Metal Oxide Aerogels: A New Horizon for Stabilizing Anodes in Rechargeable Zinc Metal Batteries

• Published in: Advanced energy materials 2023-05, Vol.13 (20), p.n/a
• Main Authors: Shi, Zhenhai, Chen, Suli, Xu, Zijian, Liu, Zhanming, Guo, Junhong, Yin, Jian, Xu, Pengwu, Zhang, Nan, Zhang, Wenli, Alshareef, Husam N., Liu, Tianxi
• Format: Article
• Language: English
• Subjects: Aerogels; Anodes; Cerium oxides; dendrite growth; Deposition; Energy storage; Manganese dioxide; Metal oxides; Nanochannels; Oxygen; oxygen vacancy; Rechargeable batteries; side reactions; Zinc; Zn anodes; Zn utilization
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202300331

Dendritic deposition and side reactions have been long‐standing interfacial challenges of Zn anode, which have prevented the development of practical aqueous zinc‐based batteries. Herein, an oxygen vacancy‐rich CeO2 aerogel (VAG‐Ce) interface layer that simultaneously integrates Zn2+ selectivity, porosity, and is lightweight is reported as a new strategy to achieve dendrite‐free and corrosion‐free Zn anodes. The well‐defined and uniform nanochannels of VAG‐Ce can act as ion sieves that redistribute Zn2+ at the Zn anode surface by regulating Zn2+ flux, leading to uniform Zn deposition and significantly suppressing dendrite growth. Importantly, the abundant oxygen vacancies exposed on VAG‐Ce surface can strongly capture SO42−, forming a negatively charged layer that can attract Zn2+ and accelerate the Zn2+ migration kinetics, while the subsequent repulsion of additional anions can effectively suppress the generation of (Zn4SO4(OH)6·xH2O) byproducts, thereby realizing very stable Zn anodes. Consequently, VAG‐Ce modified Zn anode (VAG‐Ce@Zn) enables a long‐term lifespan over 4000 h at 4 mA cm−2 and a record‐high cycle life of 1200 h is achieved under an ultrahigh 85% Zn utilization at 8 mA cm−2, which enables excellent capacity retention and cycling performance of VAG@Zn/MnO2 cells. This work contributes an innovative design concept by introducing oxygen vacancy‐rich aerogels and provides a new horizon for stabilizing Zn anode for large‐scale energy storage. An oxygen vacancy‐rich CeO2 aerogel is proposed as protective layer that can effectively suppress Zn dendrite and side reactions. Impressively, Zn anodes with the aerogel achievea record‐high 1200 h cycle life with 85% Zn utilization at 8 mA cm−2, enabling full cells with excellent electrochemical performance.