Several double substitutions have been checked to compare the performances of these compounds with those of BICUVOX.10, which is used as a reference : (i) the introduction of two kinds of atoms in [V] sites (Cu-Ni, Cu-Zn, Ni-Zn, Cu-Mo); (ii) simultaneous substitution for [Bi] and [V] (Bi-Pb and V-Cu, Bi-Pb and V-Mo); (iii) substitution of Cu for [V] in the 2Bi2O3.V2O5 solid solution. In all cases the oxide anionic conductivity was not improved with respect to singly substituted V/Cu BICUVOX.10.