http://support.spring8.or.jp/Report_JSR/PDF_JSR_31A/2019A1626.pdf

2019A1626

BL14B2࣐ࢢࢿࢩ࣒࢘஧ḟ㟁ụ⏝ṇᴟᮦᩱ MgCo2-xMxO4䠄M: Ni, Mn䠅䠅ࡢ඘ᨺ㟁㐣⛬࡟࠾ࡅࡿ㟁Ⲵ⿵ൾᶵᵓ࡜ᒁᡤᵓ㐀ゎᯒ
Charge Compensation Mechanism and Local Structure Analysis of Mg
Rechargeable Cathode Material MgCo2-xMxO4䠄M: Ni, Mn䠅䠅during Chargeand Discharge Process஭ᡭᮏ ᗣ a, ໭ᮧ ᑦᩯ a, ▼⏣ ┤ဢ a, ཎ⏣ ᗣᏹ b, ➲ᕝ ဴஓ b Yasushi Idemotoa, Naoto Kitamuraa, Naoya Ishidaa, Yasuhiro Haradab, Tetsuya Sasakawabaᮾி⌮⛉኱, b䠄ᰴ䠅ᮾⰪaTokyo University of Science, bToshiba Co., Ltd.
᪂つࡢ࣐ࢢࢿࢩ࣒࢘஧ḟ㟁ụṇᴟᮦᩱ࡜ࡋ࡚ MgCo2-xMxO4䠄Ni, Mn䠅ࢆྜᡂࡋࡓࠋ඘ᨺ㟁㐣⛬࡟࠾ࡅࡿ㑄⛣㔠ᒓࡢ౯ᩘ࡜ᒁᡤᵓ㐀ࡢኚ໬ࢆ XAFS ࡟᳨࡚ウࡋࡓࠋXANES 㡿ᇦ࡟࠾࠸࡚㓟໬≧ែࢆࠊEXAFS 㡿ᇦࡼࡾᒁᡤᵓ㐀ࢆࡑࢀࡒࢀ᳨ウࡋࡓࠋࡑࡢ⤖ᯝࠊMn ࡢ XANES ࡼࡾࠊྜᡂࡉࢀࡓヨᩱ࡛ࡣ Mn4+࡛࠶ࡿࡀࠊᨺ㟁࡟ࡼࡗ࡚ Mn3+࡟㑏ඖࡉࢀࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋ࣮࣮࢟࣡ࢻ㸸 ࣐ࢢࢿࢩ࣒࢘஧ḟ㟁ụࠊṇᴟᮦᩱࠊXANESࠊEXAFS⫼ᬒ࡜◊✲┠ⓗ㸸ᵝࠎ࡞࣏࣮ࢱࣈࣝᶵჾࡢ㟁※࡜ࡋ࡚ከ⏝ࡉࢀࡿ⵳㟁ụࡢ୰࡛ࠊLi ࢖࢜ࣥ㟁ụࡣ௦⾲ⓗ࡞ࡶࡢ࡛࠶ࡿࡀࠊ㏆ᖺࠊࡑࡢ኱ᐜ㔞໬ࡀᚲせ࡜ࡉࢀ࡚࠸ࡿࠋ≉࡟ࠊ஧౯ࡢ㝧࢖࢜ࣥࢆ࢟ࣕࣜ࢔࡜ࡋࡓ Mg ஧ḟ㟁ụࡣࠊ኱ᆺ࡞㟁Ẽ⮬ື㌴ࡸᐃ⨨⏝㟁※࡟฼⏝ࡉࢀࡿࡇ࡜ࢆ᝿ᐃࡋ࡚◊✲ࡉࢀ࡚࠸ࡿࠋ㈇ᴟ࡟
