Gas Diffusion Electrode with Bonded Noble Metal Catalyst

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Solution Overview

Problem

Fuel cell catalyst layers face issues with agglomeration and washout of catalytic noble metals, leading to a decrease in catalytically active surface area and stability over time.

Innovation Solution

A gas diffusion electrode with a gas-permeable substrate formed from an organic polymer having functional groups capable of complexing metal cations, where catalytically active noble metal particles or atoms are bonded directly to the substrate, eliminating the need for a separate catalytic layer and preventing agglomeration through chemical attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate catalytic layer with supported noble metal particles is used, then catalytic activity can be achieved, but the noble metal particles undergo agglomeration and washout leading to decreased stability and loss of catalytically active surface area

Engineering Contradiction:

Improvestability of catalytic noble metalVSAvoidloss of noble metal through washout and agglomeration

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent merges the catalytic layer and gas diffusion layer into a single integrated gas diffusion electrode. The noble metal particles are directly incorporated into the gas diffusion layer matrix, eliminating the separate catalytic layer and its associated support structure. This integration prevents the agglomeration and washout issues that occur at the interface between separate layers.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gas diffusion layer is formulated as a composite material containing noble metal particles distributed within the gas diffusion matrix. This composite structure provides both the gas diffusion functionality and catalytic activity in a single homogeneous material, preventing the separation and degradation that occurs in multi-layer configurations.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If the catalytic noble metal is finely distributed to increase accessible surface area, then catalytic activity improves, but the noble metal becomes more susceptible to washout and agglomeration

Engineering Contradiction:

Improveaccessible surface area of catalystVSAvoidresistance to agglomeration and washout

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The gas diffusion layer is designed with locally optimized properties where noble metal particles are distributed within the gas diffusion matrix at concentrations and positions that maximize catalytic surface area while maintaining structural integrity. The local environment within the gas diffusion layer provides mechanical support that prevents agglomeration even at high metal loadings.

Inventive Principle:

Principle #3Local quality

3Reliability

If a microporous layer is added between GDL and catalyst layer to prevent catalyst particle penetration, then particle retention improves, but the overall structure complexity increases

Engineering Contradiction:

Improveprevention of catalyst particle penetrationVSAvoidnumber of layers in electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the microporous layer by integrating the catalytic function directly into the gas diffusion layer. The gas diffusion layer itself is designed with appropriate porosity and mechanical properties to retain the noble metal particles, removing the need for an additional microporous barrier layer and simplifying the overall electrode structure.

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides a stable and long-term resistant gas diffusion electrode with an extremely large accessible catalytic surface, preventing coalescence and washout of noble metals, thus enhancing the fuel cell's performance and durability.

Implementation Method 1

a gas-permeable substrate which is formed from an organic polymer which has functional groups capable of complexing metal cations

Methodology Applied

Scientific EffectComplexation: Chemical Bonding

Implementation Method 2

Gas diffusion layers (GDL) are arranged on both sides of the electrode

Methodology Applied

Scientific EffectGas diffusion: Diffusion

Data Source

PatentUS11283081B2Gas diffusion electrode and fuel cell comprising such a gas diffusion electrode

Publication Date: 2022.03.22 AUDI AG

AI summary

A gas diffusion electrode for a fuel cell which comprises a gas-permeable substrate that has functional groups is provided, said groups being capable of complexing cations, and catalytically active noble metal particles and/or atoms, said particles and/or atoms being bonded by the functional groups to a surface of a first flat side of the substrate and/or in a surface-proximal region of a first flat side of the substrate. The gas diffusion electrode according to the invention combines the functions of a gas diffusion layer and a catalytic layer in an integral component and is distinguished by a high long-term stability with respect to degradation phenomena of the catalyst.