Lithium-based conducting glasses are promising candidates for electrolyte materials of thin-film batteries because they exhibits isotropic ionic conductivity. However, at room temperature most of such conducting glasses exhibit relatively low ionic conductivity values, in the range 10^-7 to 10^-8 S/m. In order to increase the conductivity, some specific additives have been used., one of them being vanadium. In a recent work on borate glasses, vanadium dopant at a level of several percent was used for this purpose [1-3]. It has been noticed that annealing of vanadium doped borate glass results in a change of physical properties [1]. This may suggest that vanadium enters specific crystallographic sites. In this work, a related material, vanadium-doped lithium silicate glass is studied. The glass was prepared by heating a mixture of quartz (SiO₂), lithium carbonate (Li₂CO₃) and vanadium pentoxide (V₂O₅) at a level of up to 5.5 weight percent at 1400 for 3 h and then cooled. As prepared glass was annealed for four hours at 550°C. This procedure gives virtually pure Li₂Si₂O₅ phase of orthorhombic Ccc2 space group [4] with vanadium present in the lattice and traces of impuity phases. The lattice parameters are found to vary isotropically with increasing vanadium content. We notice that the observed crystallisation is faster than that reported in literature for phosphate glasses [5].

References 

[1] N.A. El-Alaily, R.M. Mohamed, Effect of irradiation on differenial thermal properties and crystallization behavior of some lithium borate glasses, Nucl. Instrum. Meth. Phys. Res. B 179 (2001) 230-242

[2] Y.-I. Lee, J.-H. Lee, S.-H. Hong, Y. Park, Li-ion conductivity in Li₂O–B₂O₃–V₂O₅ glass system, Solid State Ionics 175 (2004) 687–690

[3] S.Y. Marzouk, N.A. Elalaily, F.M. Ezz-Eldin, W.M. Abd-Allah, Optical absorption of gamma-irradiated lithium-borate glasses doped with different transition metal oxides, Physica B 382 (2006) 340–351

[4] B.H.W.S. de Jong, H.T.J. Supér, A.L. Spek, N. Veldman, G. Nachtegaal, J.C. Fischer, Mixed alkali systems: Structure and ²⁹Si MASNMR of  Li₂Si₂O₅ and K₂Si₂O₅, Acta Cryst. B 54 (1998) 568-577 

[5] Y. Iqbal, W.E. Lee, D. Holland, P.F. James, Crystal nucleation in P₂O₅-doped lithium disilicate glasses, J. Mater. Sci. 34 (1999) 4399–4411