A study of stability of plasticized PEO electrolytes

Considerable research effort has been devoted to lowering the useful operating temperature of PEO–LiX polymer electrolytes to the ambient region. The most common approach has been that of adding liquid plasticizers, such as ethylene carbonate (EC) or propylene carbonate (PC), to the PEO–LiX matrix. In this paper, we have extensively studied EC plasticized LiCF3SO3·P(EO)10 and LiClO4·P(EO)10, measuring the conductivity, thermal characteristics and X-ray diffraction patterns of the electrolyte films. significant feature of the results is that the enhanced conductivity of the as-prepared films is transient and is not maintained on thermal cycling under vacuum. The systems are not thermodynamically stable due to a loss of the bulk of the plasticizer and this will impair their applications in devices.