Optimizing Molecular Weight of Polyethylene Glycol as an Additive for Stabilizing Zn Metal Anode in Aqueous Electrolyte

Abstract

Polyethylene glycol (PEG) additives have attracted significant attention as a cost-effective approach for modifying the deposition behavior of Zinc (Zn) anodes. In this study, we investigated the effectiveness of PEG additives in 1 M ZnSO4 aqueous electrolytes, specifically examining the effect of PEG molecular weight on Zn deposition. By exploring the adsorption of PEG polymers with different molecular weights, we identified the PEG with a molecular weight of 300 g mol−1 (PEG300) as the most suitable polymer. In terms of electrochemical performance, Zn anodes exhibited steady cycling for 232 cycles with high reversibility in 1 M ZnSO4 electrolyte with 0.1 wt.% PEG300. By contrast, Zn anodes using the control electrolyte of 1 M ZnSO4 began to fail after only 70 cycles. These findings highlight the potential of PEG300 as a simple and adaptable additive for significantly extending the longevity of Zn metal anodes. © The Author(s), under exclusive licence to Korean Institute of Chemical Engineers, Seoul, Korea 2024.