Fluorescent PEO Polymer Electrolyte for Interface Observation

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Solution Overview

Problem

Existing polymer electrolytes based on polyethylene oxide (PEO) suffer from low ionic conductivity and a narrow electrochemical window, limiting their application in high-voltage cathode materials, and the interface bonding situation between the electrolyte and adjacent structural layers cannot be nondestructively observed.

Innovation Solution

A polymer matrix is developed by labeling the end group of PEO with a fluorescent molecule, reducing crystallinity and enhancing electrochemical performance, allowing for nondestructive testing through fluorescence characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If PEO is used as polymer electrolyte matrix, then cost is reduced and compatibility with metallic lithium is improved, but ionic conductivity is lowered and electrochemical window is narrowed

Engineering Contradiction:

Improvecost and compatibilityVSAvoidionic conductivity and electrochemical window

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the molecular weight and composition of PEO to optimize the balance between ionic conductivity and electrochemical stability. Specifically, using PEO with controlled molecular weight parameters enables the electrolyte to achieve sufficient ionic conductivity while maintaining compatibility with lithium metal and expanding the electrochemical window for high-voltage applications.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining PEO with ceramic fillers (such as Al2O3, SiO2, or TiO2 particles) and lithium salts to create a composite polymer electrolyte. This composite structure enhances ionic conductivity through the ceramic filler pathways while PEO provides flexibility and lithium compatibility, simultaneously expanding the electrochemical window.

Inventive Principle:

Principle #40Composite materials

2Reliability

If solid electrolytes are used to replace liquid electrolyte solutions, then safety is improved and energy density is increased, but interface bonding observation capability is lost

Engineering Contradiction:

Improvesafety and energy densityVSAvoidinterface bonding observation

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies color changes by incorporating fluorescent markers or color-indicating materials into the solid electrolyte interface layers. These fluorescent markers emit specific wavelengths when excited, enabling optical microscopy observation of interface bonding quality between the solid electrolyte and electrode surfaces without compromising the safety or energy density benefits of solid-state batteries.

Inventive Principle:

Principle #32Color changes

3Reliability

If polymer matrix is modified to improve electrochemical performance, then ionic conductivity and electrochemical window are enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrochemical performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the electrolyte system into distinct functional layers: a PEO-based polymer matrix layer for flexibility and lithium compatibility, a ceramic filler layer for ionic conductivity enhancement, and a fluorescent marker layer for interface observation. This segmented structure allows each layer to be optimized independently while simplifying the overall manufacturing process through layer-by-layer assembly.

Inventive Principle:

Principle #1Segmentation

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 modified PEO matrix improves ionic conductivity and electrochemical window, enabling nondestructive interface observation and suppressing lithium dendrites, thus enhancing the performance of polymer electrolytes and all-solid-state batteries.

Implementation Method 1

labeling an end group of polyethylene oxide (PEO) with a fluorescent molecule

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

improves ionic conductivity

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20260049936A1Polymer matrix, polymer electrolyte, all-solid-state battery, and nondestructive testing method

Publication Date: 2026.02.19 SOUTH CHINA UNIV OF TECH

AI summary

Disclosed is a polymer matrix with both excellent electrochemical performance and fluorescence characteristics, which is obtained by labeling an end group of polyethylene oxide with a fluorescent molecule. By modifying the end group of the polyethylene oxide, crystallinity of the polymer matrix is effectively reduced, and the polymer matrix is endowed with the fluorescence characteristics, thereby providing a novel method for nondestructive testing of an electrolyte. Meanwhile, the polymer matrix of the present application can greatly improve electrochemical performance of a polymer electrolyte and suppress lithium dendrites, thereby enabling the polymer electrolyte to have a wide voltage window. Further disclosed are a polymer electrolyte including the polymer matrix, an all-solid-state battery, and a nondestructive testing method thereof. By applying the fluorescence characteristics of the polymer matrix to battery interface characterization, nondestructive testing of a battery interface is achieved.