   BL19B2

2011A1853⇞ᩱ㟁ụసືᗘᇦ࡟࠾ࡅࡿ࣮࢞ࣞࢺ⣔㓟໬≀࢖࢜ࣥఏᑟయࡢᏳᐃ┦࡜ࡑࡢఏᑟᶵᵓ࡟㛵ࡍࡿ◊✲Investigation on stable phase and its conduction path of gallate-basedoxide- ion conductor at operating temperature range of fuel cell஭ᡭᮏᗣ, ໭ᮧᑦᩯ, 㮵ᓥᚭஓ, 㝮⏣ᗈᚿYasushi Idemoto, Naoto Kitamura, Tetsuya Kashima, Hiroshi Sumidaᮾி⌮⛉኱Ꮫ ⌮ᕤᏛ㒊 ᕤᴗ໬Ꮫ⛉Department of Pure and Applied Chemistry, Faculty of Science and Technology,
Tokyo University of Scienceᅛయ㓟໬≀ᙧ⇞ᩱ㟁ụࡢ㟁ゎ㉁ᮦᩱ࡜ࡋ࡚⏝࠸ࡽࢀ࡚࠸ࡿ୍㐃ࡢ࣮࢞ࣞࢺ⣔㓟໬≀࢖࢜ࣥఏᑟయ࡟╔┠ࡋࠊ≉࡟ᒙ≧ᵓ㐀ࢆ᭷ࡍࡿ LnSrGaO4 ࡜ LnSrGa3O7㸦Ln: ᕼᅵ㢮㸧ࢆẕయ࡜ࡍࡿ≀㉁࡟ࡘ
࠸࡚⤖ᬗ࣭㟁Ꮚᵓ㐀ゎᯒࢆ⾜ࡗࡓࠋࡑࡢ⤖ᯝࠊLnSrGa1-yMgyO4-Gࡣᕼᅵ㢮ࡢ✀㢮࡟౫ࡽࡎᒙ≧࣌ࣟࣈࢫ࢝࢖ࢺᆺᵓ㐀࡛࠶ࡾࠊGa-O 㛫ࡢᙉ࠸ඹ᭷⤖ྜᛶ࡟ࡼࡗ࡚ప࠸㓟໬≀࢖࢜ࣥఏᑟᛶࢆ♧ࡍࡇ࡜ࡀศ࠿ࡗࡓࠋࡲࡓࠊLnSrGa3O7 ࡛ࡣ Sr ࢆ Ln ࡛⨨᥮ࡍࡿࡇ࡜࡟ࡼࡾ᱁Ꮚ㛫࡟ఏᑟ㓟⣲ࡀྲྀࡾ㎸ࡲࢀࠊࡑࡢ఩⨨ࡣᕼᅵ㢮ࡢ✀㢮࡟౫Ꮡࡋ࡞࠸ࡇ࡜ࡀ♧၀ࡉࢀࡓࠋ࣮࣮࢟࣡ࢻ㸸 ⇞ᩱ㟁ụࠊ㓟໬≀࢖࢜ࣥఏᑟయࠊRietveld ゎᯒࠊ࣐࢟ࢩ࣐࣒࢚ࣥࢺࣟࣆ࣮ἲ㻔MEM㻕⫼ᬒ࡜◊✲┠ⓗ㸸 ᅛయ㓟໬≀ᙧ⇞ᩱ㟁ụ㻔SOFC㻕ࡣ⇞ᩱࡢ฼⏝ຠ⋡ࡀ㧗ࡃࠊ㧗౯࡞㈗㔠ᒓゐ፹ࢆᚲせ࡜ࡋ࡞࠸ࡓࡵࠊ᪂ࡓ࡞࢚ࢿࣝࢠ࣮※࡜ࡋ࡚ᬑཬࡀᮃࡲࢀ࡚࠸ࡿࠋࡋ࠿ࡋࠊࡑࡢࡓࡵ࡟ࡣ㟁ゎ㉁ᮦᩱ࡜ࡋ࡚㧗࠸࢖࢜ࣥఏᑟ⋡ࢆ♧ࡍ᪂つ࡞ᅛయ㟁ゎ㉁ࡢ㛤Ⓨࡀᚲせ୙ྍḞ࡛࠶ࡿࠋࡑࡢೃ⿵≀㉁ࡢ 1 ࡘ࡜ࡋ࡚ࠊప౯ᩘࡢ࢝ࢳ࢜ࣥࡢ⨨᥮࡟ࡼࡾ㓟⣲✵Ꮝࢆᑟධࡋࡓ La1-xSrxGa1-yMgyO3 ࡀὀ┠ࡉࢀ࡚࠸ࡿ[1]ࠋࡋ࠿ࡋࠊ
