TY - JOUR
T1 - Oxygen ion conductivity in ceria-based electrolytes co-doped with samarium and gadolinium
AU - Coles-Aldridge, Alice V.
AU - Baker, Richard T.
N1 - The authors thank the University of St Andrews and the UK Engineering and Physical Sciences Research Council for the PhD studentship for AVC-A (grant code: EP/M506631/1). Electron microscopy was performed at the Electron Microscope Facility, University of St Andrews.
PY - 2020/4
Y1 - 2020/4
N2 - In a systematic study, two compositional series of ceria-based oxides, both co-doped with Sm and Gd, were synthesised using a low temperature method and evaluated as oxygen ion-conducting electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Series one, Ce1-2xSmxGdxO2-x, had equal concentrations of Sm and Gd but varying total dopant concentration. Series two, Ce0.825SmxGd0.175-xO1.9125, had a fixed total dopant concentration but the Sm:Gd concentration ratio was varied. The materials were characterised using scanning and transmission electron microscopy, inductively coupled plasma mass spectrometry and X-ray diffraction. Impedance spectra were recorded on dense pellets of these materials. From these, total, bulk and grain boundary conductivities and capacitances along with activation energies, pre-exponential constants and enthalpies of ion migration and defect association were obtained. These gave a detailed insight into the fundamental conduction processes in the materials. Ce0.825Sm0.0875Gd0.0875O1.9125 had the highest total ionic conductivity at temperatures of 550 °C and above and also demonstrated an enhanced conductivity with respect to its singly-doped parent compounds, Ce0.825Sm0.175O1.9125 and Ce0.825Gd0.175O1.9125, at 400 °C and above. This compares favourably with previously-reported values and has promising implications for the development of IT-SOFCs.
AB - In a systematic study, two compositional series of ceria-based oxides, both co-doped with Sm and Gd, were synthesised using a low temperature method and evaluated as oxygen ion-conducting electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Series one, Ce1-2xSmxGdxO2-x, had equal concentrations of Sm and Gd but varying total dopant concentration. Series two, Ce0.825SmxGd0.175-xO1.9125, had a fixed total dopant concentration but the Sm:Gd concentration ratio was varied. The materials were characterised using scanning and transmission electron microscopy, inductively coupled plasma mass spectrometry and X-ray diffraction. Impedance spectra were recorded on dense pellets of these materials. From these, total, bulk and grain boundary conductivities and capacitances along with activation energies, pre-exponential constants and enthalpies of ion migration and defect association were obtained. These gave a detailed insight into the fundamental conduction processes in the materials. Ce0.825Sm0.0875Gd0.0875O1.9125 had the highest total ionic conductivity at temperatures of 550 °C and above and also demonstrated an enhanced conductivity with respect to its singly-doped parent compounds, Ce0.825Sm0.175O1.9125 and Ce0.825Gd0.175O1.9125, at 400 °C and above. This compares favourably with previously-reported values and has promising implications for the development of IT-SOFCs.
KW - Activation energy
KW - Ceria
KW - Doping
KW - Electrolyte
KW - Ionic conductivity
KW - Solid oxide fuel cell
U2 - 10.1016/j.ssi.2020.115255
DO - 10.1016/j.ssi.2020.115255
M3 - Article
AN - SCOPUS:85079293394
SN - 0167-2738
VL - 347
JO - Solid State Ionics
JF - Solid State Ionics
M1 - 115255
ER -