Layered Lithium Vanadium Fluorophosphate, Li<sub>5</sub>V(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>: A 4 V Class Positive Electrode Material for Lithium-Ion Batteries
Bibliographic record
Abstract
A single-phase, well-crystallized Li 5 V(PO 4 ) 2 F 2 /carbon nanocomposite has been prepared by an optimized solid-state route, and its electrochemical behavior was examined as a positive electrode active material in lithium-ion batteries. The microcrystalline powder was synthesized by the reaction of amorphous VPO 4 /C with Li 3 PO 4 and LiF. Synthesis of the VPO 4 /C precursor utilized carbon to reduce V 2 O 5 and simultaneously create a nanoparticle reactive material, with the amount being tailored to result in a small excess at the end of the reaction to increase the bulk electronic conductivity of the final Li 5 V(PO 4 ) 2 F 2 composite. Quench techniques were used to isolate the metastable two-dimensional Li 5 V(PO 4 ) 2 F 2 as a pure single phase. 6 Li MAS NMR studies identified the crystallographic lithium sites and provided information on lithium-ion mobility and exchange in the two-dimensional layered structure. Lithium cells of the Li 5 V(PO 4 ) 2 F 2 /C composite exhibited a reversible plateau at 4.15 V followed by a second plateau at 4.65 V, which correspond to the V 3+ /V 4+ and V 4+ /V 5+ redox couples, respectively, and a charge capacity of 165 mA h g −1, which is close to theoretical (170 mA h g −1 ). These operating voltages are very similar to those of the V 3+ /V 4+ couple in Li 3 V 2 (PO 4 ) 3 or LiVPO 4 F and the V 4+ /V 5+ couple in Li 3 V 2 (PO 4 ) 3 .
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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 | 0.001 | 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".