Electronic structure variation of the surface and bulk of a LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub>cathode as a function of state of charge: X-ray absorption spectroscopic study
Bibliographic record
Abstract
The electronic structure at the Ni, Mn and O sites and their evolution upon the electrochemical lithiation of Li(1-x)Ni0.5Mn1.5O4 (LNMO) in a lithium ion battery has been explored using comprehensive X-ray absorption near edge structure spectroscopy (XANES) at the Ni and Mn L3,2- and O K-edges, with both surface-sensitive and bulk-sensitive detection. It has confirmed that Ni reduction from Ni(4+) to Ni(2+) plays the leading role in charge compensation when the lithiation voltage is above 4.5 V. Our study also unveils the participation of oxygen in the charge compensation. Furthermore, the enhanced difference in the electronic structures of the surface and bulk in electrochemically cycled samples, and the different surface electronic structures of the fully discharged LNMO and the pristine one, highlight the importance of electrochemical activation. These findings are critical for a better understanding of the electrochemical reaction of LNMO and the influence of structural modifications to the surface region upon its performance, and will assist further efforts to improve this high-voltage cathode material for its application in lithium ion batteries.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".