Constructing Three-Dimensional Structured V₂O₅/Conductive Polymer Composite with Fast Ion/Electron Transfer Kinetics for Aqueous Zinc-Ion Battery

Rechargeable aqueous zinc-ion batteries (ZIBs) are recognized as potential alternative devices for economical energy storage applications. However, the instable structure of cathodes and sluggish Zn2+ diffusion kinetics are the major challenges facing ZIBs. Here, intercalating conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) into vanadium oxide (named as PEDOT-VO) is designed to enhance the structure stability, Zn2+ intercalation/deintercalation, and electron transfer kinetics of V2O5. The larger interlayer spacing of 13.95 Å (compared to 4.38 Å for bare V2O5) and the three-dimensional structure are constructed by conductive polymer intercalation. As ZIB cathode materials, the as-prepared PEDOT-VO cathodes deliver a high specific capacity of 370.5 mA h g–1 at 0.5 A g–1 and 175 mA h g–1 even at 50 A g–1. Moreover, the long-life cycling of over 1000 cycles with a specific capacity of 310.1 mA h g–1 is also achieved. The superior electrochemical properties are ascribed to enlarged interlayer spacing and improved reaction kinetics. Quantification calculation results reveal that pseudocapacitance mainly contributes to the zinc-ion storage, leading to an ultrahigh rate capability.