Large-scale energy storage is critical for integrating intermittent renewable power sources such as solar and wind into the grid. Aqueous zinc metal batteries stand out for their safety, low cost, and high theoretical capacity. However, their commercial viability is hampered by persistent challenges: dendrite formation, low Coulombic efficiency, and parasitic side reactions that consume active zinc and generate hydrogen gas. Past research has mainly linked hydrogen release to competitive reactions during zinc plating, overlooking the stripping process. These issues undermine long-term stability and efficiency. Due to these challenges, a deeper investigation into interfacial hydrogen release and potential suppression strategies is urgently needed.
A research team from the University of Science and Technology of China and collaborating institutions published (DOI: 10.1016/j.esci.2024.100330) their findings on May, 2025, in eScience. The study reveals unexpected mechanisms of hydrogen generation and introduces an effective solution using molecular additives. By forming a gradient solid electrolyte interphase at the electrode surface, the team achieved significantly improved battery reversibility and stability, offering fresh insights into designing next-generation aqueous zinc batteries.
The researchers employed advanced in situ characterization techniques, including operando gas chromatography, synchrotron infrared spectroscopy, and electrochemical quartz crystal microbalance, to decouple zinc plating and stripping processes. They discovered that hydrogen release does not solely originate from electrochemical hydrogen evolution during plating, but also from accelerated chemical corrosion of freshly exposed zinc during stripping. This overlooked phenomenon explains persistent inefficiencies in zinc anodes.
To address the problem, the team systematically screened organic molecules with different functional groups. They found a strong correlation between the adsorption strength of additives and their ability to suppress hydrogen release. Among the candidates, cysteamine (MEA) was most effective, forming a unique gradient solid electrolyte interphase with an outer nitrogen-rich amorphous layer and an inner sulfur-rich crystalline layer. This protective barrier blocks water interaction with zinc, thereby inhibiting side reactions and promoting uniform zinc deposition.
Electrochemical tests demonstrated remarkable improvements: cells with MEA achieved over 4000 stable cycles at > 99.5% Coulombic efficiency, compared with only 189 cycles in additive-free electrolytes. The approach also extended the lifespan of full zinc–manganese dioxide cells and pouch cells, proving practical feasibility.
“Our work redefines the understanding of hydrogen evolution in zinc batteries,” said Prof. Gongming Wang, corresponding author of the study. “The surprising discovery that hydrogen release during stripping is largely driven by chemical corrosion highlights a long-ignored mechanism. By introducing cysteamine as a simple electrolyte additive, we demonstrate a cost-effective yet powerful strategy to build a stable interphase that suppresses hydrogen generation. This not only enhances cycle life but also provides new guidelines for designing electrolyte systems to unlock the full potential of aqueous zinc batteries.”
The findings open new opportunities for the commercialization of aqueous zinc metal batteries in large-scale renewable energy storage. By addressing hydrogen release at both plating and stripping stages, the additive strategy ensures higher reversibility, longer cycle life, and improved safety. Importantly, cysteamine is effective at very low concentrations, making the approach economically viable for industrial application. Beyond zinc batteries, the study provides a blueprint for tailoring interfacial chemistry in other metal-based aqueous systems. Such advances bring the vision of affordable, sustainable, and safe energy storage solutions closer to reality, supporting the global transition toward net-zero carbon energy infrastructure.
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References
DOI
10.1016/j.esci.2024.100330
Original Source URL
https://doi.org/10.1016/j.esci.2024.100330
Funding Information
We acknowledge the support by the Fundamental Research Funds for the National Natural Science Foundation of China (22379135), the Fundamental Research Funds for the Central Universities (WK2060000016), and the Collaborative Innovation program of Hefei Science Center, CAS.
About eScience
eScience – a Diamond Open Access journal cooperated with KeAi and published online at ScienceDirect. eScience is founded by Nankai University (China) in 2021 and aims to publish high quality academic papers on the latest and finest scientific and technological research in interdisciplinary fields related to energy, electrochemistry, electronics, and environment. eScience provides insights, innovation and imagination for these fields by built consecutive discovery and invention. Now eScience has been indexed by SCIE, CAS, Scopus and DOAJ. Its first impact factor is 36.6, which is ranked first in the field of electrochemistry.