Crosslinker for Electrolyte to Enhance Battery Safety

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Solution Overview

Problem

Commercial lithium-ion batteries face safety issues due to volatile and flammable liquid electrolytes, mechanical weakness of solid polymer electrolytes, and lithium dendrite formation at high current densities, which can lead to overheating, explosions, and reduced battery performance.

Innovation Solution

A crosslinker of formula (I) is introduced, comprising a monovalent imidazolium, triazolium, pyridinium, or ammonium ion, with specific alkylene or polyethoxy groups, and halogen-containing anions, which improves the mechanical strength and ionic conductivity of the electrolyte by forming a dense crosslinked structure, acting as a localized anion reservoir to alleviate charge imbalance and prevent lithium dendrite formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid polymer electrolytes are used, then safety is improved, but mechanical strength deteriorates due to puncture susceptibility

Engineering Contradiction:

ImprovesafetyVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the physical and chemical parameters of the solid polymer electrolyte by introducing crosslinking reactions. The crosslinking degree and network density are adjusted to optimize both mechanical strength and safety, transforming the material properties to resolve the contradiction.

Inventive Principle:

Principle #35Parameter changes

2Strength

If crosslinker is added to improve mechanical strength, then mechanical strength is improved, but lithium dendrite formation worsens due to charge imbalance

Engineering Contradiction:

Improvemechanical strengthVSAvoidlithium dendrite formation

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform crosslinking distribution and incorporating localized ionic conductivity enhancers. The crosslinking density is optimized in different regions to simultaneously provide mechanical strength where needed and maintain ionic transport pathways to prevent dendrite formation.

Inventive Principle:

Principle #3Local quality

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 crosslinked electrolyte composition enhances thermal stability, mechanical strength, and ionic conductivity, significantly improving the electrochemical stability and long-term charge-discharge cycling of lithium-ion batteries, while maintaining high capacity and extending service life.

Implementation Method 1

a polymer crosslinked by the crosslinker of formula (I), wherein the polymer is obtained from a reaction between a reactive monomer having an alkenyl or a sulfhydryl group and an initiator

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

introducing a crosslinker... for improving its mechanical strength... forms a dense crosslinked structure

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

acts as a localized anion reservoir to alleviate charge imbalance and prevent lithium dendrite formation

Methodology Applied

Scientific EffectIon reservoir effect: Absorption (physical)

Data Source

PatentUS20230231189A1Crosslinker for electrolyte, electrolyte compositions and lithium-ion battery including the same

Publication Date: 2023.07.20 NAT CHENG KUNG UNIV

AI summary

The present invention provides a crosslinker of formula (I) for electrolytes, and a electrolyte composition and a lithium-ion battery including the same, wherein M, R and X are as defined in the description. With the crosslinker of formula (I), not only the mechanical strength, heat resistance, ionic conductivity and electrochemical stability of the prepared electrolyte composition are improved, but also the long-term charge-discharge cycling stability of the lithium-ion battery is improved. The crosslinker has high industrial value.