Nanoparticles of polypyrrole and their effect on mediating Li ion transport from liquid electrolyte to cathode

Abstract

Nano-scale particles of polypyrrole (PPy) have been synthesized by polymerizing the respect monomer in the presence of its substituted homologue with oxyethylene (POE) oligomers as the substitute groups. The polymerization was carried out by introducing an aqueous solution of oxidant into the tetrahydrofurane (THF) solution of the monomers. The particles obtained possess brush-like architectures in the dispersing medium, and their sizes in dry state fall into the range of 10 to 40 nm according to TEM analysis. When dispersed by a low content (< 0.1 wt %) in an aprotic organic solvent, the nanoparticles synthesized have been found to affect the conduction of lithium ion. The effect is interpreted as a significant reduction in the electrical resistance at the electrode/electrolyte interface according to gain-phase impedance measurement. This has been attributed to the mediating role of the graft POE chains on the colloidal particles.