Mixed-Conducting Solid Electrolyte for Low-Resistance Interfaces

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Solution Overview

Problem

Existing all-solid-state batteries face limitations in ion conductivity and electrical conductivity due to high interfacial resistance in solid electrolytes, hindering improvements in energy density and lifetime.

Innovation Solution

A solid electrolyte comprising a mixed conducting polymer, ceramic, and lithium salt, specifically poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS), combined with ceramics like TiO2 and lithium salts like LiTFSI, is used to reduce interfacial resistance and enhance conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid electrolyte is used to improve safety, then interfacial resistance increases, but this reduces ion conductivity and electrical conductivity

Engineering Contradiction:

ImprovesafetyVSAvoidinterfacial resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a polymer electrolyte layer as an intermediary between the electrode and the solid electrolyte layer. This polymer layer acts as a buffer that reduces interfacial resistance by providing good contact and compatibility between the electrode and the rigid solid electrolyte. The polymer electrolyte's flexible structure allows it to conform to the electrode surface, minimizing voids and improving interfacial adhesion, thereby reducing resistance without compromising safety.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If Li metal or Li alloy is used as negative electrode material to improve energy density, then safety risks increase due to potential decomposition reactions

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses a composite electrolyte structure that combines polymer and solid electrolyte materials to create a stable interface with Li metal or Li alloy negative electrodes. The solid electrolyte layer (LLZO) provides high stability and prevents direct contact between the polymer electrolyte and Li metal, eliminating decomposition reactions. Meanwhile, the polymer electrolyte layer ensures good ion transport, allowing the use of high-capacity Li metal or Li alloy negative electrodes to achieve high energy density without safety risks.

Inventive Principle:

Principle #40Composite 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 solid electrolyte improves adhesive force and strength, resulting in enhanced ion and electrical conductivity, thereby improving the performance and lifetime of all-solid-state batteries.

Implementation Method 1

a mixed conducting polymer having mixed conducting properties including ion conductivity and electrical conductivity

Methodology Applied

Scientific EffectMixed conduction:

Implementation Method 2

The solid electrolyte improves adhesive force and strength

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

a lithium salt, wherein the mixed conducting polymer comprises poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS)

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4329034B1Solid electrolyte and method for producing same

Publication Date: 2026.02.04 LG ENERGY SOLUTION LTD

Figure 1

AI summary

The present invention relates to a solid electrolyte and a method for producing same, and, more specifically, the solid electrolyte has an increased adhesive force and strength by comprising an inorganic matter and a mixed conductive polymer having ionic conductivity and electrical conductivity characteristics, and, thereby, interface resistance is reduced and ionic conductivity and electrical conductivity can be improved.