High ionic conductivity of Lu2O3–TiO2 co-doped Bi2O3 ceramics

Abstract In this study, a promising electrolyte material Bi 0.76 Lu 0.16 Ti 0.08 O 1.5+ δ (abbreviated as ‘8T16LSB’) with high oxygen ion conductivity was obtained by co-doping with Lu 2 O 3 and TiO 2 into Bi 2 O 3 . The phase composition, microstructure, and conductivity of TLSB ceramics were respectively investigated by x-ray diffraction, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). XRD results exhibited that the sintered TLSB ceramics with an unchanged total doping concentration of 24 mol.% existed as a cubic fluorite structure. SEM results showed that the TLSB pellets were relatively dense. The relationship between temperature and conductivity showed that the 8T16LSB ceramic exhibited the highest conductivity of 0.56 S cm −1 at 700 °C, which was higher than the value of 0.37 S cm −1 for the representative single-doping Er 0.4 Bi 1.6 O 3 (abbreviated as ‘20ESB’). The results certified that the electrochemical performance of Bi 2 O 3 was promoted by the co-dopant of Lu 3+ and Ti 4+ .