Synthesis and Characterization of Polypyrrole/Vanadium Pentoxide Nanocomposite Aerogels
Technical rept. 1 Jun 97-31 May 98
CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
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Vanadium pentoxidepolypyrrole aerogel ARG composites were synthesized by sol-gel routes, and investigated as cathode materials in Li batteries. The primaly method utilized simultaneous polymerization of pyrrole and vanadium alkoxide precursors. Supercritical drying yielded high surface 150-257 sq mg aerogels with densities between 0.1 and 0.2 gcc. The interaction between the polypyrrole PPy and V2O5 aerogel in the nanocomposites was probed using IR spectroscopy. Our results suggest that the inorganic and organic components strongly interact, thus impeding the vanadium condensation process. Hence, the PPyV2O5 nanocomposites exhibited lower electrical conductivity with increased polypyrrole content. The deleterious effect of the conductive polymer on the bulk conductivity does not necessarily affect the electrochemical properties of these materials. Nanocomposite materials that were subjected to post-oxidative treatment show enhanced Li insertion capacity compared to the pristine ARG. The physical properties of these nanocomposite aerogels are different from microcomposites prepared by an alternate route, in which the oxide gel is formed in the presence of a dispersion of preformed micron-sized polypyrrole particles.
- Polymer Chemistry
- Laminates and Composite Materials