㏆ᖺࠊᅛయ㓟໬≀ᙧ⇞ᩱ㟁ụࡢసືᗘᇦ࡛ࡣᒙ≧ᵓ㐀ࢆࡶࡘ LaSrGaO4 ┦ࡸ LaSrGa3O7 ┦ࡀᏳᐃ┦࡛࠶ࡿ࡜ࡢሗ࿌ࡶ࠶ࡾࠊᐇ㝿࡟ྜᡂ᮲௳࡟ࡼࡗ࡚ࡣࡇࢀࡽࡀ୙⣧≀┦࡜ࡋ࡚⏕ᡂࡍࡿࡇ࡜ࡶከ࠸ࠋ୍᪉࡛ࠊࡇࢀࡽࡢ≀㉁ࡣᒙ≧ᵓ㐀ࢆ᭷ࡋ࡚࠾ࡾࠊࡑࢀ⮬㌟ࡶ㓟໬≀࢖࢜ࣥఏᑟᛶࢆ♧ࡍࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿ[2]ࠋࡇࡢࡼ࠺࡞⫼ᬒ࠿ࡽࠊࡇࢀࡽࡢ࣮࢞ࣞࢺ⣔ᒙ≧㓟໬≀࡟㛵ࡍࡿ▱ぢࢆᚓࡿࡇ࡜ࡣࢹࣂ࢖ࢫࢆタィࡍࡿ࠺࠼࡛ᴟࡵ࡚㔜せ࡜⪃࠼ࡽࢀࡿࡀࠊࡑࡢ⤖ᬗᵓ㐀࡜ᑟ㟁≉ᛶࡢ㛵ಀ࡟ࡘ࠸࡚ࡣ୙᫂࡞Ⅼࡀከ࠸ࠋ ࡑࡇ࡛ᮏ◊✲࡛ࡣࠊ୍㐃ࡢᒙ≧ᵓ㐀ࢆ᭷ࡍࡿ LnSrGaO4 ࠾ࡼࡧ LnSrGa3O7㸦Ln: ᕼᅵ㢮㸧ࢆ౯ᩘࡢ␗࡞ࡿ࢝ࢳ࡛࢜ࣥ⨨᥮ࡋࡓ≀㉁࠾ࡼࡧཧ↷ヨᩱ࡜ࡋ࡚ La1-xSrxGa1-yMgyO3-G࡟╔┠ࡋࡓࠋࡇࢀࡽࡢ≀㉁࡟ࡘ࠸࡚ᨺᑕග X ⥺ᅇᢡᐃ㸦ᐊ

㹼1000K㸧ࢆ⾜࠸ࠊRietveld࣭MEM ゎᯒ࡟ࡼࡾ⤖ᬗ࣭㟁Ꮚᵓ㐀ࢆ᫂ࡽ࠿࡟ࡍࡿࡇ࡜࡛ࠊᑟ㟁≉ᛶ࡜ࡢ┦㛵㛵ಀࢆ⪃ᐹࡋࡓࠋᐇ㦂㸸 LnSrGa1-yMgyO4-GࠊLn1+xSr1-xGa3O7+G࠾ࡼࡧ La1-xSrxGa1-yMgyO3-Gࢆ㏻ᖖࡢᅛ┦ἲ࡟ࡼࡾྜᡂࡋࡓࠋ
ᚓࡽࢀࡓヨᩱ࡟ࡘ࠸࡚ࠊ⢊ᮎ X ⥺ᅇᢡᐃ࡟ࡼࡿ┦ࡢྠᐃ࡜ࠊICP ࠶ࡿ࠸ࡣ EDX ࡟ࡼࡿ⤌ᡂศᯒࢆ⾜ࡗࡓࠋࡲࡓࠊྛ≀㉁ࡢᑟ㟁⋡ࢆ஺ὶ࢖ࣥࣆ࣮ࢲࣥࢫἲ࡛ᐃࡋࠊẕᵓ㐀ࡸ⤌ᡂࡀᑟ㟁≉ᛶ࡟୚࠼ࡿᙳ㡪ࢆ᳨ウࡋࡓࠋࡉࡽ࡟ࠊ⤖ᬗ࣭㟁Ꮚᵓ㐀ࢆヲ⣽࡟᳨ウࡍࡿࡓࡵࠊᨺᑕග X ⥺ᅇᢡࢹ࣮ࢱ
ࢆ⏝࠸ࡓ Rietveld ゎᯒ㻔RIETAN-FP[3]㻕࠾ࡼࡧ MEM ࡟ࡼࡿ㟁Ꮚᐦᗘศᕸゎᯒ㻔PRIMA[4]㻕ࢆ⾜ࡗࡓࠋᐃ࡟ࡣ⢊ᮎࢆ඘ሸࡋࡓ࢟ࣕࣆ࣮ࣛࣜࢆ⏝࠸ࠊ኱ᆺࢹࣂ࢖ࢩ࢙࣮࣓ࣛ࢝ࣛࢆ᭷ࡍࡿ BL19B2
㻔SPring-8㻕࡟ࡼࡾᐃἼ㛗 0.5 Å ࡛ᐇ㦂ࢆ⾜ࡗࡓࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸
