium dodecyl sulfate, and the mass of the emulsifier is 0.5% -3% of the total mass of the acrylic acid monomer, the butyl acrylate monomer and the acrylic acid-2-ethylhexyl ester monomer. Optionally, the initiation temperature is 60 ℃ to 95 ℃. Optionally, the sufficient time is maintained for 6-24 hours. The polymer gel electrolyte provided by the invention has