Effects of Sc doping on electrical conductivity of BaZrO3 protonic conductors

BaZr_1−x Sc _x O_3−0.5x (x=0.07, 0.10, 0.13, 0.16) powders were prepared by solid-state reaction method, and ZnO was used as sintering aid. Samples with different amount of ZnO additive were sintered at 1450 °C for 6 h in air. Single cubic perovskite phase proton conductors were obtained. Conductivity was measured by electrochemical workstation. It was shown that Sc doping could increase conductivity through enhancing the carrier concentration in the material, but excessive Sc content might decrease the carrier concentration because of its charge compensation. ZnO had an influence on carrier concentration and mobility and affected the electrical conductivity. 2 mol% ZnO and 13 mol% ScO_1.5 doped sample showed the highest DC conductivity of 3.6 × 10⁻³ S·cm⁻¹ tested at 800 °C in wet hydrogen atmosphere.