The polyethylene oxide/succinonitrile/lithium perchlorate(PEO/SN/LiClO4) composite electrolytes with different PEO/SN molar ratios were prepared and their room temperature(RT) ionic conductivities were detected. The influences of phase structure and morphology on ionic conductivity of composite electrolytes were characterized via wide-angle X-ray diffraction and polarized optical microscopy. The results show that with addition of PEO,the spherulitic morphology for plastic crystal phase of SN gradually disappears and the liquid phase of SN as a plasticizer role to PEO starts to appear,which is beneficial to the enhancement of RT ionic conductivity,thus the PEO/SN/LiClO4(molar ratio 50/45/5) sample shows the highest RT ionic conductivity of 1.5×10-3 S/cm. With PEO molar fraction above 50%,the RT ionic conductivity of composite electrolytes decreases due to increasing crystallinity of PEO.
