Polyaniline Encapsulated Amorphous V₂ O₅ Nanowire-Modified Multi-Functional Separators for Lithium-Sulfur Batteries

Designing multi-functional separators is one of the effective strategies for achieving high-performance lithium-sulfur (Li-S) batteries. In this work, polyaniline (PANI) encapsulated amorphous vanadium pentoxide (V₂ O₅ ) nanowires (general formula V₂ O₅ ·nH₂ O and abbreviated as VOH) are synthesized by a facile in situ chemical oxidative polymerization method, and utilized as a basic building block for the preparation of functional interlayers on the commercial polypropylene (PP) separator, generating a VOH@PANI-PP separator with multi-functionalities. Compared to the crystalline V₂ O₅ , the amorphous V₂ O₅ shows enhanced properties of polysulfide adsorption, catalytic activity, as well as ionic conductivity. Therefore, within the VOH@PANI-PP separator, the amorphous V₂ O₅ nanowire component contributes to the strong adsorption of polysulfides, the high catalytic activity for polysulfides conversion, and the high ionic conductivity. The PANI component further strengthens the above effects, improves the electrical conductivity, and enhances the flexibility of the modified separator. Benefiting from the synergistic effects, the VOH@PANI-PP separator effectively suppresses polysulfide shuttling and improves the cycling stability of its composed Li-S batteries. This work provides a new research strategy for the development of efficient separators in rechargeable batteries by judiciously integrating the amorphous metal oxide with a conductive polymer.