Electrochemical Performance of Layered Honeycomb Na<sub>2</sub>(Ni<sub>2–<i>x</i></sub>Co<sub><i>x</i></sub>)TeO<sub>6</sub> (<i>x</i> = 0, 0.10, 0.25) Oxides as Sodium-Ion Battery Cathodes
Bibliographic record
Abstract
To develop economically and environmentally viable sodium-based solid-state batteries, we investigated Na 2 (Ni 2– x Co x )TeO 6 ( x = 0, 0.10, 0.25). After synthesizing phase-pure compositions, we confirmed P 6 3 / mcm space group and P2 coordination through high-resolution synchrotron diffraction data, where Na + occupies three different crystallographic positions in the unit cell: Na1, Na2, and Na3. With the incorporation of cobalt into the nickel lattice, an increase in the cell volume is seen. Bond parameters show that the average Ni–Ni distance increases as a result, but the local structure and coordination do not show marked differences. Our density functional theory calculations revealed that sodium at the Na1 site is energetically more favorable and that Co doping increased the lattice constants, supported by our X-ray diffraction data. Electrochemical measurements performed on half-cells versus sodium metal using CR2032-type coin cells revealed exceptionally high specific capacity matching the theoretical value and retained around 120 mAhg –1 at the smallest but optimum concentration of cobalt. The kinetics of storage mechanisms in these compositions reflect pseudo-capacitive behavior. Our results indicate that substitution pathways in the layered oxide family of Na 2 Ni 2 TeO 6 offer the potential for the development of Na-based cathodes with enhanced cycling stability and ionic conductivity.
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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".