㔠ᒓ Mg ࢆ⏝࠸ࡿ࡜ࠊࡑࡢ㈨※㔞ࡀ㇏ᐩ࡛Ᏻ౯࡛࠶ࡿࡇ࡜࡜ࠊయ✚࢚ࢿࣝࢠ࣮ᐦᗘ䠄3830 Ahydm-3䠅
ࡀ㔠ᒓ Li䠄2060 Ahydm-3䠅ࡼࡾࡶ஧ಸ㏆ࡃ㧗࠸ࡇ࡜࠿ࡽࠊ㔠ᒓ Mg ㈇ᴟࢆ⏝࠸ࡓ Mg ஧ḟ㟁ụࡣ኱ᐜ㔞ࡢḟୡ௦㟁ụ࡜ࡋ࡚ᮇᚅࡉࢀࡿࠋ᪤࡟ Mg ஧ḟ㟁ụࡢసືሗ࿌ࡣ࠸ࡃࡘ࠿࠶ࡿࡀࠊᐇ⏝໬࡟⮳ࡿࡓࡵ࡟ࡣࠊ㟁ゎᾮ࡜ṇᴟᮦᩱࡢ㛤Ⓨࡀᚲせ࡛࠶ࡿࠋࡋ࠿ࡋࠊ࠸ࡎࢀࡶ◊✲ࡀ┒ࢇ࡟ጞࡲࡿẁ㝵࡛࠶ࡾࠊṇᴟᮦᩱࡢೃ⿵࡜ࡉࢀࡿ≀㉁ࡣࢫࣆࢿࣝᆺᵓ㐀ࡢ MgCo2O4 [1]ࡀࡲࡎࡣ࠶ࡆࡽࢀࡿࠋᙜ◊✲ࢢ࣮ࣝࣉࡣࠊCo ࡟ Ni ࡸ Mn ࢆ⨨᥮ࡍࡿࡇ࡜ࡸࠊ୺ᡂศࢆ Co ࠿ࡽ V ࡬ኚ࠼ࡓ⣔ࢆ᪂ࡓ࡟ྜ
ᡂࡍࡿࡇ࡜࡟ࡼࡾ≉ᛶࡢྥୖ࡟ᡂຌࡋ࡚ࡁࡓࠋࡋ࠿ࡋࠊ᪤Ꮡࡢ㟁ゎᾮࡢ㟁఩❆ࡣ⊃࠸ࡓࡵࠊ
MgCo2O4 ࡣࠊ⌮ㄽᐜ㔞ࡼࡾࡶప࠸ᨺ㟁ᐜ㔞ࡋ࠿ᚓࡽࢀ࡚࠸࡞࠸ࠋᮏㄢ㢟࡛ࡣࠊࡇࢀࡲ࡛ࡢ᳨ウ࡛᭱ࡶ≉ᛶࡢ㧗࠸ MgCo1.5Mn0.5O4 ࡟ὀ┠ࡋ࡚ࠊMn ࢆ Ni ࡟⨨᥮ࡋࡓሙྜ࡜ࠊMn, Ni ࡢ⨨᥮㔞ࢆࢃࡎ࠿࡟ኚ࠼ࡓሙྜ࡜ࠊMn ࡜ Ni ࢆඹ⨨᥮ࡋࡓሙྜࡢ Co, Mn, Ni ࡢ㟁Ⲵ⿵ൾᶵᵓ࡟ࡘ࠸᳨࡚ウࢆ⾜࠺ࠋ┠ⓗ࡜ࡍࡿ໬Ꮫ⤌ᡂࡣࠊMgCo2-xMxO4䠄M: Mn, Ni䠅ࢆᇶ‽࡜ࡋ࡚ࠊx = 0.4, 0.5, 0.6 ࡢ᳨ウࢆ⾜࠺ࠋ᭦࡟ Mn, Ni ࢆඹ⨨᥮ࡋࡓ MgCo2-2xMnxNixO4 ࡶ◊✲ᑐ㇟࡜ࡋ᳨࡚ウࢆ⾜ࡗࡓࠋMg ࡀᤄධࡉࢀࡿሙྜࡢ⌮ㄽᐜ㔞ࡣࠊ⣙ 260 mAhyg-1 ࡛࠶ࡾࠊ⌧⾜ࡢ Li ࢖࢜ࣥ㟁ụṇᴟᮦᩱࡼࡾࡶ㧗࠸≉ᛶࡀᮇᚅࡉࢀࡿࠋḟୡ௦ࡢ஧ḟ㟁ụ࡬ࡢせồ࠿ࡽࠊLi ࢖࢜ࣥ㟁ụࡢ஧ಸࢆ┠ᣦࡋࡓ࢚ࢿࣝࢠ࣮ᐦᗘࢆ᭷ࡍࡿ Mg஧ḟ㟁ụṇᴟ㸫㈇ᴟᵓᡂࡀⓎぢࡉࢀࢀࡤࠊపࢥࢫࢺ࠿ࡘᏳ඲ᛶࡢ㧗࠸ḟୡ௦⵳㟁ụ࡜ࡋ࡚᭷ᮃどࡉࢀࡿࠋୖグࡢࡼ࠺࡞⫼ᬒ࠿ࡽᙜࢢ࣮ࣝࣉࡣࡇࢀࡲ࡛࡟ࢫࣆࢿࣝᆺ MgCo2-xMxO4䠄M: Ni, Mn䠅ࢆྜᡂࡋࠊࡑࡢ Mg ஧ḟ㟁ụ≉ᛶ࡜⤖ᬗᵓ㐀ࡢ㛵ಀࢆ᫂ࡽ࠿࡟ࡋ࡚ࡁࡓ [2]ࠋࡉࡽ࡟ࢫࣆࢿࣝᆺ Mg1+x
