| Autor: |
Herrmann, Niklas J., Euchner, Holger, Groß, Axel, Horstmann, Birger |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
Adv. Energy Mater. 2023, 2302553 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1002/aenm.202302553 |
| Popis: |
Zinc-based batteries offer good volumetric energy densities and are compatible with environmentally friendly aqueous electrolytes. Zinc-ion batteries (ZIBs) rely on a lithium-ion-like Zn$^{2+}$-shuttle, which enables higher roundtrip efficiencies and better cycle life than zinc-air batteries. Manganese-oxide cathodes in near-neutral zinc sulfate electrolytes are the most prominent candidates for ZIBs. Zn$^{2+}$-insertion, H$^+$-insertion, and Mn$^{2+}$-dissolution are proposed to contribute to the charge-storage mechanism. During discharge and charge, two distinct phases are observed. Notably, the pH-driven precipitation of zinc-sulfate-hydroxide is detected during the second discharge phase. However, a complete and consistent understanding of the two-phase mechanism of these ZIBs is still missing. This paper presents a continuum full cell model supported by DFT calculations to investigate the implications of these observations. We integrate the complex-formation reactions of near-neutral aqueous electrolytes into the battery model and, in combination with the DFT calculations, draw a consistent picture of the cycling mechanism. We investigate the interplay between electrolyte pH and reaction mechanisms at the manganese-oxide cathodes and identify the dominant charge-storage mechanism. Our model is validated with electrochemical cycling data, cyclic voltammograms, and in-situ pH measurments. This allows us to analyse the influence of cell design and electrolyte composition on cycling and optimize the battery performance. |
| Databáze: |
arXiv |
| Externí odkaz: |
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