Preparation And Properties Of CaZrO₃-based Solid Electrolyte

Since Iwahara et al. reported the proton conductivity of a perovskite type Y doped SrCeO3 in 1981, perovskite-type solid electrolytes have been used in a variety of electrochemical appliances as hydrogen sensors, fuel cells, hydrogen pump, etc. CaZrO3 has good chemical stability and sintering properties in perovskite type solid electrolytes, and is the preferred material for hydrogen sensors.In the work of the past, the conductivity of CaZr1-xInxO3-α (x=0.05,0.10,0.15) became higher with the increase of the doping content, but no one involved in the work of higher doping content. The conductivity of the measured values of different scholars were different for CaZr1-xScxO3-α(x=0.05,0.10,0.15). Electron hole plays an important role when the proton transports, but no one has studied the relationship between doping content and conductivity of hole. Therefore, we have researched the preparation of CaZrO3 by doping In and Sc. CaZr1-xInxO3-α(x=0.05,0.10,0.15,0.20,0.30) and CaZr1-xScxO3-α(x=0.05,0.10,0.15) were synthetized by solid state reaction, and the performance of the materials have been characterized; The influence of different doping content on the conductivity of samples has been explored, the ionic conductivity and hole conductivity under different oxygen partial pressure have been measured, the influence of different doping content on the ionic conductivity has been analyzed, and this thesis has discussed the change rule of hole conductivity under different oxygen partial pressure and different doping content.Following results were obtained by this study:1. The densities of the sintered samples of CaZr1-xMxO3-α(M=In, Sc) were higher than 97% of their theoretical densities. The SEM pictures demonstrated that the microstructure morphology of CaZr1-xMxO3-α(M=In, Sc) were compact.2. The conductivities of CaZr1-xMxO3-α(M=In, Sc) solid electrolytes were measured at 400～1400℃ in 0.490% H2/Argon. The result demonstrated that the conductivities of CaZr1-xInxO3-α(0.05≤x≤0.30) increased with the increase of the doping amount of In. When x=0.10 the conductivity of CaZr1-xScxO3-α(0.05≤x≤0.15) was highest, and higher than CaZr1-xInxO3-α.3. Arrhenius equation and conductive activation energy of CaZr1-xMxO3-α(M=In, Sc) at low temperature and high temperature were obtained through the data fitting and calculation. The conductivity activation was about 0.8eV when proton conductivity was dominant below 1000℃, and the conductivity activation was higher than 1.1 eV when oxygen ionic conductivity was dominant above 1000℃.4. The conductivity of CaZr1-xMxO3-α(M=In, Sc) was measured at 600～1000℃ under different oxygen partial pressure, and the relationship between hole conductivity and doping, oxygen partial pressure was obtained. The conductivity was highest when x=0.10 among CaZr1-xInxO3-α(0.05≤x≤0.30), and the conductivity was lowest when x=0.10 among CaZr1-xScxO3-α(0.05≤x≤0.15).5. Arrhenius equation and conductive activation energy of CaZr1-xMxO3-α(M=In, Sc) under different oxygen partial pressure were obtained through the analysis of experimental results, and found conductive activation increased with the decrease of oxygen partial pressure.