Ionic Liquid Gel Polymer Electrolyte for High-Voltage Battery Stability

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Solution Overview

Problem

Existing gel polymer electrolytes for lithium secondary batteries lack improved flame retardancy and oxidation resistance, especially at high temperatures and high voltages, which affects battery stability and capacity.

Innovation Solution

A gel polymer electrolyte composition for lithium secondary batteries is developed, incorporating a lithium salt, an ionic liquid, a polymerization initiator, and an oligomer, with the ionic liquid comprising 60 wt% or more, replacing non-aqueous organic solvents to enhance flame retardancy and oxidation resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid electrolyte solution including an organic solvent is used, then the battery can operate, but the organic solvent volatilizes easily and combustion occurs at high temperatures

Engineering Contradiction:
Improvebattery stabilityVSAvoidcombustion and volatilization
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by incorporating ionic liquids with specific molecular structures (Formulae 1-6) that have inherently higher thermal stability and lower volatility compared to conventional organic solvents, thereby reducing combustion risk while maintaining battery operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining ionic liquids with gel polymer matrices and lithium salts, forming a multi-component system that integrates the flame-retardant properties of ionic liquids with the structural stability of polymer gels to achieve both safety and performance

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If the driving voltage is increased to improve energy density, then the battery capacity increases, but the liquid electrolyte solution oxidizes and decomposes at high voltage of 4.3 V or more

Engineering Contradiction:
Improveenergy densityVSAvoidelectrolyte stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent modifies the electrolyte's electrochemical stability parameters by selecting ionic liquids with appropriate redox potentials and molecular structures that can withstand higher operating voltages without oxidation or decomposition, enabling safe operation above 4.3 V

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional liquid electrolyte solution (which has limited voltage tolerance) with a more stable ionic liquid-based gel polymer electrolyte system that provides long-term durability at high voltages, effectively extending the operational lifespan of the battery under high-energy-density conditions

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If a gel polymer electrolyte is used instead of liquid electrolyte solution, then electrochemical stability is improved, but flame retardancy becomes difficult to secure

Engineering Contradiction:
Improveelectrochemical stabilityVSAvoidflame retardancy
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent develops a composite electrolyte system that integrates the electrochemical stability of gel polymer matrices with the flame-retardant properties of ionic liquids, creating a multi-functional material that simultaneously achieves both stability and safety

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent designs the ionic liquid-based gel polymer electrolyte to perform multiple functions: maintaining electrochemical stability like conventional gel polymers while simultaneously providing flame retardancy, thus making the electrolyte universally suitable for both performance and safety requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 improved gel polymer electrolyte composition achieves enhanced high-temperature storage stability and oxidation resistance, thereby maintaining battery performance and preventing ignition during overcharge.

Implementation Method 1

the ionic liquid is included in an amount of 60 wt% or more based on a total weight of the gel polymer electrolyte composition for a lithium secondary battery... enhance flame retardancy and oxidation resistance

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Implementation Method 2

enhance flame retardancy and oxidation resistance... achieves enhanced high-temperature storage stability and oxidation resistance, thereby maintaining battery performance and preventing ignition during overcharge

Methodology Applied
Scientific EffectFlame retardancy: Combustion

Implementation Method 3

a gel polymer electrolyte composition for lithium secondary batteries is developed, incorporating a lithium salt, an ionic liquid, a polymerization initiator, and an oligomer

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 4

achieves enhanced high-temperature storage stability... preventing ignition during overcharge

Methodology Applied
Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentEP3694040B1Gel polymer electrolyte composition, gel polymer electrolyte prepared thereby, and lithium secondary battery including the gel polymer electrolyte
Publication Date: 2025.06.18 LG ENERGY SOLUTION LTD
  • EP3694040B1 patent drawingFigure 1
  • EP3694040B1 patent drawingFigure 2
  • EP3694040B1 patent drawingFigure 3

AI summary

The present invention relates to a gel polymer electrolyte composition and a lithium secondary battery including the same, and particularly, to a gel polymer electrolyte composition, in which flame retardancy is improved by including an ionic liquid, instead of a non-aqueous organic solvent, as well as a lithium salt, a polymerization initiator, and an oligomer having a specific structure, and a lithium secondary battery in which high-temperature stability is improved by including the same.