Mixed conduction in sodium vanadium bronze

The ionic and electronic conduction in α'-Na_xV₂O₅ prepared by the solid state reaction has been investigated. The electronic conductivity is nearly equal to the total conductivity and depends on the V⁴⁺ ion concentration. The Na⁺ ion conductivity was measured by a dc technique. The building up and decaying curves obtained at the transient polarization phenomena were analyzed by using a certain approximation for the steady state in order to save experimental time. The typical ionic conductivities were relatively low, namely 3×10^?6 and 2×10^?1 S cm?1 at 300°C for the samples of x=1.0 and 0.8, respectively which seemed to be dependent on the number of vacant Na⁺ ion sites.