Microscopic investigation of ionic conductivity in alkali metal salts-poly(ethylene oxide) adducts

We present conductivity, N.M.R. and D.S.C. measurements in two P(EO) complexes : P(EO) 8LiCF3SO3 and P(EO) 10NaI. From N.M.R. experiments, we deduce the respective amount of crystalline and elastomeric phases at all temperatures, as well as the salt concentration in these various phases. The elastomeric phase is shown to be responsible of the ionic conductivity at all temperatures, and to be very dilute (n ≅ 25 just above the pure P(EO) melting point. The high melting salt-rich complexes are found surstoechiometric (n ≅ 3.5). The various factors affecting the temperature dependence of the conductivity are discussed, as well as the kinetics problems.