Electrochemical Hydrophobic Tri‐layer Interface Rendered Mechanically Graded Solid Electrolyte Interface for Stable Zinc Metal Anode

• Published in: Angewandte Chemie Vol. 136; no. 9
• Main Authors: Liu, Chaozheng, Xu, Wangwang, Zhang, Lei, Zhang, Daotong, Xu, Weina, Liao, Xiaobin, Chen, Weimin, Cao, Yizhong, Li, Mei‐Chun, Mei, Changtong, Zhao, Kangning
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 26.02.2024
• Subjects: Electric power grids; Electrochemical Tri-Layer Interface; Electrochemistry; Electrodes; Electrolytes; Energy storage; Hydrophobic; Hydrophobicity; Interface stability; Ionic Liquid; Ionic liquids; Mechanically Graded Solid Electrolyte Interface; Solid electrolytes; Zinc; Zinc Battery
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202318063

The aqueous zinc‐ion battery is promising as grid scale energy storage device, but hindered by the instable electrode/electrolyte interface. Herein, we report the lean‐water ionic liquid electrolyte for aqueous zinc metal batteries. The lean‐water ionic liquid electrolyte creates the hydrophobic tri‐layer interface assembled by first two layers of hydrophobic OTF− and EMIM+ and third layer of loosely attached water, beyond the classical Gouy–Chapman–Stern theory based electrochemical double layer. By taking advantage of the hydrophobic tri‐layer interface, the lean‐water ionic liquid electrolyte enables a wide electrochemical working window (2.93 V) with relatively high zinc ion conductivity (17.3 mS/cm). Furthermore, the anion crowding interface facilitates the OTF− decomposition chemistry to create the mechanically graded solid electrolyte interface layer to simultaneously suppress the dendrite formation and maintain the mechanical stability. In this way, the lean‐water based ionic liquid electrolyte realizes the ultralong cyclability of over 10000 cycles at 20 A/g and at practical condition of N/P ratio of 1.5, the cumulated areal capacity reach 1.8 Ah/cm2, which outperforms the state‐of‐the‐art zinc metal battery performance. Our work highlights the importance of the stable electrode/electrolyte interface stability, which would be practical for building high energy grid scale zinc‐ion battery. An electrochemical hydrophobic tri‐layer interface is developed through the lean‐water ionic liquid electrolyte design to create stable electrode/electrolyte interface. The OTF‐ rich interface facilitates the formation of mechanically graded solid electrolyte interface. As a result, the lean‐water ionic liquid electrolyte enabled zinc metal battery stable operation at practical condition and under wide temperature range.