Polymer Aukali-Metal Polyiodides with Variable Ionic and Electronic Conductivities

Alkali metal polyiodide complexes of polyethers, of the type (polymer)nMIx, [Polymer - poly(ethylene oxide), PEO; poly(propylene oxide), PPO; or poly-(bis(methoxyethoxyethoxy)phosphazene), MEEP, and M - Li or Na] have been prepared and characterized in order to elucidate the nature of the observed ionic and electronic conductivities. Raman spectra of the polyiodide complexes indicate that the relative concentrations of the polyiodide species (such as I3- and higher polyiodides) depend on the salt concentration in the polymer as well as on the iodine to cation ratio. The ionic conduction can best be described by a free volume (VTF) mechanism where both polymer motion and ion mobility are activated processes. The magnitude of the electronic and ionic conductivities are a function of polymer to salt ratio as well as iodine content.