New silicon substituted BiMeVO : synthesis and study of structural properties in relation to ionic conductivity

Partial substitution of vanadium with silicon in the compound Bi₄V₂O₁₁, which belongs to the Aurivillius family, leads to the creation of a solid solution Bi₄V_2- Si O_11- (0 ≤ x ≤ 0.4). The compound with x = 0.1 turns out to be a monoclinic α-form of Bi₄V₂O₁₁, while the compounds with x = 0.2 and x = 0.3 are orthorhombic β-polymorphs, and the compound with x = 0.35 is of tetrahedral γ-polymorph. Electrochemical Impedance Spectroscopy has been used to measure the ionic conductivity of doped samples. The ceramic sample with x = 0.1 has the highest ionic conductivity values.