Vanadate glass is semiconductive with the electrical conductivity(σ) of 10
−7 - 10
−5 S cm
−1, which is caused by 3d electron(polaron) hopping from V
VI(or V
III) to V
V. Interestingly, a drastic increase of σ from 10
−5 to 10
0 S cm
−1 was observed when 20BaO·70V
2O
5·10Fe
2O
3 glass was isothermally annealed at around crystallization peak temperature(T
c) of 500°C, a quadrupole splitting(Δ) decreasing from 0.70 to 0.54mm s
−1. These results indicate that the increase in was in proportion to the decrease in the local distortion of FeO
4 tetrahedra as reflected in of the Mössbauer spectra. Based on the newly obtained results, the vanadate glass is expected to be a promising candidate as a cathode material of secondary battery. It is concluded that Mössbauer spectrometry is one of the essential techniques for the characterization of functional glasses and ceramics.
View full abstract