Investigation of protonic conduction in Yb- and Y-doped barium zirconates

摘要

Barium zirconate ceramics doped with Y and Yb, BaM_xZr_(1-x)O_(3-α) (M = Yb, Y), are perovskite single phases and exhibit protonic conduction in moist nitrogen atmospheres at temperatures 500 < T (℃) < 1000. Samples with x = 0.10 have been investigated by ac and dc electrochemical techniques. Conductivities with Yb as dopant were larger, by a factor ≈ 10, than those with Y as dopant. Conductivities for Yb-doped samples (e.g. σ_b (750℃) ≈ 2X 10~(-4) S cm~(-1)) are lower than those reported for analogous cerates. Throughout the experimental temperature range, the apparent conductivity found in dc studies (summing resistances due to the electrolyte and electrode-electrolyte interfacial phenomena) was lower, by a temperature independent factor ≈ 2, than the conductivity determined by ac techniques.