Cross-Linked Polyrotaxane Solid Electrolyte for Safe Ion Conduction

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Solution Overview

Problem

Lithium secondary batteries face challenges with liquid electrolytes due to electrode material deterioration, volatility, combustion risks, and limited ion conductivity of solid electrolytes, which affect their stability and performance in diverse environments.

Innovation Solution

A solid electrolyte composition incorporating a polyrotaxane compound, a cross-linking agent, and a lithium salt, thermally cured to enhance ion conductivity and mechanical properties, forming a flexible and stable electrolyte for improved lithium secondary battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid electrolyte is used, then ion conductivity is high, but safety deteriorates due to combustion risk and volatility

Engineering Contradiction:
ImprovesafetyVSAvoidion conductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the physical state parameter of the electrolyte from liquid to solid by using cross-linked polyrotaxane gel, thereby eliminating combustion risk and volatility while maintaining functional performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite gel electrolyte system combining polyrotaxane polymer matrix with lithium salt and cross-linking agents, achieving both safety of solid and ion conductivity of liquid through synergistic material combination

Inventive Principle:
Principle #40Composite materials

2Reliability

If a solid electrolyte is used, then safety is improved, but ion conductivity deteriorates at room temperature

Engineering Contradiction:
ImprovesafetyVSAvoidion conductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the molecular structure parameter by introducing cross-linking bonds in the polyrotaxane gel, creating a three-dimensional network that facilitates ion transport pathways while maintaining solid-state safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a gel phase that exhibits properties intermediate between solid and liquid, allowing ion mobility characteristic of liquids while maintaining the structural stability and safety of solids

Inventive Principle:
Principle #36Phase transitions

3Productivity

If ion conductivity of solid electrolyte is increased, then productivity is improved, but electrochemical window deteriorates

Engineering Contradiction:
Improveion conductivityVSAvoidelectrochemical window
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the cross-linking density parameter to achieve a balance between ion conductivity and electrochemical stability, preventing excessive cross-linking that would reduce the electrochemical window

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates localized ion transport channels within the cross-linked gel structure, allowing high ion conductivity in specific regions while maintaining overall electrochemical stability of the bulk material

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 solution provides a solid electrolyte with enhanced flexibility, tensile strength, and ion conductivity, leading to improved stability and performance of lithium secondary batteries, addressing the limitations of existing electrolytes.

Implementation Method 1

a cross-linking agent, a lithium salt, and an organic solvent, wherein the cross-linking agent includes a compound represented by Formula 1 below and a compound represented by Formula 2

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

a lithium salt, and an organic solvent

Methodology Applied
Scientific EffectIon dissociation: Ionisation

Implementation Method 3

a method for preparing a solid electrolyte for a lithium secondary battery including thermal-curing the composition for preparing a solid electrolyte

Methodology Applied
Scientific EffectThermal curing: Heating

Data Source

PatentEP4160770B1Composition for preparing solid electrolyte, and solid electrolyte and lithium secondary battery using the same
Publication Date: 2024.11.20 LG ENERGY SOLUTION LTD
  • EP4160770B1 patent drawingFigure 1(a)~2(b)
  • EP4160770B1 patent drawingFigure 3~4
  • EP4160770B1 patent drawingFigure 5(a)~5(b)

AI summary

The present invention relates to a composition for preparing a solid electrolyte including a polyrotaxane compound, a cross-linking agent, a lithium salt, and an organic solvent, wherein the cross-linking agent includes a compound represented by Formula 1 and a compound represented by Formula 2, a method for preparing a solid electrolyte for a lithium secondary battery including thermal-curing the composition, a solid electrolyte for a lithium secondary battery including a thermo-cured product of the composition, and a lithium secondary battery including the solid electrolyte.