Neutron-scattering studies of a polymer electrolyte, PPO-LiClO4

The structure and dynamics of a prototype polymer electrolyte, PPO-LiClO4, have been investigated using neutron diffraction (ND) and quasi-elastic neu tron scattering (QENS). For comparison, corresponding studies of pure PPO h ave also been performed. The diffraction data reveal large structural chang es which are induced by the dopant salt. The phenomena can be explained by local ordering of the chain segments around the solvated cations and by con traction of neighbouring chains via cationic cross links. The QENS results indicate that the segmental motions of the polymer chains, which have been considered to be of vital importance for the ionic mobility, slow down cons iderably when coordinated to cations. The results are discussed in relation to proposed models for the structure and the conductivity mechanism. (C) 1 998 Published by Elsevier Science B.V. All rights reserved.