Rescue of dead MnO2 for stable electrolytic Zn-Mn redox-flow battery: a metric of mediated and catalytic kinetics.
Natl Sci Rev
; 11(8): nwae230, 2024 Aug.
Article
em En
| MEDLINE
| ID: mdl-39131921
ABSTRACT
The virtues of electrolytic MnO2 aqueous batteries are high theoretical energy density, affordability and safety. However, the continuous dead MnO2 and unstable Mn2+/MnO2 electrolysis pose challenges to the practical output energy and lifespan. Herein, we demonstrate bifunctional cationic redox mediation and catalysis kinetics metrics to rescue dead MnO2 and construct a stable and fast electrolytic Zn-Mn redox-flow battery (eZMRFB). Spectroscopic characterizations and electrochemical evaluation reveal the superior mediation kinetics of a cationic Fe2+ redox mediator compared with the anionic ones (e.g. I- and Br-), thus eliminating dead MnO2 effectively. With intensified oxygen vacancies, density functional theory simulations of the reaction pathways further verify the concomitant Fe-catalysed Mn2+/MnO2 electrolysis kinetics via charge delocalization and activated O 2p electron states, boosting its rate capability. As a result, the elaborated eZMRFB achieves a coulombic efficiency of nearly 100%, ultra-high areal capacity of 80 mAh cm-2, rate capability of 20 C and a long lifespan of 2500 cycles. This work may advance high-energy aqueous batteries to next-generation scalable energy storage.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Natl Sci Rev
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China