Effect of synthesis atmosphere on the proton conductivity of Y-doped barium zirconate solid electrolytes

Abstract

a b s t r a c tYttrium-doped barium zirconate ceramic powders were synthesized by the oxidant peroxide method in air and under controlled atmosphere of nitrogen inside a glove box. The powders were characterized by thermogravimetry, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. After uniaxial cold isostatic pressing, green pellets were sintered at 1600°C for 4 h. The electrical conductivity behavior was accessed by electrochemical impedance spectroscopy. The results show that specimens synthesized under controlled atmosphere achieved higher electrical conductivity, two orders of magnitude higher than specimens prepared in laboratory air. The enhancement in electrochemical properties and increase in sintering ability is attributed to the less carbonate contamination as a result lower grain boundary density in the samples prepared under controlled atmosphere.

First principles calculations of the thermodynamic stability of Ba, Zr, and O vacancies in BaZrO3

“…43 The quantitative difference at higher temperature may be due to anharmonic effects, which are not considered in the present work. The difference between the ground state value of D f G BaZrO 3 and that for 300 K is À1.34 eV, which is in good agreement with the experimental values of À1.33 eV and À1.19 eV at 300 K. 43,44…”

Systematic Water Uptake Energetics of Yttrium-Doped Barium Zirconate—A High Resolution Thermochemical Study

“…Previous impedance spectroscopy and calorimetric studies on BZY x were performed on samples prepared by the OPM synthesis method in a controlled N 2 atmosphere. The results showed that the conductivity is maximum when lower density and cleaner grain boundaries are present in the microstructure; the dopant is still in a dilute regime in the BZ matrix, which occurs for Y concentrations up to 20%, and the temperature of the measurement is high enough to allow enhanced mobility of the charge carriers. , In the present work, despite the higher water uptake at a lower temperature, protons will preferably occupy trapping sites, which makes them mostly unavailable for the conduction process. , …”

“…The results showed that the conductivity is maximum when lower density and cleaner grain boundaries are present in the microstructure; the dopant is still in a dilute regime in the BZ matrix, which occurs for Y concentrations up to 20%, and the temperature of the measurement is high enough to allow enhanced mobility of the charge carriers. 22,26 In the present work, despite the higher water uptake at a lower temperature, protons will preferably occupy trapping sites, which makes them mostly unavailable for the conduction process. 21,22 Figure 5 shows the Arrhenius plot of the equilibrium constant (4) of the reaction of proton incorporation (2).…”

Examination of Morphological and Chemical Properties of Ni-BZY Anodes and their Influence upon Methane Reactivity and Electrochemical Performance of Protonic-Ceramic Fuel Cells

“…The hydrogentested cells withstood the test condition with little to no degradation. The slight decrease in the V-T curve towards the latter half of the 700 ℃ could be due to agglomeration of the anode cermet exacerbated at higher temperatures (25,30). Cells tested with NM and SRM experienced much greater rates of performance degradation.…”