Oxygen defect enriched (NH4)2V10O25·8H2O nanosheets for superior aqueous zinc‐ion batteries

• Published in: Nano energy 2021-06, Vol.84, p.105876, Article 105876
• Main Authors: Cao, Jin, Zhang, Dongdong, Yue, Yilei, Wang, Xiao, Pakornchote, Teerachote, Bovornratanaraks, Thiti, Zhang, Xinyu, Wu, Zhong-Shuai, Qin, Jiaqian
• Format: Article
• Language: English
• Subjects: (NH4)2V10O25·8H2O nanosheets; Cathode; Energy storage; Oxygen defects; Zinc ion battery
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2021.105876

Aqueous zinc-ion batteries (ZIBs) are recognized as a highly competitive electrochemical energy storage systems due to the high safety and low cost, however, rational design of advanced cathodes with stable internal structures and fast Zn2+ diffusion channel remains challenging. Herein, we reported an advanced cathode of oxygen defect enriched (NH4)2V10O25·8H2O (NVOD) nanosheets with expanded tunnel structure, exceptional conductivity and superior structural stability for aqueous ZIBs, showing fast Zn2+ diffusion and excellent performance. The resulted ZIBs afford a remarkably high capacity (408mAhg−1 at 0.1 A g−1), ultrahigh stability (94.1% retention over 4000 cycles), and exceptional energy density (287 Wh kg−1), outperforming many cathodes of ZIBs. Furthermore, it is revealed that from theoretical and experimental studies the oxygen defects intrinsically contribute to the narrow bandgap and high electrical conductivity of NVOD to greatly boost the performance. The reversible storage of Zn2+ in NVOD is further illustrated via different in-situ characterization techniques. Moreover, the flexible soft-packaged batteries also demonstrate superior capacity retention of 91% after 200 cycles. Therefore, the exploration in NVOD materials with rich oxygen defects will supply an attractive approach for designing high-performance and flexible ZIBs. The oxygen defect enriched (NH4)2V10O25·8H2O (NVOD) nanosheets with expanded tunnel structure, exceptional conductivity and superior structural stability display fast Zn2+ diffusion and excellent performance as cathode of aqueous ZIBs. [Display omitted] •Oxygen defect enriched (NH4)2V10O25·8H2O (NVOD) nanosheets are synthesized by solution synthesis method.•NVOD nanosheets show the expanded tunnel structure, exceptional conductivity, and superior structural stability.•NVOD nanosheets display high capacity of 418mAhg−1, and exceptional stability with a retention of 94.1% after 4000 cycles at 5 A g−1.•The soft-packaged ZIBs display long-term cyclability of 91% after 200 cycles, with remarkable flexibility, and modular integration.