High-Energy and Stable Subfreezing Aqueous Zn-MnO2 Batteries with Selective and Pseudocapacitive Zn-Ion Insertion in MnO2
© 2022 Wiley-VCH GmbH.
| Veröffentlicht in: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 34(2022), 21 vom: 25. Mai, Seite e2201510 |
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| Weitere Verfasser: | , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2022
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| Zugriff auf das übergeordnete Werk: | Advanced materials (Deerfield Beach, Fla.) |
| Schlagworte: | Journal Article Zn-MnO2 batteries pseudocapacitive selective Zn2+ insertion subfreezing aqueous batteries |
| Zusammenfassung: | © 2022 Wiley-VCH GmbH. One major challenge of aqueous Zn-MnO2 batteries for practical applications is their unacceptable performance below freezing temperatures. Here the use of simple Zn(ClO4 )2 aqueous electrolytes is described for all-weather Zn-MnO2 batteries even down to -60 °C. The symmetric, bulky ClO4 - anion effectively disrupts hydrogen bonds between water molecules and provides intrinsic ion diffusion even while frozen, and enables ≈260 mAh g-1 on MnO2 cathodes at -30 °C . It is identified that subfreezing cycling shifts the reaction mechanism on the MnO2 cathode from unstable H+ insertion to predominantly pseudocapacitive Zn2+ insertion, which converts MnO2 nanofibers into complicated zincated MnOx that are largely disordered and appeared as crumpled paper sheets. The Zn2+ insertion at -30 °C is faster and much more stable than at 20 °C, and delivers ≈80% capacity retention for 1000 cycles without Mn2+ additives. In addition, simple Zn(ClO4 )2 electrolyte also enables a nearly fully reversible and dendrite-free Zn anode at -30 °C with ≈98% Coulombic efficiency. Zn-MnO2 prototypes with an experimentally verified unit energy density of 148 Wh kg-1 at a negative-to-positive ratio of 1.5 and an electrolyte-to-capacity ratio of 2.0 are further demonstrated |
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| Beschreibung: | Date Revised 26.05.2022 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202201510 |