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Effect of Sm co-doping on structural, mechanical and electrical properties of Gd doped ceria solid electrolytes for intermediate temperature solid oxide fuel cells
- Source :
- International Journal of Hydrogen Energy. 45:29690-29704
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- Two series of samarium co-doped in 10 mol% Gd doped ceria Ce0.90Gd0.1O1.95(GDC10) formulated as Ce0.9-xSmxGd0.1O2-δ(CS) and Ce0.9Gd0.1-xSmxO2-δ(GS) (x = 0.0, 0.03, 0.05 0.10) were synthesized by glycine nitrate auto combustion method. The structural effects of Sm substitution in the GDC10 solid solution have been studied by X-ray diffraction (XRD) and Raman spectroscopy techniques. An increased lattice constant (5.407 A to 5.414 A) with decreasing crystallite size (28.6 nm 22.5 nm) was observed in both the Ce substituted by Sm (CS) and Gd substituted by Sm (GS) in GDC10 crystal system. The highest oxygen vacancy concentration ( V O ⋅ ⋅ = 2.65 × 1021 cm−3) was found for 10 mol % Sm and 10 mol % Gd doped ceria (Ce0.8 Sm0.1Gd0.1O1.90) composition (CS10) evaluated by spatial correlation model from Raman spectroscopy. The microhardness of the sintered pellets was investigated by Vickers hardness measurement. The highest fracture toughness was found to be 1.85 ± 0.27 MPa m1/2 for Ce substituted by 3 mol% Sm composition (CS3) among the overall compositions. The surface morphology and elemental composition of the CS and GS compositions were analyzed by FESEM. The morphology and composition of optimized electrolyte (CS10) was further analyzed by HRTEM and XPS respectively. AC impedance spectroscopy revealed that CS10 composition has an improved ionic conductivity (σ800 = 0.147 × 10−3 S‧cm−1) with significantly reduced activation energy (0.85 eV) in the temperature range of 673–1073 K under air atmosphere. A mechanism for conductivity enhancement by oxygen vacancy for CS compositions has been proposed. The effect of Sm as a secondary co-dopant in the GDC10 electrolyte was studied in detail to establish a candidate electrolyte material for operating solid oxide fuel cells in the intermediate temperature range (673–1073 K).
- Subjects :
- Materials science
Renewable Energy, Sustainability and the Environment
Analytical chemistry
Oxide
Energy Engineering and Power Technology
02 engineering and technology
Conductivity
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
0104 chemical sciences
chemistry.chemical_compound
symbols.namesake
Fuel Technology
X-ray photoelectron spectroscopy
chemistry
symbols
Fast ion conductor
Ionic conductivity
Crystallite
0210 nano-technology
Raman spectroscopy
Solid solution
Subjects
Details
- ISSN :
- 03603199
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- International Journal of Hydrogen Energy
- Accession number :
- edsair.doi...........c20b2e7b4d80dbc4a7e19d23e711ac68