Solubility of Inorganic Salts in Polyethylene Oxide and Effects of Molecular Weight of Polyethylene Oxide and Salt Species on the Ionic Conductivity (II)

Abstract

Solubility of MX₂ type metal salts in polyethylene oxide (PEO) with different molecular weight (200-600) was determined and summarized. The terminal hydroxyl groups of PEO were found to be effective in increasing the salt solubility. There was however no clear relationship between the solubility in PEO and that in water. The effect of salt concentration on the ionic conductivity showed a maximum because of the compensation of the increase of carrier ion concentration and decrease of their mobility. The PEOs containing MX₂ type salts show similar characteristics to those of PEOs containing MX type salts. The ionic conductivity of PEOs containing these salts shows a positive relation with the lattice energy of the salts contained. PEOs with lower molecular weight and containing salts with lower lattice energy provided higher ionic conductivity.