Effect of Mixtures of Lithium Hexafluorophosphate (LiPF<sub>6</sub>) and Lithium Bis(fluorosulfonyl)imide (LiFSI) as Salts in Li[Ni<sub>1/3</sub>Mn<sub>1/3</sub>Co<sub>1/3</sub>]O<sub>2</sub>/Graphite Pouch Cells
Bibliographic record
Abstract
The effect of mixtures of lithium hexafluorophosphate (LiPF 6 ) and lithium bis(fluorosulfonyl)imide (LiFSI) with different molar ratios in the electrolyte of Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 /graphite pouch cells was studied using the ultra-high precision charger (UHPC) at Dalhousie University, an automated storage system, electrochemical impedance spectroscopy (EIS) and gas evolution measurements. Ethylene carbonate: ethyl methyl carbonate (EC:EMC, 3:7 wt.% ratio) solvent was used as the base solvent in these studies. Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 /graphite pouch cells containing both LiPF 6 and LiFSI (with a total salt content of 1 M) with or without 2% VC showed smaller or similar self-discharge, lower charge transfer resistance (R ct ), and smaller amounts of gas evolution during formation and during storage at high temperature, compared to cells containing only 1 M LiPF 6 with and without 2% VC, respectively. For cells without 2% VC, cells with 0.3 M LiPF 6 + 0.7 M LiFSI showed the smallest self-discharge and the lowest R ct after 40°C storage. For cells with 2% VC, cells with 0.5 M LiPF 6 + 0.5 M LiFSI + 2% VC showed the lowest voltage drop and the lowest R ct after 40°C storage. The UPHC cycling data showed that cells containing LiPF 6 :LiFSI mixtures with 2% VC showed similar coulombic efficiency (CE), and similar charge end-point capacity slippage compared to cells with 1 M LiPF 6 + 2% VC. The combination of LiFSI and LiPF 6 in electrolytes that contain 2% VC can bring benefits of improved storage properties and reduced gas evolution at high temperature while maintaining all other properties of the cells in experiments limited to 4.2 V. However, preliminary experiments at voltages up to 4.45 V suggest that LiFSI may lead to increased transition metal dissolution (Ni, Mn and Co) compared to lithium bistrifluoromethane sulfonyl imide (LiTSFI), another salt additive used to improve storage properties and reduce gassing.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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".