TY - JOUR
T1 - In search of enhanced electrolyte materials
T2 - A case study of doubly doped ceria
AU - Dholabhai, Pratik P.
AU - Adams, James
AU - Crozier, Peter
AU - Sharma, Renu
PY - 2011/12/21
Y1 - 2011/12/21
N2 - Various compositions of gadolinium-praseodymium doubly doped ceria (GPDC) have been studied to elucidate the effect of two co-dopants in enhancing the ionic conductivity. A Kinetic Lattice Monte Carlo (KLMC) model of vacancy diffusion in GPDC has been developed, which uses activation energies obtained from DFT-calculations for vacancy migration in gadolinium-doped ceria (GDC) and praseodymium-doped ceria (PDC) as input. In order to identify the optimal composition of electrolyte materials for solid oxide fuel cells, three different classes of GPDC were studied; (i) Gd rich, (ii) Pr rich and (iii) equal Gd-Pr content. It is assumed that the Gd and Pr are 100% ionized to Gd3+ and Pr3+. KLMC simulations showed that GPDC compositions with ≈0.20 mole fraction to 0.25 mole fraction of total dopant content exhibited the maximum ionic conductivity. Among the three classes studied, Gd-rich GPDC is found to have the highest conductivity for temperatures ranging from 873 K to 1073 K. The optimal co-doped compositions were found to be slightly temperature dependent. Analysis of vacancy migration pathways for millions of jump events show that GPDC has a slightly higher number of next neighbor jumps, which seems to explain most of the reason why GPDC has a higher ionic conductivity than PDC or GDC. The current KLMC calculations present a novel approach to study doubly doped ceria, as so far the theoretical results for ceria-based materials have been limited to mono-doped ceria.
AB - Various compositions of gadolinium-praseodymium doubly doped ceria (GPDC) have been studied to elucidate the effect of two co-dopants in enhancing the ionic conductivity. A Kinetic Lattice Monte Carlo (KLMC) model of vacancy diffusion in GPDC has been developed, which uses activation energies obtained from DFT-calculations for vacancy migration in gadolinium-doped ceria (GDC) and praseodymium-doped ceria (PDC) as input. In order to identify the optimal composition of electrolyte materials for solid oxide fuel cells, three different classes of GPDC were studied; (i) Gd rich, (ii) Pr rich and (iii) equal Gd-Pr content. It is assumed that the Gd and Pr are 100% ionized to Gd3+ and Pr3+. KLMC simulations showed that GPDC compositions with ≈0.20 mole fraction to 0.25 mole fraction of total dopant content exhibited the maximum ionic conductivity. Among the three classes studied, Gd-rich GPDC is found to have the highest conductivity for temperatures ranging from 873 K to 1073 K. The optimal co-doped compositions were found to be slightly temperature dependent. Analysis of vacancy migration pathways for millions of jump events show that GPDC has a slightly higher number of next neighbor jumps, which seems to explain most of the reason why GPDC has a higher ionic conductivity than PDC or GDC. The current KLMC calculations present a novel approach to study doubly doped ceria, as so far the theoretical results for ceria-based materials have been limited to mono-doped ceria.
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U2 - 10.1039/c1jm14417k
DO - 10.1039/c1jm14417k
M3 - Article
AN - SCOPUS:81855185435
SN - 0959-9428
VL - 21
SP - 18991
EP - 18997
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
IS - 47
ER -