Dendrite‐Free Zinc Anodes Enabled by Exploring Polar‐Face‐Rich 2D ZnO Interfacial Layers for Rechargeable Zn‐Ion Batteries

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-05, Vol.20 (18), p.e2306827-n/a
• Main Authors: Hu, Xueqing, Borowiec, Joanna, Zhu, Yijia, Liu, Xiaopeng, Wu, Ruiqi, Ganose, Alex M., Parkin, Ivan P., Boruah, Buddha Deka
• Format: Article
• Language: English
• Subjects: Anodes; Aqueous electrolytes; Contact resistance; dendrite; Electrolytic cells; Electron transport; Hydrogen evolution; hydrophilicity; Ion plating; Nanorods; Rechargeable batteries; Thermal stability; zinc anodes; Zinc oxide; Zinc oxides; zinc‐ion batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202306827

Zinc metal is a promising candidate for anodes in zinc‐ion batteries (ZIBs), but its widespread implementation is hindered by dendrite growth in aqueous electrolytes. Dendrites lead to undesirable side reactions, such as hydrogen evolution, passivation, and corrosion, causing reduced capacity during prolonged cycling. In this study, an approach is explored to address this challenge by directly growing 1D zinc oxide (ZnO) nanorods (NRs) and 2D ZnO nanoflakes (NFs) on Zn anodes, forming artificial layers to enhance ZIB performance. The incorporation of ZnO on the anode offers both chemical and thermal stability and leverages its n‐type semiconductor nature to facilitate the formation of ohmic contacts. This results in efficient electron transport during Zn ion plating and stripping processes. Consequently, the ZnO NFs‐coated Zn anodes demonstrate significantly improved charge storage performance, achieving 348 mAh g−1, as compared to ZnO NRs (250 mAh g−1) and pristine Zn (160 mAh g−1) anodes when evaluated in full cells with V2O5 cathodes. One significant advantage of ZnO NFs lies in their highly polar surfaces, promoting strong interactions with water molecules and rendering them exceptionally hydrophilic. This characteristic enhances the ability of ZnO NFs to desolvate Zn2+ ions, leading to improved charge storage performance. The desolvation of solvated Zn2+ ions is crucial for achieving dendrite‐suppressive Zn anodes in high‐performance aqueous zinc‐ion batteries. The investigation of ZnO nanoflakes (NFs), which create artificial layers on Zn anodes, offers surfaces that are not only more polar than nanorods (NRs) morphologies but also enhance strong interactions with water molecules for exceptional hydrophilicity, facilitating the formation of ohmic contacts for efficient electron transport during Zn2+ plating/stripping processes.