| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2013: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2012: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2011: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Research Abstract |
Theoretical calculations based on density functional theory have been systematically performed to compute the point defect formation behavior of BaZrO3. Thermal equilibrium defect concentrations are evaluated including defect association models. Our calculations have quantitatively revealed that stoichiometry strongly affects defect formation behavior in BaZrO3. Ba-rich condition is necessary for synthesizing proton conductive BaZrO3. If phase equilibrium condition of BaZrO3 samples changes to opposite Zr-rich side, hydration reaction is suppressed by dopants substituted for Ba sites. Hydration of oxide vacancy by water molecules associated with temperature decreasing is successfully reproduced by calculations based on DFT and thermodynamics. Calculations of association energy show that protons are mostly bound with trivalent acceptor dopants at lower temperature conditions. In order to improve proton conductivity in oxides, dopants showing low association energy need to be chosen.
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