Design and synthesis of inorganic-organic hybrid microstructures

Vanadium oxide-polypyrrole (V2O5-PPy) hybrid aerogels were prepared using three different strategies. These approaches were focused on either sequential or consecutive polymerization of the inorganic and organic networks. The hybrid microstructure differed greatly depending on which synthesis approach was used. Microcomposite aerogels were synthesized by encapsulating a dispersion of preformed PPy in a V2O5 gel. In the second approach, pyrrole was polymerized and doped within the pole volume of a preformed V2O5 gel. The hybrid microstructure of these materials was nanometer scaled but inhomogeneous. When the inorganic and organic precursors were allowed to polymerize simultaneously, the resulting gels exhibited a nanometer-scaled microstructure with a homogeneous distribution of the PPy and the V2O5. Through this route, a suitable microstructure and composition for a lithium secondary battery cathode were obtained. Undoped material with a composition of [PPy](0.8) V2O5 exhibited a lithium intercalation capacity comparable to that of V2O5 aerogel. For the full benefit of the PPy phase to be achieved, a suitable doping procedure is still required to oxidize the PPy into its high conductivity state while preserving the inorganic structure. (C) 1999 Elsevier Science Ltd. All rights reserved.