Mechanism of the Fe<sup>3+</sup> Reduction at Low Temperature for LiFePO<sub>4</sub> Synthesis from a Polymeric Additive
Bibliographic record
Abstract
Comparison is made between the use of either a carbon powder or a polymer additive to the precursors in the synthesis of LiFePO 4 from the Fe(III) compound FePO 4 (H 2 O) 2 and Li 2 CO 3 . The evolution of the structural properties and phase purity with temperature and time have been monitored at all length scales by X-ray diffraction, Fourier transformed infrared spectroscopy, and magnetic susceptibility. The reactor temperature was decreased to 300 °C to investigate the early stages of the reaction. Formation of crystalline LiFePO 4 begins in the range 300−400 °C only if the polymer is used as the carbonaceous additive. This LiFePO 4 formation is made possible by the reduction of Fe(III) species by gases such as H 2 or gaseous hydrocarbons evolved during the calcination of the polymer. Moreover, decomposition of the polymer results in a carbonaceous deposit on the surface of the LiFePO 4 particles. An Li 3 Fe 2 (PO 4 ) 3 impurity found after sintering at 400 °C for 4 h was greatly reduced after sintering at 400 °C for 24 h, and phase-pure LiFePO 4 was attained at 700 °C. Where the solid carbon powder was used as the reducing agent, no Fe(II) species could be detected after sintering at 400 °C. Carbothermal reduction of Fe(III) is ruled out in this temperature range.
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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) | 0.000 | 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) | 0.000 | 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".