Ionic conductivity of polymer solid electrolyte prepared from poly[epichlorohydrin‐co‐(ethylene oxide)] of high ethylene oxide content

High molecular weight poly[epichlorohydrin‐ co ‐(ethylene oxides)] [P(EH/EO)s] composed of high ethylene oxide (EO) content were synthesized by a coordination anionic polymerization of epichlorohydrin (EH) and EO and were used as matrixes for polymer solid electrolytes. The glass‐transition temperature of P(EH/EO)s was linearly shifted to the low temperature with the increase of EO content. The melting temperature attributable to the EO crystalline phase was detected in P(EH/EO)s having EO units of >81 mol %, but their heat of fusion was small. The temperature dependence of ionic conductivity of the P(EH/EO)s doped with LiClO 4 was expressed by WLF equation. P(EH/EO), whose EO content was 81 mol %, showed the highest ionic conductivity at 30°C when LiClO 4 was doped in the concentration of [Li]/[–O–] = 0.05, and it was 2.2 × 10 −5 S/cm at 30°C.