Fig. 4: Structure and chemical stability of BaSn0.3Sc0.7O3−δ electrolyte.
From: Mitigating proton trapping in cubic perovskite oxides via ScO6 octahedral networks
a, HAADF-STEM image of dehydrated BaSn0.3Sc0.7O3−δ electrolyte and digital diffractogram (inset at bottom right). b, Time course of in situ powder X-ray diffraction patterns for hydrated BaSn0.3Sc0.7O3−δ under a concentrated and humidified CO2 stream. 2θ, the angle between the transmitted beam and reflected beam; pCO2, CO2 partial pressure. c, Amount of secondary BaSc2O4 plotted against exposure time to humidified CO2. The green, pink and red circles in a indicate the positions of the A sites (occupied by Ba), B sites (occupied by Sn and Sc) and O sites (occupied by O) in the perovskite-type structure, respectively. The time in b and c refers to the duration of the CO2-containing gas flow. Prior to the humidified CO2 flow, the powder sample was hydrated in an X-ray diffraction chamber for 9 h under a flowing humidified N2 stream with a water partial pressure (pH2O) of 0.02 atm. θ is the incident angle of X-ray. Colour in b represents the X-ray diffraction intensity. X-ray diffraction peak at 31.3° in b and c corresponds to the main peak of the BaSc2O4 phase. Assuming the degradation rate is proportional to the frequency of CO2 impacts on the material, and considering that the CO2 concentration during testing was 2,450 times that of ambient air (400 ppm), this accelerated stability test in b and c simulates over 100 years of exposure to ambient atmosphere at 300 °C.
