Reaction mechanisms for electrolytic manganese dioxide in rechargeable aqueous zinc-ion batteries
Bibliographic record
Abstract
Abstract This study reports the phase transformation behaviour associated with electrolytic manganese dioxide (EMD) utilized as the positive electrode active material for aqueous zinc-ion batteries. Electrochemical techniques, including galvanostatic charge–discharge and rotating ring-disk electrode measurements, and microstructural techniques, using X-ray powder diffraction, scanning electron microscopy, and transmission/scanning transmission electron microscopy, were utilized to characterize the positive electrode at different stages of discharge and charge of zinc-ion cells. The results indicate that, during discharge, a fraction of EMD undergoes a transformation to ZnMn 2 O 4 (spinel-type) and Zn 2+ is intercalated into the tunnels of the γ- and ε-MnO 2 phases, forming Zn x MnO 2 (tunnel-type). When a critical concentration of Mn 3+ in the intercalated Zn x MnO 2 species is reached, a disproportionation/dissolution reaction is triggered leading to the formation of soluble Mn 2+ and hydroxide (OH – ) ions; the latter precipitates as zinc hydroxide sulfate (ZHS, Zn 4 (OH) 6 (SO 4 )·5H 2 O) by combination with the ZnSO 4 /H 2 O electrolyte. During charge, Zn 2+ is reversibly deintercalated from the intergrown tunneled phases (γ-/ε-Zn x MnO 2 ), Mn 2+ is redeposited as layered chalcophanite (ZnMn 3 O 7 ·3H 2 O), and ZHS is decomposed by protons (H + ) formed during the electrochemical deposition of chalcophanite.
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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".