Organic–Inorganic Hybrid Cathode with Dual Energy‐Storage Mechanism for Ultrahigh‐Rate and Ultralong‐Life Aqueous Zinc‐Ion Batteries

• Published in: Advanced materials (Weinheim) 2022-02, Vol.34 (6), p.e2105452-n/a
• Main Authors: Ma, Xuemei, Cao, Xinxin, Yao, Mengli, Shan, Lutong, Shi, Xiaodong, Fang, Guozhao, Pan, Anqiang, Lu, Bingan, Zhou, Jiang, Liang, Shuquan
• Format: Article
• Language: English
• Subjects: cathode materials; Cathodes; Chelation; Density functional theory; Diffusion barriers; Electric potential; Electrode materials; Electronic design automation; energy density; Energy storage; Ethylenediamine; Ion diffusion; Materials science; organic–inorganic hybrid materials; Storage batteries; Vanadium oxides; vanadium‐based materials; Voltage; Zinc; zinc‐ion batteries
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202105452

The exploitation of cathode materials with high capacity as well as high operating voltage is extremely important for the development of aqueous zinc‐ion batteries (ZIBs). Yet, the classical high‐capacity materials (e.g., vanadium‐based materials) provide a low discharge voltage, while organic cathodes with high operating voltage generally suffer from a low capacity. In this work, organic (ethylenediamine)–inorganic (vanadium oxide) hybrid cathodes, that is, EDA‐VO, with a dual energy‐storage mechanism, are designed for ultrahigh‐rate and ultralong‐life ZIBs. The embedded ethylenediamine (EDA) can not only increase the layer spacing of the vanadium oxide, with improved mobility of Zn ions in the V–O layered structure, but also act as a bidentate chelating ligand participating in the storage of Zn ions. This hybrid provides a high specific capacity (382.6 mA h g−1 at 0.5 A g−1), elevated voltage (0.82 V) and excellent long‐term cycle stability (over 10 000 cycles at 5 A g−1). Assistant density functional theory (DFT) calculations indicate the cathode has remarkable electronic conductivity, with an ultralow diffusion barrier of 0.78 eV for an optimal Zn‐ion diffusion path in the EDA‐VO. This interesting idea of building organic–inorganic hybrid cathode materials with a dual energy‐storage mechanism opens a new research direction toward high‐energy secondary batteries. A dual energy‐storage mechanism is detected in an organic (ethylenediamine (EDA))–inorganic (vanadium oxide) hybrid cathode. Both the EDA ligand and the V–O layer can participate in Zn‐ion storage synchronously. Benefiting from the advanced mechanism, this hybrid provides a high specific capacity, elevated voltage, and excellent long‐term cycle stability.