Poly(3,4-ethylenedioxythiophene) encapsulating hydrated vanadium oxide nanobelts boosts their conductivity and zinc-ion storage properties

Abstract

Thanks to its changeable open framework and variable valence states, vanadium oxide (VO) is recognized as an ideal electrode material for aqueous zinc-ion batteries (AZIBs). However, these characteristics also lead to structural collapse and dissolution of VO in aqueous electrolytes during long charging/discharging cycles. In this study, we propose a strategy to polymerize conductive polymers on the surface of VO, isolating it from direct contact with an aqueous electrolyte, thereby improving both conductivity and stability. Specifically, poly(3,4-ethylenedioxythiophene), abbreviated as PEDOT, was coated on the surface of V₂O₅·nH₂O (VOH) nanobelts (VOH@PEDOT) through a simple stirring step. The dual-improved conductivity and stability, along with the intrachain electron transfer of PEDOT, significantly boost the excellent electrochemical performance of the battery. Density functional theory (DFT) calculations further support that coating with PEDOT can improve the conductivity and stabilize the structure of VOH. As expected, VOH@PEDOT exhibits an outstanding specific capacity of 432 mA h g⁻¹ at 0.1 A g⁻¹ and retains 323 mA h g⁻¹ after 100 cycles. Coating VOH with conductive PEDOT serves as a straightforward strategy for preventing VOH from structural collapse and improving the conductivity. Additionally, the intrachain electron transfer of PEDOT provides new insights into energy storage system applications.