Ionic conductivity and boron anomaly in binary lithium borate melts

Abstract

A 4-electrode technique has been used to measure the ionic conductivity in the binary lithium borate system XLi2O-(100-X)B2O3 (X = 10–45 mol%) in a large temperature interval (300 °C-1100 °C). Above the glass transition temperature, the dc conductivity increases faster than in glassy state and it doesn't follow the Arrhenius law anymore. In the molten and the supercooled states, the conductivity data are well described by the phenomenological VFT law characteristic of a cooperative conduction mechanism. Moreover, at a given temperature, the conductivity increases with the Li2O content till 30 mol% of Li2O then slows down for additional Li2O oxide. This behavior, which is reported for the first time, could be associated to the signature of the “boron anomaly” in the molten state.