Toward the Understanding of the Reaction Mechanism of Zn/MnO2 Batteries Using Non-alkaline Aqueous Electrolytes
Zn/MnO2 systems using non-alkaline aqueous electrolytes have attracted tremendous interest as rechargeable aqueous Zn ion batteries due to their safety and high specific capacities. Despite their promising electrochemical performance, however, their reaction mechanism has remained elusive. Here in this paper, we examined the structural evolution of cryptomelane α-MnO2 cathode by ex situ transmission electron microscopy after electrochemical testing using two different non-alkaline aqueous Zn electrolytes with acetate and triflate salts of different pH values. We have discovered that the systems tested in both electrolytes exhibit a dissolution–deposition reaction mechanism through dissolution–deposition of Mn2+ ions from/on the cathodes with a display of similar discharge/charge product formation. We have also found that the cell tested using the acetate electrolyte shows evidence of structural irreversibility that might contribute to its rapid capacity degradation. This finding offers an important insight into optimizing the cathode design for enhanced electrochemical function of aqueous Zn/MnO2 batteries.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1827709
- Report Number(s):
- BNL--222309-2021-JAAM
- Journal Information:
- Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 18 Vol. 33; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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