Tuning Zn2+ coordination environment to suppress dendrite formation for high-performance Zn-ion batteries

• Published in: Nano energy Vol. 80; p. 105478
• Main Authors: Qin, Runzhi, Wang, Yuetao, Zhang, Mingzheng, Wang, Yan, Ding, Shouxiang, Song, Aoye, Yi, Haocong, Yang, Luyi, Song, Yongli, Cui, Yanhui, Liu, Jian, Wang, Ziqi, Li, Shunning, Zhao, Qinghe, Pan, Feng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2021
• Subjects: Coordination environment; Dendrite suppression; Ethylene glycol; Zn ion batteries; Ethylene glycol; Dendrite suppression; Zn ion batteries; Coordination environment
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2020.105478

The short-circuit issue induced by Zn dendrite growth restricts the commercialization of rechargeable aqueous Zn-ion batteries (ZIBs). Herein, ethylene glycol (EG), a representative of dihydric alcohols, is applied in the aqueous electrolyte to inhibit the detrimental dendrite growth on Zn anode. Our work demonstrates a uniform Zn plating/stripping in H2O/EG hybrid electrolyte with cycling lifespan of up to 2668 h at 0.5 mA cm−2, which is made possible by the substitution of EG for H2O in the solvation sheath of Zn2+ ions. Such a change in the coordination environment of Zn2+ gives rise to decreased diffusivity of the ions and increased over-potential for nucleation, further resulting in even deposition morphology rather than large-scale dendrites. Side reactions are also circumvented by the formation of hydrogen bonds. All these aspects work in synergy to promote the cyclability of the assembled full battery. The low-cost aqueous electrolyte identified in this work opens up new opportunities for manipulating the coordination environments of Zn2+ ions and optimizing the Zn deposition morphology during the design of high-performance ZIBs.
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•Cycling performance of Zn electrodes is greatly enhanced via adding ethylene glycol (EG).•Tuning Zn2+ coordination by EG contributes to uniform Zn deposition, as well as higher CE.•Adding EG benefits for cycling performance and low-temperature performance of Zn/ZnVO full batteries.