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|Author(s):||Pratik Dholabhai; James B. Adams; Peter A. Crozier; Renu Sharma;|
|Title:||In Search of Enhanced Electrolyte Materials: A Case Study of Doubly Doped Ceria|
|Published:||October 28, 2011|
|Abstract:||Various compositions of gadolinium-praseodymium doubly doped ceria (GPDC) have been studied to appreciate 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 ≈ 0.2 mol fraction to 0.25 mol 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 the temperature ranging 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.|
|Citation:||Journal of Materials Chemistry|
|Pages:||pp. 18991 - 18997|
|Keywords:||Double doped Ceria, gadolinium, praseodymium, Kinetic Lattice Monte Carlo model|
|Research Areas:||Electronics, Modeling, Fuel Cells|
|PDF version:||Click here to retrieve PDF version of paper (885KB)|