STRUCTURAL AND DYNAMICAL PROPERTIES OF POLYMER ELECTROLYTES PPO-LICLO4

The structure and dynamics of a prototype of polymer electrolytes, PPO -LiClO4, have been investigated using neutron diffraction and quasi-el astic neutron scattering (QENS). The aim is to gain insights into micr oscopic structures and processes that may be of importance for the ion ic conductivity mechanism. The diffraction experiments reveal large st ructural changes on an intermediate length scale, 4-10 Angstrom, as th e polymer is doped with salt. The effects may partly be explained by l ocal segmental ordering of the polymer ether-oxygens around the solvat ed cations. The QENS results indicate that the segmental motions, whic h have been discussed to be of vital importance for the ionic mobility , slow down considerably when coordinated to cations. The results are discussed in relation to proposed models for the structure and the con ductivity mechanism.