䠄V,Ni䠅2-xO4 ࢆṇᴟ࡜ࡋࡓ Mg ஧ḟ㟁ụసື࡟క࠺ Mg ࡢᤄධ࣭⬺㞳࡟ᑐࡋ࡚ XAFS ࡜ᨺᑕග X ⥺ᅇᢡࢆ⏝࠸࡚౯ᩘ࡜ᖹᆒ࣭ᒁᡤᵓ㐀ࡢ᳨ウࢆ⾜ࡗࡓ [3]ࠋᮏㄢ㢟ࡣࠊᑐ㇟࡜ࡍࡿ MgCo2-xMxO4 䠄M:Ni, Mn䠅࡟࠾࠸࡚ࠊ⤌ᡂࢆ⢭ᐦ࡟ไᚚࡍࡿࡇ࡜࡛㑄⛣㔠ᒓࡀ඘ᨺ㟁࡟ཬࡰࡍᙳ㡪ࢆ᫂ࡽ࠿࡟ࡍࡿࠋ
ࡲࡓࠊNi ࡜ Mn ࡢඹ⨨᥮ࡣᮍࡔሗ࿌ࡉࢀ࡚࠾ࡽࡎࠊ᪂ࡓ࡞ヨࡳ࡜ࡋ࡚ྜᡂࢆ⾜࠸ࠊ᭱㐺࡞㑄⛣㔠ᒓ⤌ᡂ࡟㛵ࡍࡿ▱ぢࢆᚓࡿࡇ࡜ࢆ┠ⓗ࡜ࡍࡿࠋᐇ㦂㸸ᮏㄢ㢟࡛ࡣࠊࢫࣆࢿࣝᆺ MgCo2-xMxO4䠄M: Ni, Mn䠅࡟ᑐࡋ࡚ M ࡢ⨨᥮㔞 x ࡢ␗࡞ࡿヨᩱ࡜ࠊMn,Ni ࢆඹ⨨᥮ࡋࡓヨᩱ MgCo2-2xNixMnxO4 ࢆ㏫ඹỿἲࢆ⤒⏤ࡋࡓᅛ┦ἲ࡟ࡼࡾྜᡂࡋ࡚ ᐃᑐ㇟ヨ䠉㻞㻣䠉ᩱ࡜ࡋࡓࠋX ⥺྾཰ᚤ⣽ᵓ㐀䠄XAFS䠅ࡣࠊMn, Ni, Co ࡢ K ྾཰➃࡟ࡘ࠸࡚ࠊSi䠄111䠅ࣔࣀࢡ࣓࣮ࣟࢱ࣮࡛㏱㐣ἲ࡟ࡼࡾᐇ᪋ࡋࡓࠋྜᡂࡉࢀࡓヨᩱ࡟ຍ࠼࡚ࠊྛヨᩱࡢึᅇᨺ㟁㐣⛬࡜‶඘㟁≧ែ࡟ㄪᩚࡋࡓ㟁ᴟヨᩱࡶ ᐃࡋࡓࠋ ᐃࡋࡓྛヨᩱ࡟ᑐࡋ࡚ࠊCo, Ni, Mn ࡢ XANES ࢫ࣌ࢡࢺࣝ࡜EXAFS ࢫ࣌ࢡࢺࣝࢆྲྀᚓࡋ࡚ࠊ㑄⛣㔠ᒓࡢ㓟໬≧ែ࡜ᒁᡤᵓ㐀ࢆㄪᰝࡋ࡚ࠊ඘ᨺ㟁࡟క࠺ኚ໬ࢆ᳨ウࡋࡓࠋ≉࡟ࠊ඘ᨺ㟁㐣⛬࡛⏕ࡌࡿ Mg ࡢᤄධ࣭⬺㞳࡟క࠺ྛ㑄⛣㔠ᒓࡢ㓟໬࣭㑏ඖࢆ XANES࡛ࠊᒁᡤᵓ㐀ࢆ EXAFS ࡛⢭ᰝࡍࡿࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸ྜᡂࡉࢀࡓヨᩱࡣࠊ࠸ࡎࢀࡶ XRD ࡟ࡼࡗ࡚íࢫࣆࢿࣝᆺᵓ㐀䠄✵㛫⩌ )G-3P䠅࡟ᖐᒓࡉࢀࡓࠋ
ICP-AES ࡢ⤖ᯝࠊ㔠ᒓ⤌ᡂẚࡣᴫࡡ௙㎸ࡳ⤌ᡂ㏻ࡾ࡟ไᚚࡉࢀࡓࡀࠊMg ࡢ⤌ᡂẚࡣ௙㎸ࡳࡼࡾࡶᑡ࡞࠸ഴྥࡀᚓࡽࢀࠊヨᩱ࡟ࡼࡗ࡚␗࡞ࡿ
