Oxygen Redox Activity in Cathodes – a Common Phenomenon Calling for Density-Based Descriptors
Bibliographic record
Abstract
Lithium-excess transition metal oxide materials are promising cathode candidates for future secondary batteries due to their relatively high energy density, which is commonly related to redox-active oxygen centers. First-principle computations are crucial for the understanding of the underlying redox mechanism in these compounds, with plane-wave density functional theory being the most frequently used setup. An important tool for the assignment of the redox-active species is the projected density of states, although the atomic contributions postulated this way do not strictly correspond to any observable physical quantity. By directly analyzing the computed real-space charge density changes, on the other hand, oxygen redox activity can be found to be substantial in most transition metal oxide compounds, although a projection onto atomic states would suggest otherwise. This can be linked to the shortcomings of the commonly employed spherical approximation for ions in crystalline compounds used to compute the projected density of states, which fails to describe the charge density topology in covalent transition metal oxides and leads to a qualitatively different picture from a charge density-based approach, specifically, the underrepresentation of oxygen contributions and exaggeration of transition metal contributions to the density of states The density based approach, due to the non-spherical nature of Bader domains, is more apt to properly describe oxygen redox contributions. This raises the question how meaningful the descriptors of oxygen redox activity are and how it should be acknowledged for transition metal oxide compounds in general.
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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".