Electron Transfer and Transport Properties of Redox Compounds in Highly Concentrated Electrolytes
Bibliographic record
Abstract
Highly concentrated electrolytes (HCE) are currently gaining the interest of the scientific community for battery applications. These electrolytes are obtained when the number of ions of a salt nears or equals that of the solvent molecules, while maintaining a liquid state. In such systems, the solvent molecules are all found as complexes with the cations, usually Li+. It is currently accepted that in HCE, no “free” molecules of solvent are found in the solution since they are entirely located in the sphere of solvation of the ions present in large quantities. This unique structure brings a greater electrochemical stability of the solvent and a higher Li+ transport number. These properties have stimulated research to apply HCE in several electrochemical systems. For instance, HCEs employing acetonitrile as the solvent have been applied in lithium metal batteries while acetonitrile with moderate salt concentration spontaneously decomposes on lithium. Despite the attractiveness of these electrolytes, the origin of the properties and the relationships between the structure and those properties are still poorly understood, and there is currently no study on heterogeneous electron transfer in such electrolyte. We therefore aim at determining if the HCE structure has an impact on electron transfert. The approach developed in our group is the study of HCE based on LiTFSI and acetonitrile, a well-studied system quite representative of the highly concentrated systems. The approach that will be presented is divided in two parts. The first part concerns the study of the physicochemical properties of HCE. This strategy highlights the factors that have a significant impact on the properties of electrolytes. One of these factors is the water content. The results demonstrate that the presence of water in the solutions has a limited impact on the physical properties of viscosity and density of the mixtures as long as the concentration remains at or below 1000 ppm. The water content has also an impact on the electrochemical stability window (ESW). The ESW of HCE, decreases from 5.45V to less than 2.5 V at 1000 ppm of water. The second part concerns the study of the electron transfer rate of redox couples in HCE. We investigated the solvating structure of highly concentrated electrolytes via the electrochemistry of redox molecules. The first redox couple is the Ferrocenium/Ferrocene (Fc+/Fc) to probe the impact of the electrolyte properties on electron transfer reactions and to validate the approaches used. In the highly concentrated system, the Fc+/Fc redox couple follows the same relation (Stokes-Einstein and Nicholson-Shain) as the ideally dilute system. Two others redox couple have been studied, the Ru(bpy)3 3+/2+ and Fe3+/2+, to investigate the effect of different charges and electron transfer mechanisms. The inner sphere electron transfer of the Fe3+/2 redox couple is more affected by the salt concentration than the outer sphere complex (Ru(bpy)3 3+/2+ and Fc). These results highlight the importance of structure and composition in the development of highly concentrated electrolytes.
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 | 0.000 |
| 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 | 0.000 |
| 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".