ࡇ࡜ࡀศ࠿ࡗࡓࠋ୕ᴟᘧࢭࣝࢆ⏝࠸ࡓ Mg ஧ḟ㟁ụṇᴟ≉ᛶࢆホ౯ࡋࡓ⤖ᯝࠊ࠸ࡎࢀࡢヨᩱࡶ඘㟁ࡼࡾࡶᨺ㟁ࡢᐜ㔞ࡀ኱ࡁࡃࠊᨺ㟁࡟క࠺Mg ࡢᤄධࡀඃ఩࡞㟁Ẽ໬Ꮫ≉ᛶࢆ♧ࡋࡓࠋࡋ
Fig. 1 XANES spectra at Ni .-edge of MgCo2࠿ࡋࠊ2 ࢧ࢖ࢡࣝ௨㝆ࡣึᅇᨺ㟁ᐜ㔞ࡼࡾࡶ㢧
2xNixMnxO4 䠄 MCNMO 䠅 and their firstⴭ࡟ప࠸ࡓࡵࠊึᅇᨺ㟁࡟క࠸ᤄධࡉࢀࡓ Mgchargeor discharge state and MgCo2-xNixO4
ࡣࠊ୍㒊୙ྍ㏫࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ⪏㓟໬ᛶ
䠄MCN䠅.
ࡢ㧗࠸㟁ゎᾮ࡟ࡼࡗ࡚ࠊ㧗㟁఩ࡲ࡛඘㟁࡛ࡁࢀࡤ Mg ࡢ⬺㞳ࡀᮇᚅࡉࢀࠊࡑࡢࡼ࠺࡞㟁ゎᾮࡀⓎぢࡉࢀࢀࡤ Mg ஧ḟṇᴟᮦᩱ࡜ࡋ࡚᭷ᮃ࡛
࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ୍᪉ࠊMgCo2-2xNixMnxO4 ࡣࠊNi ࡜ Mn ࢆ Co ࡟ᑐࡋ࡚ඹ⨨᥮ࡉࢀࡓヨᩱ࡛࠶ࡿࠋ⨨᥮㔞 x ࡀ኱ࡁ࠸࡯࡝ 2 ࢧ࢖ࢡࣝ௨㝆ࡢࢡ࣮ࣟࣥຠ⋡ࡀ㧗ࡃࠊࡑࡢ⤖ᯝ࡜ࡋ࡚ᨺ㟁ᐜ㔞ࡀྥୖࡍࡿࡇ࡜ࡀศ࠿ࡗࡓࠋඹ⨨᥮㔞 x = 0.4
ࡢሙྜ࡟᭱ࡶ㧗࠸ Mg ஧ḟ㟁ụṇᴟ≉ᛶࢆ♧ࡋࡓࠋ ྜᡂࡉࢀࡓヨᩱ࡟ࡘ࠸࡚ XAFS ᐃࢆ⾜ࡗFig. 2 Fourier transformed EXAFS spectra of Mn
ࡓࠋFig. 1 ࡟ྜᡂࡉࢀࡓヨᩱࡢ Ni K ྾཰➃ࡢin MgCo2-2xNixMnxO4䠄MCNMO䠅and their
XANES ࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋᶆ‽ヨᩱ࡜ࡋ࡚ࠊ
first charge or discharge state.
