Enhancement of Both Ionic Conductivity and Permittivity of the High Polymer Film P(EO)n-CuBr2 under Hydrostatic Pressure (Ⅰ)－Discovery of Pressure Effects of Three Different Phases

With the addition of different weight of CuBr2 (ratio n =[EO]/[Cu]=4, 8, 12, 16, 24) to polyethylene oxide (molecular weight 5106), a series of high polymer ionic conductors P(EO)n-CuBr2 were prepared. Both complex impedance spectra of samples in the hydrostatic pressure range from 0.1 to 350 MPa and alternating current conductivity of samples in the pressure range from 0.1 to 2 400 MPa were measured in detail. Results show that the pressure dependence of conductivity can be decomposed into four linear parts. According to the phase analysis from X-ray diffraction patterns, it is found that three of the four straight lines correspond to the pressure effects of the amorphous phase of PEO, the crystalline phase of PEO, and the new phase of CuBr2. Hence, the composition dependence of the corresponding activation volume and cutoff pressure of the three types of conductivity-pressure effects can be calculated.