LaSrGa1-yMgyO4-G࡟ࡘ࠸࡚ᑟ㟁≉ᛶࢆホ౯ࡋࡓ⤖ᯝࠊMg ࡢ⨨᥮㔞ࡀቑ࠼ࡿ࡟ࡘࢀ࡚ᑟ㟁⋡ࡣቑຍࡍࡿࡇ࡜ཬࡧ୺࡞ఏᑟ✀ࡣ㓟໬≀࢖࡛࢜ࣥ࠶ࡿࡇ࡜ࡀ᫂ࡽ࠿࡜࡞ࡗࡓࠋࡋ࠿ࡋࠊࡑࡢᑟ㟁⋡ࡣ
La1-xSrxGa1-yMgyO3-G⣔㓟໬≀࢖࢜ࣥఏᑟయࡼࡾࡶప࠸್࡛࠶ࡗࡓࠋࡲࡓࠊLnSrGaO4 ┦࡟ࡘ࠸࡚ࠊ
ᕼᅵ㢮ࡀ Pr ࡟࡞ࡿ࡜ᑟ㟁≉ᛶࡢྥୖࡀぢࡽࢀࡓࡀࠊࡇࢀࡣ㟁ᏊఏᑟᛶࡢⓎ⌧࡟ࡼࡿࡶࡢ࡛࠶ࡿࡇ
࡜ࡀศ࠿ࡗࡓࠋ୍᪉ࠊLa1+xSr1-xGa3O7+G࡟ࡘ࠸࡚ࡶ Sr ࢆ La ࡛⨨᥮ࡍࡿࡇ࡜࡟ࡼࡾᑟ㟁⋡ࡢቑຍࡀぢࡽࢀࡓࡀࠊࡇࢀࡣ᱁Ꮚ㛫㓟⣲ࡢᣑᩓ࡟ࡼࡿࡶࡢ࡜⪃࠼ࡽࢀࡿ[2]ࠋ࡞࠾ࠊLn1+xSr1-xGa3O7+G⣔࡛ࡣᕼᅵ㢮ࡢ✀㢮࡟౫ࡽࡎࠊྠᵝࡢᑟ㟁≉ᛶࢆ♧ࡋࡓࠋࡇࢀࡽࡢ≀㉁࡟ࡘ࠸࡚⤖ᬗ࣭㟁Ꮚᵓ㐀ࢆヲ⣽࡟᳨ウࡍࡿࡓࡵࠊᨺᑕග X ⥺ᅇᢡࢹ࣮ࢱࢆ⏝࠸ࡓRietveld࣭MEM ゎᯒࢆ⾜ࡗࡓࠋFig. 1 ࡟୍౛࡜ࡋ࡚ࠊLaSrGa0.97Mg0.03O4-Gࡢ Rietveld ゎᯒ⤖ᯝࢆ♧ࡍࠋ

Intensity / count15000010000050000

01020304050602T / degree
Fig. 1 Rietveld refinement pattern of LaSrGa0.97Mg0.03O4-G 㻔S. G.; I4/mmm㻕. Plus marks show observed
intensities, and a blue solid line represents calculated intensities. Vertical makes below the patterns
indicate the positions of allowed Bragg refractions. A curve at the bottom is the difference between
the observed and calculated intensities.
