Design and synthesis of inorganic-organic hybrid microstructures

Vanadium oxide-polypyrrole (V2O5-PPy) hybrid aerogels were prepared using t hree different strategies. These approaches were focused on either sequenti al or consecutive polymerization of the inorganic and organic networks. The hybrid microstructure differed greatly depending on which synthesis approa ch was used. Microcomposite aerogels were synthesized by encapsulating a di spersion of preformed PPy in a V2O5 gel. In the second approach, pyrrole wa s polymerized and doped within the pole volume of a preformed V2O5 gel. The hybrid microstructure of these materials was nanometer scaled but inhomoge neous. When the inorganic and organic precursors were allowed to polymerize simultaneously, the resulting gels exhibited a nanometer-scaled microstruc ture with a homogeneous distribution of the PPy and the V2O5. Through this route, a suitable microstructure and composition for a lithium secondary ba ttery cathode were obtained. Undoped material with a composition of [PPy](0 .8) V2O5 exhibited a lithium intercalation capacity comparable to that of V 2O5 aerogel. For the full benefit of the PPy phase to be achieved, a suitab le doping procedure is still required to oxidize the PPy into its high cond uctivity state while preserving the inorganic structure. (C) 1999 Elsevier Science Ltd. All rights reserved.