STRUCTURE AND CONDUCTIVITY OF FAST ION-CONDUCTING BORATE GLASSES

We have performed neutron and X-ray diffraction experiments and made s tructural models using the reverse Monte-Carlo (RMC) simulation techni que. In order to obtain insights into the relation between the structu re and ionic conduction for the two fast ion-conducting glasses (AgI)( 0.6)(Ag2O-2B(2)O(3))(0.4) and LiCl-Li2O-2B(2)O(3). Large differences b etween the two glass structures are observed on an intermediate (4-20 Angstrom) length-scale. A first remarkably intense diffraction peak at the low momentum transfer of 0.8 Angstrom(-1) in S(Q) of the AgI-dope d glass is found to be due to inter-chain correlations of about 8-10 A ngstrom within the boron-oxygen network. The salt ions cross-link betw een the berate chains and are therefore located in pathways suitable f or ion conduction. The LiCl-doped glass, on the other hand, does not s how any low-Q peak in S(Q) or any characteristic intermediate distance .