Experimental Observations of Microstructure Changes in the Catalyst Layers of Proton Exchange Membrane Fuel Cells under Wet-Dry Cycles
Bibliographic record
Abstract
Microstructure changes of the catalyst layers in proton exchange membrane fuel cells (PEMFCs) lead to significant performance degradation and durability limitations, especially under dynamic loading condition; and they are investigated experimentally in this study simulating the effect of wet-dry cycles through water intrusion-evaporation and water flow-through-dehydration experiments, respectively. It is found that the cycling of water intrusion-evaporation processes significantly contributes to the growth of agglomerates as well as the formation of pinholes and cracks, causing irreversible losses of active surface areas and catalytic activity; in contrast, the cycling of water flow-through-dehydration experiments enlarges the large pores but changes very little the agglomerate sizes. This is because water tends to flow through the path of least resistance, that is, the large pores in the catalyst layers, leaving the other parts of the catalyst layers with relatively small pores less affected. These observations provide experimental evidence of microstructure changes and their forms for a better understanding of degradation in PEMFCs, especially under dynamic operating conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".