A Study of the Reactivity of De-Intercalated P2-Na<sub>x</sub>CoO<sub>2</sub>with Non-Aqueous Solvent and Electrolyte by Accelerating Rate Calorimetry
Bibliographic record
Abstract
P2-type layered structure Na x CoO 2 (x∼0.65) was successfully synthesized by solid state reaction. The electrochemical performance of Na 0.65 CoO 2 as a positive electrode material for sodium-ion batteries was tested at room temperature using two-electrode coin cells with NaClO 4 /PC electrolyte. Na 0.65 CoO 2 delivered a reversible capacity of 70 mAh/g during the first charge to 4.3 V, which is related to the de-intercalation of about 0.3 mol Na per mole Co. The reactivity of de-intercalated Na x CoO 2 (∼Na 0.35 CoO 2 ) with ethylene carbonate/diethyl carbonate (EC:DEC) solvent and with NaPF 6 /EC:DEC electrolyte was studied using Accelerating Rate Calorimetry (ARC). X-ray diffraction was used to study the products of the reactions of Na 0.35 CoO 2 with solvent or electrolyte after the ARC experiments. De-intercalated Na x CoO 2 shows high reactivity in both solvent and electrolyte. Na 0.35 CoO 2 reacts with solvent at elevated temperature in a manner which is similar to de-intercalated Li x CoO 2 , leading to the products Na 0.7 CoO 2 and Co 3 O 4 . Then Na 0.7 CoO 2 reacts to form Co 3 O 4 and NaHCO 3 . Then Co 3 O 4 reacts to form CoO or Co metal. In NaPF 6 -based electrolyte, the reaction mechanism changes completely as the major reaction products are NaCoF 3 and CoO or Co.
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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 | 0.001 |
| 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 | 0.001 |
| 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".