Segmented Polymer Electrolyte for High-Temperature Fuel Cells

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Solution Overview

Problem

Conventional polymer electrolytes for fuel cells have low softening temperatures, making it difficult to operate fuel cells at high temperatures and reducing durability, while high-temperature sulfonic acid polymers are expensive and challenging to produce.

Innovation Solution

A polymer electrolyte material with a phase-separated structure, comprising a segment with ion exchange groups and a fluoropolymer segment without ion exchange groups, is developed, allowing for high softening temperatures and improved durability through graft copolymerization and radiation-induced grafting of perfluoromonomers with alicyclic structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional sulfonic acid polymers are used as electrolyte material, then the fuel cell can operate at low temperatures, but the softening temperature is low (around 80°C) and high-temperature operation is not achievable

Engineering Contradiction:

Improvesoftening temperatureVSAvoidchemical durability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The polymer electrolyte is segmented into distinct functional regions: hydrophobic fluoropolymer backbone segments providing mechanical strength and heat resistance, and hydrophilic segments containing ion exchange groups for proton conduction. This segmentation allows the material to achieve both high softening temperature and chemical durability simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite polymer structures combining fluoropolymer backbones with grafted sulfonic acid-containing side chains. The fluoropolymer provides thermal stability and chemical inertness, while the grafted sulfonic acid groups provide ion conductivity, achieving both high softening temperature and chemical durability.

Inventive Principle:

Principle #40Composite materials

2Temperature

If sulfonic acid polymers with high softening temperature are used, then high-temperature operation becomes possible, but the production cost increases and manufacturing becomes difficult

Engineering Contradiction:

Improvesoftening temperatureVSAvoidproduction difficulty

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The fluoropolymer backbone is prepared in advance with stable, well-defined structures before grafting the sulfonic acid-containing side chains. This preliminary preparation of the fluoropolymer matrix simplifies the overall manufacturing process while ensuring high softening temperature characteristics.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention adjusts the grafting density, side chain length, and sulfonic acid group concentration to optimize both the softening temperature and manufacturability. By controlling these parameters, the material achieves high-temperature performance without excessive production complexity.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If conventional polymers are used for electrolyte membranes, then the structure is simple, but the heat resistance is insufficient for high-temperature operation

Engineering Contradiction:

Improveheat resistanceVSAvoidpolymer structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The polymer structure is segmented into a simple fluoropolymer backbone and functional side chains, separating the heat resistance function (backbone) from the ion conduction function (side chains). This segmentation achieves high heat resistance while maintaining reasonable structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fluoropolymer backbone provides localized heat resistance and structural stability, while the grafted side chains provide localized ion conduction functionality. This local quality differentiation allows the material to achieve high heat resistance without requiring complex overall structure.

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 polymer electrolyte material achieves high chemical durability and softening temperatures, enabling fuel cells to operate effectively at elevated temperatures with enhanced durability and reduced production costs.

Implementation Method 1

a polymer containing a segment A of a polymer containing repeating units based on a perfluoromonomer having an ion exchange group

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

Methodology Applied

Scientific EffectGraft copolymerization: Chemical Bonding

Implementation Method 3

radiation-induced grafting of perfluoromonomers with alicyclic structures

Methodology Applied

Scientific EffectRadiation-induced grafting: Radiation

Data Source

PatentUS7910236B2Electrolyte material, electrolyte membrane and membrane-electrolyte assembly for polymer electrolyte fuel cells

Publication Date: 2011.03.22 AGC INC

AI summary

To provide an electrolyte material for polymer electrolyte fuel cells having a high softening temperature and being excellent in durability, and an electrolyte membrane and a process for producing a membrane-electrode assembly using it.An electrolyte material made of a polymer containing a segment A of a polymer containing repeating units based on a perfluoromonomer having an ion exchange group and having a polymerizable double bond, at least one of carbon atoms in the polymerizable double bond being a carbon atom contained in an alicyclic structure, and a segment B of a fluoropolymer containing substantially no ion exchange group, and an electrolyte membrane and a membrane-electrode assembly using it.