In Situ X-Ray Absorption Study of a Layered Manganese-Chromium Oxide-Based Cathode Material
Bibliographic record
Abstract
We have investigated the electronic and atomic structure of a manganese-chromium-based layered oxide material during electrochemical cycling using in situ X-ray absorption spectroscopy. Our results indicate that charge compensation in the cathode material is achieved by the oxidation/reduction of octahedral Cr(III) ions to tetrahedral Cr(VI) ions during delithiation/lithiation. Manganese ions are present predominantly in the Mn(IV) oxidation state and do not appear to actively participate in the charge compensation process. To accommodate the large changes in coordination symmetry of the Cr(III) and Cr(VI) ions, the chromium ions have to move between the regular octahedral sites in the -like lattice to interstitial tetrahedral sites during the charge/discharge process. The highly reversible (at least after the first charge) three-electron oxidation/reductions and the easy mobility of the chromium between octahedral and tetrahedral sites are very unusual and interesting. Equally interesting is the fact that chromium is the active metal undergoing oxidation/reduction rather than manganese. Our results also suggest that in the local scale manganese and chromium ions are not evenly distributed in the as-prepared material, but are present in separate domains of Mn and Cr-rich regions. © 2002 The Electrochemical Society. All rights reserved.
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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 | 0.000 |
| 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".