Porous Ceramic Catalyst Layer for PEFC Water Management
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Solution Overview
Problem
Polymer electrode fuel cells (PEFCs) face challenges with carbon carrier corrosion and noble metal catalyst dissolution, leading to catalyst layer deterioration and flooding phenomena due to inadequate water management, which affects cell voltage and endurance, especially in automotive applications.
Innovation Solution
A catalyst layer comprising two or more noble metal-containing layers separated by porous ceramic layers with voids, which improves water management and reduces the amount of noble metal required, enhancing both endurance and robustness by allowing for efficient water absorption and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon carrier is used in catalyst layer, then catalyst loading is feasible, but carbon carrier corrodes and catalyst dissolves during repeated operations
Solution Approach 1:
The patent extracts the carbon carrier from the catalyst layer structure and replaces it with a porous substrate. The catalyst is directly formed on the porous substrate through sputtering or vapor deposition, eliminating the carbon carrier that causes corrosion and catalyst dissolution during repeated operations.
Solution Approach 2:
The patent uses a composite structure combining a porous substrate with noble metal catalyst layers. The porous substrate provides mechanical support and water management functionality, while the noble metal layers provide catalytic activity, creating a durable composite catalyst layer without carbon carrier.
2Reliability
If sputtering or vapor-deposition is used to form catalyst layer without carbon carrier, then endurance is sufficient, but flooding phenomenon occurs and water management is inadequate
Solution Approach 1:
The patent employs a porous substrate with controlled pore structure to enable effective water management. The porosity allows water produced by electrode reaction to be drained efficiently, preventing flooding phenomenon while maintaining sufficient endurance through the durable noble metal catalyst layers.
Solution Approach 2:
The patent creates different functional zones within the catalyst layer: the porous substrate provides water drainage pathways, while the noble metal-containing layers provide catalytic sites. This local differentiation of properties enables both excellent water management and sufficient endurance simultaneously.
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 catalyst layer design achieves high cell voltage, excellent robustness, and sufficient endurance by managing water effectively and minimizing noble metal usage, preventing corrosion and flooding, thus improving the performance and longevity of PEFCs.
Implementation Method 1
a porous ceramic layer 23 which is placed between the noble metal-containing layers 22 and contains voids 23a
Implementation Method 2
a catalyst layer 14 comprising two or more noble metal-containing layers 22
Data Source
AI summary
Embodiments of the present disclosure aim to provide a catalyst layer ensuring a high cell voltage and having both excellent robustness and sufficient endurance, and also to provide a process for producing the layer, a membrane electrode assembly and an electrochemical cell. The catalyst layer comprises two or more noble metal-containing layers, and a porous ceramic layer placed between the noble metal-containing layers. Further, in the catalyst layer, voids exist between the porous ceramic layer and the noble metal-containing layers.