A Physicochemical Study of Sintered β-Li_xV₂O₅

Abstract

Sintered samples of Li_xV₂O₅ were prepared and the Li⁺ ion distribution in the β-phase was discussed. In the sample preparation by solid state reaction, LiVO₃ powder was used as the lithium source in place of Li₂O and Li₂CO₃ which had been used so far. The tablets made of mixed powders of LiVO₃, V₂O₅ and V₂O₃ were preheated at 560°C in nitrogen atmosphere. The samples thus obtained were ground, pressed into tablets and heated again at 560°C for 11h in nitrogen flow. The final products were identified to be β-phase by X-ray diffraction. The cell Li_xV₂O₅/LISICON/Li_0.25V₂O₅ was assembled to examine the sample of Li_xV₂O₅ physicochemically. The emf of the cell changed monotonously with the lithium content, which suggested that the one-phase β region was 0.22≤x>0.55 and the Li⁺ ions distributed at random on the possible cation sites, i.e. seven-coordinated, eight-coordinated and tetrahedral sites.