| Title: |
Revealing Redox Pathways and Structural Evolution in Cation-Disordered Li 2 MnO 2 F via Operando X‑ray Absorption Spectroscopy |
| Authors: |
Mathieu Cogniard; Yohan Biecher; Davide Salusso; Adrien Boulineau; Jean-François Colin |
| Publication Year: |
2025 |
| Collection: |
Torrens University Australia: Figshare |
| Subject Terms: |
Biochemistry; Medicine; Neuroscience; Physiology; Evolutionary Biology; Sociology; Computational Biology; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; Physical Sciences not elsewhere classified; ray absorption spectroscopy; potential low cost; ex situ x; revealing redox pathways; high energy density; detail redox processes; aged materials highlights; 2 + |
| Description: |
Cation-disordered rocksalt lithium-rich compounds are promising materials for lithium-ion batteries as positive electrodes due to their potential low cost and high energy density. In this paper, we studied in detail redox processes of the composition Li 2 MnO 2 F using a combination of operando and ex situ X-ray absorption spectroscopy. Oxygen redox and manganese redox were deconvoluted during the first cycle by using a chemometric approach. We show a stepwise redox during charge with most of the manganese oxidized before 4.3 V, followed mainly by oxygen redox. In discharge, most of the reduction of Mn 4+ occurs at high voltage above 4.3 V, but a non-negligible amount of Mn 3+ is reduced to Mn 2+ below 2 V, while oxygen redox occurs near 3 V with a strong hysteresis. The local order of the material is characterized by a strong Jahn–Teller deformation that disappears with the oxidation of Mn 3+ . The analysis of aged materials highlights that the capacity fade in the cathode material occurs in two stages: during the first few cycles, due to a decrease in oxygen redox activity and subsequently, due to a reduced manganese redox activity, linked with manganese reduction, O-loss, and probable cation-densification. |
| Document Type: |
article in journal/newspaper |
| Language: |
unknown |
| Relation: |
https://figshare.com/articles/journal_contribution/Revealing_Redox_Pathways_and_Structural_Evolution_in_Cation-Disordered_Li_sub_2_sub_MnO_sub_2_sub_F_via_Operando_X_ray_Absorption_Spectroscopy/29578521 |
| DOI: |
10.1021/acs.chemmater.5c00640.s001 |
| Availability: |
https://doi.org/10.1021/acs.chemmater.5c00640.s001 |
| Rights: |
CC BY-NC 4.0 |
| Accession Number: |
edsbas.8046CF9F |
| Database: |
BASE |