Low Platinum Load Electrode for Fuel Cells

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Solution Overview

Problem

Low platinum load electrodes in proton exchange membrane fuel cells experience high power performance losses due to increased oxygen transport losses and ohmic losses, which are not adequately addressed by simply reducing platinum loading, necessitating a more efficient catalyst layer design.

Innovation Solution

The electrode design incorporates a platinum loading of less than 0.2 mg/cm² with a tailored ionomer-to-carbon ratio between 0.5 and 0.9, and an ionomer equivalent weight between 700 and 1100, along with a metal weight percent of 20-70% platinum, to minimize oxygen transport losses and ohmic penalties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If platinum loading is reduced to lower costs, then manufacturing cost decreases, but power performance losses increase due to higher oxygen transport losses and ohmic losses

Engineering Contradiction:
Improveplatinum loadingVSAvoidpower performance losses
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent changes the ionomer-to-carbon ratio parameter to a specific range (0.4 to 0.8) and controls the ionomer equivalent weight (700-1100) to optimize the balance between oxygen transport and ionic conductivity. This parameter optimization allows the electrode to maintain acceptable performance at reduced platinum loadings of 0.05-0.20 mg Pt/cm², directly resolving the contradiction between cost reduction and performance maintenance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite catalyst layer structure combining carbon support particles, platinum catalysts, and ionomer in specific proportions. The composite material approach with controlled ionomer-to-carbon ratios enables simultaneous achievement of low platinum loading and reduced oxygen transport losses, as the optimized composite structure provides both cost efficiency and performance

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

This configuration results in an efficient low platinum load electrode with reduced oxygen transport losses and acceptable performance, balancing the trade-offs between ionomer and carbon content to enhance fuel cell efficiency.

Implementation Method 1

The carbon support particles support the platinum catalysts

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the ionomer connects the platinum catalysts

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP2729979B1Low platinum load electrode
Publication Date: 2017.12.13 AUDI AG
  • EP2729979B1 patent drawingFigure 1
  • EP2729979B1 patent drawingFigure 2

AI summary

An electrode for an electrochemical cell includes platinum catalysts, carbon support particles and an ionomer. The carbon support particles support the platinum catalysts, and the ionomer connects the platinum catalysts. The electrode has a platinum loading less than about 0.2 mg/cm2 and an ionomer-to-carbon ratio between about 0.5 and about 0.9. A membrane electrode assembly includes a proton exchange membrane, a cathode layer and an anode layer. The cathode layer includes platinum catalysts, carbon support particles for supporting the platinum catalysts and an ionomer connecting the platinum catalysts. The cathode layer has a platinum loading less than about 0.2 mg/cm2 and an ionomer-to-carbon ratio between about 0.5 and about 0.9. The anode layer includes platinum catalysts, carbon support particles for supporting the platinum catalysts and an ionomer connecting the platinum catalysts.