Chemical and electrochemical characterization of a novel nanocomposite formed from V₂O₅ and poly(N-propane sulfonic acid aniline), a self-doped polyaniline

Synthesis and characterization of new nanocomposites of V₂O₅ and a sulfonated, alkylated polyaniline derivative [poly (N-propane sulfonic acid aniline), PSPAN] are described. Two types of PSPAN-V₂O₅ nanocomposites have been produced, one by reaction of vanadium triisopropoxide solutions with N-propane sulfonic acid aniline and one by addition of H₂O₂ to these same solutions. Nanocomposites are characterized using thermal gravimetric analysis, differential scanning calorimetry (DSC), cyclic voltammetry, chronopotentiometry, and impedance spectroscopy. The increase of the 001 reflection spacing, X-ray diffraction results show that the polymer is intercalated into the V₂O₅ interlayer region, consistent with the nanocomposite nature of the material. The DSC and infrared data suggest that water coordinated to vanadium sites exposed to the interlayer region is lost during formation of the nanocomposite. SEMs show that, in contrast to the relatively flat and featureless V₂O₅·1.6H₂O thin films, the nanocomposites are highly textured and have quite small feature sizes. Electrochemical results show that some of the nanocomposites have larger specific capacity (307 Ah/kg) and faster reduction kinetics than V₂O₅·16.H₂O and similar cyclability. The relevance of these results to general approaches to the production of nanocomposites for Li secondary battery cathodes is discussed.