Electrical conductivity of H2V12-yWyO31+δ•nH2O and HxVxW1-xO3•nH2O

The electrical conductivity of H2V12 - yWyO31 + delta . nH(2)O (0 less than or equal to y less than or equal to 3) and HxVxW1 - xO3 . nH(2)O (x = 0, 0.08, 0.17, 0.25, 0.33) prepared by the sol-gel method was measured between 293 and 473 K at a relative humidity of 12%. Partial substitution of tungsten for vanadium or V5+ and H+ for tungsten was found to reduce the conductivity of the phases studied. The only exception is the x = 0.33 phase. Below 373 K, the activation energy of conduction is 0.22-0.29 eV in the amorphous phases (0 less than or equal to y less than or equal to 3; x = 0.25, 0.33) and 0.06-0.11 eV in the crystalline phases (x = 0, 0.08, 0.17). The possible mechanisms of electrical transport are discussed.