Crosslinked Polymer Electrolyte Composition for Safer Li-Ion Batteries

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Solution Overview

Problem

Existing lithium secondary batteries face challenges with liquid electrolytes that can lead to leakage and explosion risks, and solid polymer electrolytes need improvements in interfacial resistance and ionic conductivity for better performance.

Innovation Solution

A composition for a polymer electrolyte containing a lithium salt, organic solvent, and a polymerizable oligomer with specific structures (Formulas 1 and 2) that form crosslinks during polymerization, enhancing mechanical properties and ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If liquid electrolyte is used in lithium ion battery, then high capacity is achieved, but leakage and explosion risks occur

Engineering Contradiction:

ImprovecapacityVSAvoidsafety

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent transitions the electrolyte from liquid phase to solid polymer phase. The solid polymer electrolyte maintains ionic conductivity while eliminating the safety hazards associated with liquid electrolytes such as leakage and explosion risks.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent uses composite materials by combining polymer matrices with lithium salts to create solid polymer electrolytes. This composite approach maintains the beneficial properties of both components while achieving improved safety and performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If gel polymer electrolyte is used, then stability is improved, but ionic conductivity is limited

Engineering Contradiction:

ImprovestabilityVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes key parameters of the polymer electrolyte system by using specific polymerizable oligomers with controlled molecular weights and functional groups. These parameter changes optimize both stability and ionic conductivity simultaneously.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces local quality variations through crosslinking structures and specific functional groups in the polymer chains. This creates regions with enhanced ionic conductivity while maintaining overall structural stability.

Inventive Principle:

Principle #3Local quality

3Reliability

If solid polymer electrolyte is used, then safety is improved, but interfacial resistance is high

Engineering Contradiction:

ImprovesafetyVSAvoidinterfacial resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by incorporating surface treatment and interfacial modification steps during electrolyte preparation. This reduces interfacial resistance between the solid polymer electrolyte and electrodes before battery operation begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary substances or surface layers at the interface between the solid polymer electrolyte and electrodes. These intermediaries facilitate better contact and reduce interfacial resistance while maintaining the safety benefits of solid electrolytes.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Strength

If crosslinking is increased in polymer electrolyte, then mechanical properties are improved, but ionic conductivity may decrease

Engineering Contradiction:

Improvemechanical propertiesVSAvoidionic conductivity

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating localized crosslinking regions rather than uniform crosslinking throughout the polymer matrix. This maintains mechanical strength in crosslinked regions while preserving ionic conductivity pathways in non-crosslinked regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies partial crosslinking rather than complete crosslinking of the polymer matrix. This partial action provides sufficient mechanical reinforcement while leaving enough uncrosslinked segments to maintain ionic conductivity.

Inventive Principle:

Principle #16Partial or excessive action

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 polymer electrolyte achieves high oxidation stability and ionic conductivity, leading to improved performance in lithium secondary batteries with reduced interfacial resistance and enhanced safety.

Implementation Method 1

a polymerizable oligomer which includes at least one of an oligomer represented by Formula 1 and an oligomer represented by Formula 2, and forms an excellent crosslink during a polymerization reaction

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3846272B1Composition for polymer electrolyte and lithium secondary battery including polymer electrolyte prepared therefrom

Publication Date: 2025.07.30 LG ENERGY SOLUTION LTD

AI summary

The present invention relates to a composition for a polymer electrolyte which includes a polymerizable oligomer capable of forming an excellent crosslink during a polymerization reaction. Also, the present invention relates to a polymer electrolyte, which may ensure high oxidation stability and ionic conductivity by using the composition for a polymer electrolyte, and a lithium secondary battery including the same.