Eutectic Electrolytes with Doubly‐Bound Water for High‐Stability Zinc Anodes. (26th October 2022)

• Record Type: Journal Article
• Authors: Han, Dong; Sun, Tianjiang; Zhang, RuoChen; Zhang, Weijia; Ma, Tao; Du, Haihui; Wang, Qiaoran; He, Dan; Zheng, Shibing; Tao, Zhanliang
• Is Part Of: Advanced functional materials. Volume 32:Number 52(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-26
• Subjects: aqueous zinc‐ion batteries -- desolvation processes -- doubly‐bound water -- eutectic electrolytes -- zinc anodes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202209065
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: The aqueous zinc‐ion battery has the advantages of environmental friendliness, safety, and reliability, which is expected to be used for large‐scale energy storage. However, due to the high activity of water, the hydrogen evolution reaction (HER) easily occurs on the surface of the zinc anode during the charge–discharge process, which is accompanied by corrosion, by‐products, and dendrite formation. Herein, a new‐type eutectic electrolyte consisting of ZnCl2, tetramethylurea (TMU), and H2 O with the optimal molar ratio of 1:3:1 (ZT‐1) is developed for the high‐stability zinc anodes. The H2 O in this system is doubly bound through the coordination with Zn 2+ and the hydrogen bonding with TMU, thus leading to the greatly inhibited activity of H2 O. In addition, the H2 O and TMU are successively stripped during the desolvation process of ZnCl2 (TMU)(H2 O), followed by the deposition of [ZnCl2 ] at the zinc interface. In this way, the tendency of HER, corrosion, dendrites, and by‐products induced by the decomposition of H2 O molecules at the zinc interface is minimized, enabling a much more stable plating/stripping process of Zn 2+ . Consequently, the Zn//Zn symmetric cell can stably cycle for >2000 h, while the Zn//Cu half cell can stably cycle 800 times with an average Coulombic efficiency of 99.5%. Abstract : The H2 O in ZT‐1 electrolyte is doubly bound by the coordination with Zn 2+ and the hydrogen bonding with tetramethylurea (TMU), leading to the greatly inhibited activity of H2 O. The H2 O and TMU are successively stripped during the desolvation process of [ZnCl2 (TMU)(H2 O)], followed by the deposition of [ZnCl2 ] at the interface, reducing the direct contact of H2 O and Zn interface.