Gel Polymer Electrolyte Composition for Stable SEI and Low Leakage

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Solution Overview

Problem

Gel polymer electrolytes suffer from inferior electrochemical properties and instability, leading to unstable device performance due to issues like liquid leakage and volatility, necessitating improvements in leakage resistance and stability while maintaining excellent electrochemical properties.

Innovation Solution

A composition for a gel polymer electrolyte incorporating lithium difluoro(oxalato) borate (LiDFOB) and acrylate- or methacrylate-based monomers with isocyanate groups is used, which forms a stable solid electrolyte interface (SEI) layer, enhancing ionic conductivity and elastic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gel polymer electrolytes are used to replace liquid electrolytes, then leakage resistance and stability are improved, but electrochemical properties deteriorate

Engineering Contradiction:

Improveleakage resistance and stabilityVSAvoidelectrochemical properties

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite gel polymer electrolyte system combining polyacrylonitrile (PAN) polymer matrix with lithium difluoro(oxalato)borate (LiDFOB) electrolyte salt and cyclic carbonate solvents. This composite structure integrates the leakage resistance and stability of gel polymers with the excellent electrochemical properties of liquid electrolytes, resolving the contradiction between reliability and electrochemical performance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including LiDFOB concentration (1-2 M), cyclic carbonate content (10-40 wt%), and polymer-to-solvent ratio to achieve the optimal balance between gel structure stability and ionic conductivity. By precisely controlling these parameters, the electrolyte maintains both high leakage resistance and excellent electrochemical properties

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If liquid electrolytes are used, then electrochemical properties are excellent, but leakage resistance and stability deteriorate

Engineering Contradiction:

Improveelectrochemical propertiesVSAvoidleakage resistance and stability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent employs a gel polymer matrix that forms a flexible yet stable network structure, effectively containing the liquid electrolyte components and preventing leakage while maintaining ionic conductivity. This gel matrix acts as a flexible shell that preserves both the electrochemical benefits of liquid electrolytes and the stability required for reliable operation

Inventive Principle:

Principle #30Flexible shells and thin films

3Stability of the object's composition

If gel polymer electrolytes are developed to improve leakage resistance, then stability is improved, but electrochemical properties become inferior

Engineering Contradiction:

ImprovestabilityVSAvoidelectrochemical properties

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces cyclic carbonate solvents (EC, DEC, EMC) as intermediary substances that facilitate ionic transport within the gel polymer matrix. These intermediaries bridge the rigid polymer structure and the ionic conduction pathways, enabling high ionic conductivity (10^-3 to 10^-2 S/cm) while maintaining the stable gel structure with excellent leakage resistance

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The composition results in a gel polymer electrolyte with improved leakage resistance, stability, and excellent electrochemical performance, including high ionic conductivity and low charge transfer resistance, leading to stable electrochemical devices.

Implementation Method 1

forms a stable solid electrolyte interface (SEI) layer, enhancing ionic conductivity

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) layer formation:

Implementation Method 2

exhibiting high ionic conductivity, low charge transfer resistance

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Data Source

PatentUS20250300223A1Composition for gel polymer electrolyte, gel polymer electrolyte and electrochemical device comprising the same

Publication Date: 2025.09.25 UNIV OF SEOUL IND COOP FOUND

AI summary

The present specification relates to a composition for a gel polymer electrolyte, a gel polymer electrolyte, and an electrochemical device including the same, and the gel polymer electrolyte according to one aspect of the present specification may simultaneously form a stable SEI layer while exhibiting high ionic conductivity, low charge transfer resistance, and elastic properties, and an electrochemical device to which such a gel polymer electrolyte is applied may exhibit high stability and excellent electrochemical performance. The gel polymer electrolyte according to one aspect of the present specification may be applied to various electrochemical devices such as lithium ion batteries and thermoelectric devices.