Fuel Cell Poison-Scrubbing Catalyst Layer Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell systems face challenges with electrocatalyst poisoning and cell voltage reversal, as well as catalyst crossover, which affect performance and durability, especially in dynamic and varying operating conditions.
Innovation Solution
A fuel cell system design featuring a membrane electrode assembly with an electrochemically separating sublayer between the proton exchange membrane and the anode substrate, incorporating a poison-scrubbing catalyst layer that includes platinum, ruthenium, and other metals, supported on catalyst supports like carbon or metal oxides, to prevent catalyst crossover and enhance tolerance to poisoning species and voltage reversals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a poison-scrubbing catalyst layer is disposed beside the electrocatalyst layer to reduce electrocatalyst poisoning, then fuel cell robustness to poisoning species is improved, but fuel cell performance and durability degrade over time
Solution Approach 1:
An electrochemically separating sublayer is introduced as an intermediary between the poison-scrubbing catalyst layer and the electrocatalyst layer. This sublayer prevents direct contact between the catalyst layer and electrocatalyst, eliminating the harmful interaction that causes performance degradation while allowing the catalyst layer to continue scrubbing poisoning species from the fuel stream.
Solution Approach 2:
The anode structure is segmented into distinct functional layers: the poison-scrubbing catalyst layer is separated from the electrocatalyst layer by the electrochemically separating sublayer. This segmentation allows each layer to perform its specific function independently - the catalyst layer for poison removal and the electrocatalyst layer for electrochemical reactions - without mutual interference.
2Reliability
If a carbon monoxide filter layer is disposed beside the flow field plate to reduce poisoning, then initial fuel cell robustness is improved, but tolerance to poisoning decreases over time
Solution Approach 1:
The electrochemically separating sublayer acts as a mediator that prevents the catalyst layer from interacting with the electrocatalyst. By positioning this sublayer between the catalyst layer and the electrocatalyst, the system maintains poison-tolerant performance over time without the degradation observed in conventional designs where the catalyst layer is directly adjacent to the electrocatalyst.
3Reliability
If Pt-Ru bimetallic catalyst is used to reduce carbon monoxide poisoning effect, then fuel cell robustness to poisoning is improved, but catalyst crossover increases
Solution Approach 1:
The electrochemically separating sublayer serves as a barrier that prevents Pt-Ru catalyst particles from crossing over to the cathode side. This sublayer allows the Pt-Ru catalyst to maintain its poison-scrubbing function while eliminating the harmful catalyst crossover effect that would otherwise occur with this bimetallic catalyst system.
Solution Approach 2:
The harmful function of the Pt-Ru catalyst (catalyst crossover) is extracted and eliminated by the electrochemically separating sublayer, while the useful function (carbon monoxide poisoning resistance) is preserved. The sublayer selectively removes the harmful crossover effect while allowing the catalyst to continue its intended poison-scrubbing role.
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 effectively reduces the impact of poisoning species like carbon monoxide and improves tolerance to cell voltage reversals by preventing catalyst crossover and maintaining fuel cell performance and durability.
Implementation Method 1
a poison-scrubbing catalyst layer disposed between the electrochemically separating sublayer and the anode substrate
Implementation Method 2
the use of a bimetallic anode electrocatalyst comprising platinum/ruthenium, rather than monometallic platinum, shows a reduction in the poisoning effect of carbon monoxide
Implementation Method 3
an electrochemically separating sublayer disposed between the proton exchange membrane and the anode substrate
Implementation Method 4
Fuel cells convert fuel and oxidant to electricity and reaction product
Implementation Method 5
At the anode, fuel, typically in the form of hydrogen gas, reacts at the electrocatalyst in the presence of the PEM to form hydrogen ions and electrons
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A membrane electrode assembly (MEA) may include an electrochemically separating sublayer disposed between the proton exchange membrane and an anode substrate. The MEA may also include a poison-scrubbing catalyst disposed between the electrochemically separating sublayer and the anode substrate. An anode electrocatalyst disposed between the proton exchange membrane and the electrochemically separating sublayer and a cathode electrocatalyst disposed between the cathode substrate and the proton exchange membrane.