Mixed ionic-electronic conduction in sodium borate glasses with low V2O5 content

Abstract

The electrical resistivities and activation energies for electric conduction in glasses of the system Na2O-V2O5-B2O3 with V2O5<15 mol.%, have been measured. Two types of conductivities are postulated: ionic conductivity in the higher temperature region and electronic conductivity in the lower temperature region. V2O5 is assumed to be introduced into such glasses as a network former and also as a network modifier. It is deduced that the electronic conductivity in glasses with low concentrations of V2O5 is strongly affected by the concentration and the structural form of V2O5 in the glass. The dependence of the activation energy for electronic conduction on V2O5 content, for the glasses studied, is found to differ from that for glasses with high V2O5 content. It is assumed that the activation energy depends on the continuity of the V2O5 network.