Degradation of Carbon Electrodes in the All‐Vanadium Redox Flow Battery
Bibliographic record
Abstract
Abstract The charge−discharge operation of the vanadium redox flow battery degrades the electrodes over time and results in a performance and efficiency decay. The impact of extended charge−discharge cycling operation on carbon electrodes is investigated using carbon paper as a model electrode. Electrode degradation along with 70 % degradation of charge−discharge capacity was observed after 100 charge−discharge cycles of a single cell vanadium redox flow battery operating at a current density of 80 mA cm −2 at room temperature (23 °C). Raman mapping of the electrodes shows a decrease in structural defects in the negative electrode, and an increase in defects in the positive electrode, indicating differences in the degradation mechanism at each electrode. Electrochemical investigation reveals an increase in the activation overpotential at both the positive and negative electrodes. However, the negative electrode showed a higher activation overpotential indicating a higher impact of electrode degradation on the negative side. X‐ray photoelectron spectroscopy shows around an eightfold increase in surface oxygen functional groups after degradation in both positive and negative electrodes. The composition of oxygen functional groups was also observed to change significantly after degradation from dominantly carbonyl‐based to a combination of carbonyl‐ and carboxyl‐based groups. This study provides insight into the electrode degradation mechanism and highlights the differences in the mechanism for the positive and negative electrodes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| 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 | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".