Electrolyte Engineering in Aqueous Zn/MnO2 Batteries: Effects of pH and ZnSO4 on Electrochemical Behavior and Degradation Mechanisms
Year: 2025
Type: article
Abstract: Aqueous Zn/MnO2 batteries offer a promising avenue for grid-scale energy storage, yet their performance and longevity are critically dependent on electrolyte composition. This work investigates the influence of initial electrolyte pH (via H2SO4 addition, 0–0.5 M) and ZnSO4 concentration (0.5–3.0 M) on the electrochemical behavior and degradation pathways in Zn/β-MnO2 and Zn/α-MnO2 cells. A multi-faceted approach combining operando pH measurements, galvanostatic cycling, and physics-based continuum modeling coupled with parameter estimation was employed. Initial H2SO4 addition introduced a high-voltage discharge plateau, enhancing initial capacity; however, this benefit diminished rapidly over cycling with minimal impact on long-term stability. Parameter estimation linked capacity fade to decreasing fractions of active zinc manganese oxide (ZMO) material for both dissolution and insertion reactions, attributed to heterogeneous Zn hydroxysulfate precipitation, non-uniform MnO2 utilization, and material redistribution. ZnSO4 concentrations below 2.0 M significantly reduced discharge capacity, particularly for the MnO2 dissolution/ZMO formation pathway, confirming Zn2+ depletion limitations. These findings highlight the critical role of electrolyte engineering and provide actionable design principles for optimizing electrolyte formulations to improve the performance and durability of aqueous Zn/MnO2 batteries.
Authors: John C. Bernard, Ryan C. Hill, Zhongling Wang, Esther S. Takeuchi, Amy C. Marschilok, Shan Yan, Kenneth J. Takeuchi, Alan C. West
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,950
OpenAlex ID: W7083719611