Tham, N. N., Chien, S. W., Wang, W., Yang, H., Li, X., Lim, P. C., Xing, Z., Chiam, S. Y., Liu, Z., & Ding, N. (2026). Quantitative decoupling of concurrent ion-storage mechanisms in aqueous Zn-ion batteries. Energy Storage Materials, 88, 105093. https://doi.org/10.1016/j.ensm.2026.105093
Abstract:
Rechargeable aqueous Zn-ion batteries have attracted extensive research interest for large-scale energy storage owing to their inherent safety and low cost. However, their ion-storage mechanisms remain controversial, as either Zn2+ or H+ may act as the dominant charge carrier. To resolve this controversy, we herein report, for the first time, a quantitative decoupling of the capacity contributions from Zn2+ and H+ intercalation into a VO2 cathode. To ensure analytical accuracy, the cathode surface is carefully cleaned to remove a passivation layer formed by pH changes. This quantitative analysis enables us to identify two distinct charge-storage mechanisms determined by the choice of zinc salt in the electrolyte. In mildly acidic 3 M zinc sulfate (pH 5.1), discharge proceeds via Zn2+/H+ co-intercalation, with both species contributing comparably beyond 50 % discharge. In contrast, in more acidic 3 M zinc triflate (pH 3.9), the high- and low-voltage plateaus are dominated by H+ and Zn2+ intercalation, respectively. Furthermore, we elucidate that the additional capacity observed in the zinc triflate electrolyte originates from surface-mediated processes associated with increased interstitial oxygen. These findings provide quantitative mechanistic insight into ion storage and offer guidance for the rational design of high-performance aqueous zinc-ion batteries.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - GAP Fund
Grant Reference no. : I22D1AG049
This research / project is supported by the Agency for Science, Technology and Research - Manufacturing, Trade, and Connectivity Programmatic Fund
Grant Reference no. : M24N5b0037