Title : ( Molecular Dynamics Study of Complex Dopant Electrolyte Nd2–xHoxZr2O7: Structure, Conductivity, and Thermal Expansion )
Authors: mohammad razmkhah , Mohammad Taghi Hamed Mosavian , Fatemeh Moosavi ,
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Abstract
Nd2–xHoxZr2O7 is an ionic conductor for solid oxide fuel cell electrolytes. Temperature and dopant composition are two main factors that affect ionic conductivity of these groups of materials. Accordingly, Nd2–xHoxZr2O7 was studied in a wide range of temperature, 1,173–1,873 K, and dopant composition, x = 0.0–2.0, by molecular dynamics simulation. Arrhenius plots of ionic conductivity in region of low temperature declared that the maximum occurred at composition x = 0.6 (H6). Surprisingly, it was observed that complexity of dopant improved ionic conductivity of the electrolyte. Moreover, radial distribution function confirmed this result. Two types of anions were observed in the electrolyte, which were dynamic oxygen ions (DOIs) and static oxygen ions (SOIs). Mean square displacement (MSD) of DOIs was higher than SOIs and enhanced oxygen ionic conductivity. Migration barrier of Nd2–xHoxZr2O7 varied from 0.68 to 1.22 eV that was in the range of a good solid oxide electrolyte. Nd1.2Gd0.8Zr2O7 (G8) and Y0.2Zr0.9O2.1 (Y2) were simulated and their results of simulations were compared with H6. Order of ionic conductivity at low temperatures was H6 > Y2 > G8. Another important factor of electrolyte is thermal expansion. Thermal expansion of Nd2–xHoxZr2O7 was around a constant value in the studied temperature range.
Keywords
Complex Dopant;Diffusion Coefficient;Electrolyte;Ionic Conductivity;Membrane;Molecular Dynamics (MD) Simulation;Solid Oxide Fuel Cell (SOFC);Thermal Expansion
@article{paperid:1038474,
author = {Razmkhah, Mohammad and Hamed Mosavian, Mohammad Taghi and Moosavi, Fatemeh},
title = {Molecular Dynamics Study of Complex Dopant Electrolyte Nd2–xHoxZr2O7: Structure, Conductivity, and Thermal Expansion},
journal = {Fuel Cells},
year = {2013},
volume = {13},
number = {6},
month = {December},
issn = {1615-6846},
pages = {1048--1055},
numpages = {7},
keywords = {Complex Dopant;Diffusion Coefficient;Electrolyte;Ionic Conductivity;Membrane;Molecular Dynamics (MD) Simulation;Solid Oxide Fuel Cell (SOFC);Thermal Expansion},
}
%0 Journal Article
%T Molecular Dynamics Study of Complex Dopant Electrolyte Nd2–xHoxZr2O7: Structure, Conductivity, and Thermal Expansion
%A Razmkhah, Mohammad
%A Hamed Mosavian, Mohammad Taghi
%A Moosavi, Fatemeh
%J Fuel Cells
%@ 1615-6846
%D 2013
