In the polymer electrolyte, lots of salt have been studied and synthesized in many laboratories. In the previous our work[1,2], we found that the SiO2 (-7 nm, Degussa-Huls), which had the OH- and (CH3)3 surface groups, could help to enhance the ionic conductivity and the interfacial stability. We used as a plasticizer. It has the four CN groups at the end of chains. It was helpful to enhance the ionic conductivity, as respected. The ionic conductivity of the composite electrolytes was about 5.0ⅹ10-5 S/cm at room temperature. In addition, we conducted the charge/discharge test with LiMn2O4 at room temperature and 45 °C. The retention of 1st cycle to 100th cycle was 74 % at 45°C.