Influence of LiCl addition on the electrical conductivity of Li2O/B2O3/SiO2 glass system

Among the three eutectics in lithium borosilicate system, the composition 40Li2O/40B2O3/20SiO2 exhibits the highest conductivity. In the ternary lithium borosilicate glasses, the high lithium fraction, fLi, and low value of K (SiO2/B2O3) provide high ionic conductivity. The addition of LiCl to the optimum conducting eutectic composition gives a maximum in conductivity at 15 mol% LiCl. Due to the larger size of Cl− ions which go into the interstitial sites in the glass network, there is an expansion of lattice which broadens the path windows. This increases the jump probability and gives enhancement in the conductivity. For higher LiCl content (17.5 mol%), there are bottlenecks created that hinder the motion of lithium ions and reduce the conductivity. The lowering of Tg and density, ρ, with addition of LiCl in these glasses supports the interpretation of conductivity results.