Triggering the theoretical capacity of Na1.1V3O7.9 nanorod cathode by polypyrrole coating for high-energy zinc-ion batteries

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 446; p. 137069
• Main Authors: Islam, Saiful, Lee, Seunggyeong, Lee, Seulgi, Hilmy Alfaruqi, Muhammad, Sambandam, Balaji, Mathew, Vinod, Hwang, Jang-Yeon, Kim, Jaekook
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-10-2022
• Subjects: High specific capacity; Layered sodium vanadium oxide nanorods; Polypyrrole coating; Zn2+ (de-)intercalation; Zn2+ (de-)intercalation; Polypyrrole coating; Layered sodium vanadium oxide nanorods; High specific capacity
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.137069

•The PPy-coated Na1.1V3O7.9 particles are prepared via microwave-assisted hydrothermal method.•The PPy-coated Na1.1V3O7.9 particles are used for Zn-ion battery cathode applications.•The PPy coating enhances electronic conductivity and promotes high ionic diffusion.•The PPy-coated NVO cathode demonstrates enhanced electrochemical properties.
The exploration of advanced cathode materials for aqueous rechargeable zinc-ion batteries (ZIBs) is currently a major research topic. In this study, we propose the microwave-assisted hydrothermal synthesis of polypyrrole (PPy)-coated Na1.1V3O7.9 (P-NVO) nanorods for the first time as a high-energy and high-power cathode material for ZIBs. The highly conductive PPy surface-coating layer is significant to enhance the electronic conductivity and Zn2+ diffusion kinetics, leading to utilize the V3+/V4+/V5+ multiple redox reactions of the NVO cathode in ZIBs. Compared to the NVO cathode, therefore, the P-NVO cathode offers higher discharge capacity, power capability and cycling stability; in particular, PPy coating triggers the full theoretical capacity of the NVO cathode (527 mAh g−1 with ∼ 3 mol Zn insertion per formula unit) and directly reflects a superior energy density of 408 Wh kg−1. Even at a high current density of 6000 mA g−1, the P-NVO cathode shows unprecedented cycling stability over 1100 cycles without capacity loss. Galvanostatic intermittent titration technique, cyclic voltammetry, in situ X-ray diffraction, and ex situ X-ray absorption near edge structure analyses are combined to verify the superior Zn storage mechanism of the P-NVO cathode.