SPEKK Polymer Electrolyte for High-Temperature Fuel Cells

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Solution Overview

Problem

Conventional polymer electrolyte membranes in PEMFCs experience a significant decrease in ionic conductivity at temperatures above 100°C due to moisture loss, making it difficult to operate fuel cells efficiently at high temperatures without humidification or pressurization, which increases system size and weight.

Innovation Solution

A polymer electrolyte membrane composed of sulfonated poly(ether ketone ketone) (SPEKK) cross-linked with a cross-linking agent, doped with phosphoric acid or solid inorganic proton conductors, which maintains high ionic conductivity even at low relative humidity and prevents phosphoric acid leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional polymer electrolyte membrane is used, then the fuel cell can operate at low temperatures (below 100°C), but the ionic conductivity decreases significantly at temperatures above 100°C due to moisture loss

Engineering Contradiction:

Improveoperating temperatureVSAvoidionic conductivity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the polymer electrolyte membrane by incorporating sulfonated poly(ether ketone ketone) with specific sulfonation degrees and combining it with phosphoric acid doping. This compositional parameter change enables the membrane to maintain high ionic conductivity at elevated temperatures (up to 200°C) without relying on moisture, thus resolving the contradiction between operating temperature and ionic conductivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer electrolyte membrane by combining sulfonated poly(ether ketone ketone) with phosphoric acid and potentially solid inorganic proton conductors. This composite structure synergistically combines the thermal stability of the polymer backbone with the high ionic conductivity of phosphoric acid, enabling stable operation at high temperatures while preventing acid leakage

Inventive Principle:

Principle #40Composite materials

2Temperature

If a humidification apparatus or pressurizing system is added to maintain ionic conductivity at high temperatures, then the operating temperature can be increased, but the system size and weight increase

Engineering Contradiction:

Improveoperating temperatureVSAvoidsystem size and weight

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent enables the polymer electrolyte membrane to self-maintain its ionic conductivity at high temperatures through its intrinsic phosphoric acid doping mechanism, without requiring external humidification apparatus or pressurizing systems. The membrane structure itself provides the necessary properties to prevent moisture loss and maintain proton conductivity, thus eliminating additional system components and reducing overall system size and weight

Inventive Principle:

Principle #25Self-service

3Reliability

If phosphoric acid is impregnated in the electrolyte to maintain ionic conductivity, then high temperature operation is enabled, but phosphoric acid may leak from the cell during long-term use

Engineering Contradiction:

Improveionic conductivity at high temperatureVSAvoidphosphoric acid leakage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent creates a composite structure where phosphoric acid is impregnated within the sulfonated poly(ether ketone ketone) matrix. The sulfonated polymer structure provides a stable framework that anchors the phosphoric acid, preventing its leakage during long-term operation while maintaining high ionic conductivity. The composite design ensures both high temperature performance and substance retention

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent achieves uniform distribution and strong anchoring of phosphoric acid within specific regions of the polymer matrix through controlled impregnation. The sulfonated groups in the polymer create localized high-affinity sites that firmly hold phosphoric acid molecules, preventing their migration and leakage while maintaining localized high ionic conductivity regions

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 SPEKK-based membrane maintains high ionic conductivity at elevated temperatures, reducing the need for humidification and preventing phosphoric acid leakage, thus enabling efficient operation of PEMFCs at higher temperatures without the drawbacks of conventional systems.

Implementation Method 1

The polymer electrolyte membrane acts as an ionic conductor for the migration of protons from the anode to the cathode

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

doped with phosphoric acid or solid inorganic proton conductors, which maintains high ionic conductivity even at low relative humidity

Methodology Applied

Scientific EffectProton conduction: Conduction (electrical)

Implementation Method 3

A polymer electrolyte membrane composed of sulfonated poly(ether ketone ketone) (SPEKK) cross-linked with a cross-linking agent

Methodology Applied

Scientific EffectCross-linking: Chemical Bonding

Data Source

PatentUS7648652B2Polymer electrolyte and fuel cell employing the same

Publication Date: 2010.01.19 SAMSUNG SDI CO LTD

AI summary

A polymer electrolyte that may be used in a fuel cell includes sulfonated polyether ketone ketone and a cross-linking agent.