Porous Composite Electrolyte Membrane for Stable LLZO Ion Conduction

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Solution Overview

Problem

Existing organic electrolytes in lithium secondary batteries face issues with flammability, corrosiveness, thermal instability, and reduced ion conductivity due to side reactions on the surface of oxide-based inorganic electrolytes like LLZO, which also affect mechanical strength and surface properties.

Innovation Solution

A porous organic-inorganic composite electrolyte membrane is developed, comprising an oxide-based inorganic electrolyte embedded in a fluorine-based polymer matrix, with controlled surface ratios and crystal structure to suppress side reactions, ensuring high ion conductivity and excellent mechanical and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an oxide-based inorganic electrolyte (LLZO) is used to achieve high ion conductivity and thermal stability, then ion conductivity and thermal stability are improved, but surface properties deteriorate due to side reactions on the surface

Engineering Contradiction:
Improveion conductivityVSAvoidsurface properties
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material consisting of oxide-based inorganic electrolyte particles embedded in a fluorine-based polymer matrix. This composite structure combines the high ion conductivity of the inorganic electrolyte with the excellent surface properties and stability of the fluorine-based polymer, thereby resolving the contradiction between improved ion conductivity and deteriorated surface properties.

Inventive Principle:
Principle #40Composite materials

2Temperature

If an oxide-based inorganic electrolyte is used to achieve thermal stability, then thermal stability is improved, but mechanical strength deteriorates due to insufficient surface properties

Engineering Contradiction:
Improvethermal stabilityVSAvoidmechanical strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The fluorine-based polymer matrix provides excellent mechanical strength and flexibility, while the embedded oxide-based inorganic electrolyte particles maintain thermal stability. The composite structure allows the material to simultaneously achieve high thermal stability and improved mechanical strength that would be impossible with the inorganic electrolyte alone.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If a solid electrolyte is applied to solve safety issues of organic electrolytic solution, then safety is improved, but manufacturing complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidmanufacturing process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a porous fluorine-based polymer matrix that can be easily formed through conventional polymer processing techniques. The porous structure allows simple infiltration of the inorganic electrolyte particles and maintains good contact with electrodes. This approach enables manufacturing of solid electrolyte with safety benefits while avoiding the complex sintering and high-temperature processing required for dense inorganic electrolytes.

Inventive Principle:
Principle #31Porous materials

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 composite electrolyte membrane enhances battery performance with improved life characteristics and high-rate characteristics, offering stable ion conductivity and mechanical strength while reducing surface reactions.

Implementation Method 1

effectively suppressing a side reaction on the surface of an oxide-based inorganic electrolyte

Methodology Applied
Scientific EffectSurface reaction suppression:

Implementation Method 2

high ion conductivity

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP4708432A1Porous organic-inorganic composite electrolyte membrane, manufacturing method therefor, and lithium secondary battery comprising same
Publication Date: 2026.03.11 SK ON CO LTD
  • EP4708432A1 patent drawingFigure 1
  • EP4708432A1 patent drawingFigure 2(a)~2(b)
  • EP4708432A1 patent drawingFigure 3(a)~3(h)

AI summary

The present disclosure relates to a porous organic-inorganic composite electrolyte membrane, an organic-inorganic composite electrolyte comprising the porous organic-inorganic composite electrolyte membrane, a secondary battery comprising the porous organic-inorganic composite electrolyte membrane, and a method for manufacturing the porous organic-inorganic composite electrolyte membrane, the porous organic-inorganic composite electrolyte membrane comprising an oxide-based inorganic electrolyte and a fluorine-based polymer matrix, wherein the oxide-based inorganic electrolyte is contained in the fluorine-based polymer matrix, and, in the X-ray photoelectron spectroscopy (XPS) analysis result of the surface, the ratio (SCO3/SZr) of the area (SCO3) of a peak corresponding to CO3 in the C1s spectrum to the area (SZr) of a peak corresponding to Zr3d5/2 in the Zr3d spectrum is greater than 0 and less than or equal to 5.0.