Structure and conductivity of fast ion-conducting borate glasses

Abstract

We have performed neutron and X-ray diffraction experiments and made structural models using the reverse Monte-Carlo (RMC) simulation technique. In order to obtain insights into the relation between the structure and ionic conduction for the two fast ion-conducting glasses (AgI) 0.6 (Ag 2O2B 2O 3) 0.4 and LiClLi 2O2B 2O 3. Large differences between the two glass structures are observed on an intermediate (4–20 Å) length-scale. A first remarkably intense diffraction peak at the low momentum transfer of 0.8 Å −1 in S( Q) of the AgI-doped glass is found to be due to inter-chain correlations of about 8–10 Å within the boron-oxygen network. The salt ions cross-link between the borate chains and are therefore located in pathways suitable for ion conduction. The LiCl-doped glass, on the other hand, does not show any low- Q peak in S( Q) or any characteristic intermediate distance.