Ammonium Bifluoride‐Etched MXene Modified Electrode for the All−Vanadium Redox Flow Battery
Bibliographic record
Abstract
Abstract The development of electrodes with high performance and long‐term stability is crucial for commercial application of vanadium redox flow batteries (VRFBs). This study compared the performance of VRFB with thermal‐treated and MXene‐modified carbon paper. To prepare the MXene, a modified‐etching process with ammonium−bifluoride (NH 4 HF 2 ) led to a mild and efficient conversion of the MAX‐phase to MXene compared to etching process with hydrofluoric‐acid (HF). Electron microscopy and X‐ray diffraction studies revealed that the etching process with NH 4 HF 2 led to MXene nanostructures with a large interlayer spacing. The results show that at a current density of 60 mA cm −2 , the energy efficiency increased by 25.5 % when using a NH 4 HF 2 ‐etched MXene‐modified negative electrode, by 12.5 % with a thermal‐treated MXene‐modified electrode, and by 4 % with an HF‐etched MXene‐modified electrode, in comparison to the pristine electrode. The maximum power density of the battery was increased by more than 40 %. In long‐term cycling experiments the MXene modified electrode exhibited excellent stability over 1000 cycles of charge‐discharge, with 0.05 % discharge capacity decay per cycle, amongst the lowest values reported to date and four times lower than for thermally‐treated electrode. The superior performance was linked to the improved electrical conductivity and wettability, higher interlayer spacing, and lower charge transfer resistance for the V 2+ /V 3+ redox reaction.
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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 | 0.001 | 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".