Electronic Properties of Beta-Vanadium Bronzes Li xNa yV 2O 5 (0.23 ≤ x + y ≤ 0.37) Obtained by the Sol-Gel Process

• Published in: Journal of solid state chemistry Vol. 118; no. 1; pp. 10 - 19
• Main Authors: Pecquenard, B., Badot, J.C., Gourier, D., Baffier, N., Morineau, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1995
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1995.1304

Vanadium bronzes β-Li
x
Na
y
V
2O
5 (0.23 ≤
x +
y ≤ 0.37) have been synthesized by the sol-gel process. These compounds exhibit the monoclinic structure of compounds of the same composition prepared by solid state reaction, but they are obtained as thin layers with a highly preferred orientation. Studies of these compounds by magnetic susceptibility, electron paramagnetic resonance, and electrical conductivity measurements are presented. It is demonstrated from magnetic susceptibility and EPR linewidth that the bipolaron model describes accurately the electronic properties of the lithium and mixed lithium/sodium bronzes synthesized by the sol-gel process. Dc-conductivity measurements between 15 and 300 K show that the bronze conductivities are anisotropic and depend on the nature of the exchanged ion. More complete study on Li
0.23V
2O
5, including ac-conductivity and impedance measurements from 10 Hz to 10 GHz, gives a good correlation between all the experimental techniques described in this paper.