R-factors: Rwp=3.31 %, Rp=1.97 %, RI=2.33 %, RF=1.68 %Lattice constants: a=0.384283㻔2㻕 nm, c=1.268700㻔9㻕 nmࡇࡢᅗ࠿ࡽࡶศ࠿ࡿࡼ࠺࡟ࠊᕼᅵ㢮ࡢ✀㢮࡟౫ࡽࡎ LnSrGa1-yMgyO4-G ࡛ࡣ✵㛫⩌ I4/mmmࠊ
Ln1+xSrxGa3O7+G࡛ࡣ✵㛫⩌ P-421m ࢆ⏝࠸ࡿࡇ࡜࡟ࡼࡾࠊ⤖ᬗᵓ㐀ࢆ⢭ᐦ໬ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡗࡓࠋࡲࡓࠊMEM ゎᯒࢆ⾜ࡗࡓ⤖ᯝࠊᒙ≧ᵓ㐀ࢆ᭷ࡍࡿ LaSrGa0.97Mg0.03O4-G࡟࠾ࡅࡿ Ga-O 㛫ࡢඹ᭷⤖ྜᛶࡣ࣌ࣟࣈࢫ࢝࢖ࢺᆺᵓ㐀ࡢ La0.8Sr0.2Ga0.8Mg0.2O3-Gࡼࡾࡶᙉ࠸ࡇ࡜ࡀ♧၀ࡉࢀࡓࠋࡇࡢࡇ࡜
ࡀࠊ๓⪅ࡢ⣔࡟࠾࠸࡚㓟໬≀࢖࢜ࣥఏᑟᛶࡀప࠿ࡗࡓ୍ᅉ࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ
Fig. 2 ࡟ Ln1+xSr1-xGa3O7+G⣔≀㉁ࡢ୍౛࡜ࡋ࡚ Pr1.2Sr0.8Ga3O7+Gࡢ㟁Ꮚᐦᗘศᕸࢆ♧ࡍࠋ࡞࠾ࠊྠ≀㉁࡟࠾ࡅࡿ᱁Ꮚ㛫㓟⣲ࡢ఩⨨ࡣ୙࡛᫂࠶ࡿࡓࡵࠊࡑࡢᏑᅾࢆ௬ᐃࡏࡎ࡟ゎᯒࢆ⾜ࡗࡓࠋ(a)GaPr,SrO(b) 1×10-3 e·nm-3

GaInterstitial O

0 e·nm-3
Fig. 2 Electron density distribution of Pr1.2Sr0.8Ga3O7+G: 㻔a㻕 3D distribution 㻔The isosurface
level is 1.0 x 10-3 e·nm-3㻕 and 㻔b㻕㻌2D distribution of the 㻔001㻕 plane.
ࡑࡢ⤖ᯝࠊᅗ࡟♧ࡋࡓ᱁Ꮚ㛫఩⨨࡟㟁Ꮚᐦᗘࡀぢࡽࢀࡿࡇ࡜ࡀ᫂ࡽ࠿࡜࡞ࡗࡓࠋࡇࡢ఩⨨ࡣLa1+xSr1-xGa3O7+G࡟࠾࠸࡚᱁Ꮚ㛫㓟⣲ࡢᏑᅾࡀ♧၀ࡉࢀ࡚࠸ࡿ఩⨨࡜୍⮴ࡋ࡚࠾ࡾ[2]ࠊఏᑟࡍࡿ㓟⣲ࡢ఩⨨ࡣᕼᅵ㢮ࡢ✀㢮࡟౫Ꮡࡋ࡞࠸ࡇ࡜ࡀ♧၀ࡉࢀࡓࠋࡲࡓࠊ㓟⣲-㔠ᒓ㛫ࡢ⤖ྜ㛗࣭⤖ྜゅࡢኚ໬࠿ࡽࠊ᱁Ꮚ㛫㓟⣲ࡀᏑᅾࡍࡿ࡜⪃࠼ࡽࢀࡿ఩⨨ࡢ࿘㎶࡛ࡣࠊ✵㝽ࡢయ✚ࡀ኱ࡁࡃ࡞ࡗ࡚࠸ࡿࡇ࡜ࡀศ࠿ࡗࡓࠋ௒ᚋࡢㄢ㢟㸸 ௒ᚋࠊSOFC ࡢసືᗘᇦ࡛㛗᫬㛫ಖᣢࡋࡓヨᩱ࡟ࡘ࠸࡚ࡶ Rietveld࣭MEM ゎᯒࢆ⾜࠸ࠊ⤖ᬗ࣭㟁Ꮚᵓ㐀࡜Ᏻᐃ┦ࡢ㛵ಀ࡟ࡘ࠸࡚ࡶ᳨ウࡍࡿࠋࡲࡓࠊMPF 㻔MEM-based pattern fitting㻕 ゎᯒࢆ⾜࠺ࡇ࡜࡛ࠊࡼࡾ⢭ᗘࡢ㧗࠸⤖ᬗ࣭㟁Ꮚᵓ㐀ゎᯒࢆ⾜ࡗ࡚࠸ࡃࠋཧ⪃ᩥ⊩㸸[1] T. Ishihara et al., J. Am. Chem. Soc., 116, 3801 㻔1994㻕.
[2] X. Kuang et al., Nature Materials, 7, 498 㻔2008㻕.
[3] F. Izumi, et al., Solid State Phenom., 130, 15 㻔2007㻕.
[4] F. Izumi, et al. Mater. Sci. Forum., 378-381, 59 㻔2001㻕.