Iridium-Ruthenium Bipolar Plate Layers for Oxidation-Stable Conductivity
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Solution Overview
Problem
Bipolar plates in fuel cells and electrolyzers face challenges such as brittleness, high surface resistance, corrosion, and high production costs, particularly due to the instability of gold coatings and the formation of oxidic metal complexes with hard material layers like titanium nitride, which lead to anodic dissolution and increased resistance.
Innovation Solution
A layer system comprising a homogeneous or heterogeneous solid metallic solution or compound with iridium and ruthenium noble metals, combined with nonmetallic elements like carbon, nitrogen, boron, fluorine, and hydrogen, providing improved conductivity, corrosion resistance, and stability, with a thickness of 1-10 nm, and a base layer system that includes refractory metals to enhance durability and reduce noble metal usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon plates are used for bipolar plates, then electrical conductivity is achieved, but brittleness and thickness increase reducing performance volume
Solution Approach 1:
The patent applies composite materials by combining carbon plates with metallic bipolar plates to create a hybrid structure that leverages the electrical conductivity of carbon while utilizing the mechanical strength and ductility of metals, thereby resolving the contradiction between achieving conductivity and avoiding brittleness
2Reliability
If carbon plates are used for bipolar plates, then electrical conductivity is achieved, but plate thickness increases reducing performance volume
Solution Approach 1:
The composite structure allows for thinner plate designs by combining materials with complementary properties, achieving the required electrical conductivity with reduced thickness compared to pure carbon plates, thus increasing performance volume
3Length of stationary object
If austenitic stainless steel is used for bipolar plates, then plate thickness is reduced, but surface oxides form increasing surface resistance
Solution Approach 1:
The patent combines austenitic stainless steel with carbon materials to create a composite bipolar plate where the carbon component provides oxidation resistance, preventing surface oxide formation on the steel while maintaining the thin plate geometry and low surface resistance
4Length of stationary object
If austenitic stainless steel is used for bipolar plates, then plate thickness is reduced, but corrosion resistance decreases
Solution Approach 1:
The composite structure combines austenitic stainless steel with carbon materials that provide superior corrosion resistance, creating a bipolar plate that maintains thin geometry while achieving enhanced protection against corrosive environments through the synergistic properties of both materials
5Reliability
If gold coating is applied to austenitic steel, then corrosion resistance is improved, but cost increases and dissolution occurs under unfavorable conditions
Solution Approach 1:
The patent replaces expensive gold coating with a composite structure combining austenitic stainless steel and carbon materials, achieving comparable or superior corrosion resistance without the high costs and dissolution issues associated with gold, particularly in chloride-containing environments
Solution Approach 2:
The composite material approach uses cost-effective austenitic stainless steel as the base material, eliminating the need for expensive noble metal coatings while maintaining adequate service life through the corrosion-resistant composite structure
6Strength
If titanium nitride coating is applied, then hardness is improved, but oxidic metal complexes form increasing surface resistance
Solution Approach 1:
The patent combines titanium nitride coating with carbon-containing materials to create a composite coating structure where the carbon component prevents oxidation of the titanium nitride, maintaining low surface resistance while preserving the hardness and mechanical strength benefits of the titanium nitride layer
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 layer system achieves high oxidation stability above 2000 mV, low electrical resistance, and self-healing properties, significantly extending the life of fuel cells and electrolyzers by preventing corrosion and maintaining conductivity, with a reduced need for expensive noble metals.
Implementation Method 1
The layer system achieves high oxidation stability above 2000 mV
Implementation Method 2
preventing corrosion and maintaining conductivity
Implementation Method 3
providing improved conductivity, corrosion resistance, and stability, with a thickness of 1-10 nm
Implementation Method 4
achieves high oxidation stability above 2000 mV, low electrical resistance, and self-healing properties
Data Source
AI summary
Layers for a bipolar plates are disclosed, as well as bipolar plates including the layers and fuel cells and/or electrolyzers including the bipolar plates. The layer may include a homogeneous or heterogeneous solid metallic solution or compound which either contains a first chemical element from the group of the noble metals in the form of iridium; or contains a first chemical element from the group of the noble metals in the form of iridium and a second chemical element from the group of the noble metals in the form of ruthenium. The layer may also include at least one further nonmetallic chemical element from the group consisting of nitrogen, carbon, boron, fluorine, and hydrogen.