Dual-stage K+ ion intercalation in V2O5-conductive polymer composites

Abstract

We reported that the incorporation of a conductive polymer into V₂O₅ materials resulted in an increased interlayer distance of 2.2 nm, favoring K⁺ ion storage in aqueous electrolyte. In situ X-ray diffraction showed that during charging, K⁺ ions were first inserted into the interlayer region of V₂O₅ through pseudocapacitive intercalation and then continued to be inserted into the [VO₆] bi-layer region via diffusion-limited intercalation. This reversible dual-stage insertion/extraction mechanism provides new battery chemistry allowing the storage of around 50% more alkali ions in the intralayer region besides van der Waals gaps.