Progress towards new materials for proton exchange membranes (PEM)s in fuel cells (FCs)
Bibliographic record
Abstract
Proton exchange membrane (PEM) fuel cells (FC)s are electrochemical devices that convert the chemical energy of a fuel directly and efficiently into electrical and thermal energy. The presently used Nafion type perfluorosulfonic acid polymers have some excellent properties along with a few shortcomings. One of the most serious disadvantages preventing widespread use of FCs is the high cost of the material. Another is the unacceptable methanol permability in the direct methanol FC application. We have been investigating several aspects of FC materials. The first aspect is an investigation of the polymer-solvent interactions that occur during film preparation. During PEM preparation from sulfonated polymer, thin uniform films are usually prepared by casting the polymer solutions from solvents. The literature reports large variations in the proton conductivities of similarly sulfonated polymers, depending on how the PEM was prepared. We have observed that chemical interactions with the various solvents used in the process of PEM preparation may be one of the reasons for the large discrepancies in proton conductivity data existing in the literature. The second aspect is the development of new materials based on cheaper polyarylethers, which are known for their excellent chemical and thermo-oxidative stability. Proton conductivity is introduced into these materials via the incorporation of sulfonic groups, either by post-sulfonation or by direct copolymerization of sulfonated monomers. The sulfonated polymers investigated to date include poly(ether ether ketone) (PEEK), and new classes of polyarylethers containing naphtalene groups (PAEK-NA) and phtalazinones (PPEK). The polyphthalazinones are soluble, thermally stable polymers with very high T2s.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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 source (direct Gemma or distilled Codex), 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".