Calendar Aging and Gas Generation in Commercial Graphite/NMC-LMO Lithium-Ion Pouch Cell
Bibliographic record
Abstract
The calendar life of a commercial graphite/NMC-LMO lithium-ion battery is assessed under various storage temperature (35°C and 60°C) and state-of-charge (0% and 100%) conditions. Virtually no degradation is observed for cells stored at 0% SOC as expected, whereas those aged for 9 months in a fully charged state at 35°C and 60°C lose ∼10% and ∼43% of their capacity, respectively. Differential-voltage analysis of periodic cell cycling data and post-mortem examination of the aged electrodes are used to identify degradation modes. Three main sources of high-temperature capacity loss are identified: i) electrode dry-out due to gas formation (∼30%), ii) loss of cyclable lithium (∼10%) and iii) cathode active material loss (∼3%). Cells stored at a lower temperature of 35°C experience little gas generation and degrade primarily through the loss of Li inventory. The analysis shows that similar amounts of cyclable Li are consumed by side reactions during calendar aging at both storage temperatures of 35°C and 60°C. Non-destructive compression (1.0–5.0 psi) of the aged pouch cells during discharge is shown to improve their capacity by ∼15%. This effect is attributed to the redistribution of gas bubbles inside the pouch cell by the applied pressure.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.001 | 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".