Development of a LiMnFePO<sub>4 </sub>/ Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> 2Ah Pouch Cell: An Example of the Effective Integration of New Materials
Bibliographic record
Abstract
One of the most promising approaches for limiting climate change is the use of alternative and greener sources of energy (wind, solar, etc.). The electricity generated from these sources fluctuates, however, and a storage solution is needed. The advent of energy storage for wind farms, solar plants, etc., requires a new generation of batteries. It is therefore imperative that a battery with high energy density, a longer life cycle and improved safety be developed. In this paper, we describe our efforts to develop a safe and long-life cycle LiMnFePO4 (LMFP)/Li4Ti5O12 (LTO) 2Ah pouch cell. One of the major challenges faced in this pursuit was gas evolution during cycling. Various side reactions with active materials resulted in the generation of gas during cycling. To circumvent this, we implemented several mitigation strategies. To combat electrolyte degradation (1.0 M LiPF6 in carbonate solvents) due to Mn2+ dissolution in LMFP, we integrated a new class of polymer as a binder in the cathode preparation, which effectively decreased the degradation during cycling. This polymer also has high voltage stability.1 At the battery’s negative electrode, we developed a new carbon coating method on LTO that minimizes electrolyte degradation and optimizes high C-rate preformances, especially fast charging performances.2 Although these new materials reduce gas evolution, they do not eliminate it. Therefore, we developed the first polymer capable of trapping the carbon dioxide, major component of gases generated during cycling and, in turn, preventing pouch cell inflation. This polymer was integrated in a pouch cell in the form of an insoluble trapping sheet.3 Although relatively simple, this technology made the pouch cells safer. This unique approach is versatile and can be implemented in pouch cells with any type of chemistry when gas scavenging is required. The 2Ah pouch cells did not experience any inflation during extensive cycling and aging. Cells cycled more then 750 cycles at 45oC with a rate of 1C – 1C before reaching 80% retention capacity. Reference (1) Daigle, J.-C.; Asakawa, Y.; Zaghib, K. Polymer additives and their use in electrode materials and electrochemical cells. WO2020061710A1, 2020. (2) Daigle, J.-C.; Asakawa, Y.; Beaupre, M.; Gariepy, V.; Vieillette, R.; Laul, D.; Trudeau, M.; Zaghib, K. Boosting Ultra-Fast Charge Battery Performance: Filling Porous nanoLi4Ti5O12 Particles with 3D Network of N-doped Carbons. Sci. Rep. 2019, 9 (1), 1-9, DOI: 10.1038/s41598-019-53195-1. (3) Daigle, J.-C.; Asakawa, Y.; Perea, A.; Dontigny, M.; Zaghib, K. Novel polymer coating for chemically absorbing CO2 for safe Li-ion battery. Sci. Rep. 2020, 10 (1), 10305, DOI: 10.1038/s41598-020-67123-1.
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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 | 0.000 |
| 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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".