NiO, LiNiO2 ࡢࢫ࡮ࢡࢺࣝࡶ♧ࡍࠋྜᡂࡉࢀࡓ
ヨᩱࡢ Ni ࡣ 2 ౯࡜ 3 ౯ࡢ㛫ࢆ♧ࡋࡓࠋ඘㟁ᚋ࡛ࡣ 3 ౯ࡲ࡛㓟໬ࡉࢀࡎࠊᨺ㟁ᚋ࡟ࢃࡎ࠿࡟㑏ඖࡉࢀ࡚ 2 ౯࡟㏆࡙ࡃࡇ࡜ࡀศ࠿ࡗࡓࠋNi ࡢ㓟໬㑏ඖࢆ฼⏝ࡍࡿࡓࡵ࡟ࡣࠊ㟁ゎᾮࡢ㓟໬⪏ᛶࢆࡼࡾ㧗ࡃࡍࡿᚲせࡀ࠶ࡿࠋ࡞࠾ࠊMn ࡜ Co ࡢ XANES ࢫ࣌ࢡࢺࣝ࠿ࡽࠊྜᡂࡉࢀࡓヨᩱࡢ Mn ࡣ 4 ౯ࠊCo ࡣ 3 ౯ᮍ‶ࢆ♧ࡋࡓࠋ࠸ࡎࢀࡶ඘㟁ᚋ࡟࡯࡜ࢇ࡝㓟໬ࡉࢀ࡚࠾ࡽࡎࠊᨺ㟁ᚋ Mn ࡣ 3 ౯ࠊCo ࡣ2 ౯ࡲ࡛㑏ඖࡉࢀࡓࡇ࡜ࡀศ࠿ࡗࡓࠋMn ࡢ EXAFS ࢆࣇ࣮࢚ࣜኚ᥮ࡋࡓࢫ࣌ࢡࢺࣝࢆ Fig. 2 ࡟♧ࡍࠋྜᡂࡉࢀࡓヨᩱࡢ Mn ࡣ 4 ౯࡛࠶ࡗࡓࡓࡵࠊ඘㟁ᚋ࡟ኚ໬ࡣᑡ࡞ࡃࠊᨺ㟁ᚋ࡟ EXAFS ࢫ࣌ࢡࢺࣝࡢ➨୍㏆᥋ࣆ࣮ࢡࡀ㢧ⴭ࡟పୗࡋࡓࠋࡇࢀࡣ Mn-O ࡟ṍࡳࡀ⏕ࡌࡓྍ⬟ᛶࢆ♧၀ࡋ࡚࠾ࡾࠊ
ᨺ㟁࡟ࡼࡗ࡚ Mn4+ࡀ Mn3+࡟㑏ඖࡉࢀ࡚ࠊ࣮ࣖࣥࢸ࣮ࣛຠᯝࡀ⾲ࢀࡓ࡜ゎ㔘ࡉࢀࡿࠋ௒ᚋࡢㄢ㢟㸸௒ᅇࠊXANES ࠿ࡽุ᫂ࡋࡓࡼ࠺࡟ࠊNi ࡜ Co ࡀ඘㟁࡟ࡼࡗ࡚㓟໬ࡉࢀ࡚࠸࡞࠸ࡓࡵࠊ㓟໬⪏ᛶࡢ㧗࠸㟁ゎᾮࢆ⏝࠸࡚඘ᨺ㟁ヨ㦂ࢆ⾜࠸ࠊᒁᡤᵓ㐀ኚ໬ࢆゎ᫂ࡋ࡚࠸ࡃࠋཧ⪃ᩥ⊩㸸[1] T. Ichitsubo HWDO, -0DWHU&KHP, 21, 11764 䠄2011㻕
[2] ஭ᡭᮏ ᗣ ௚ࠊᖹᡂ 29 ᖺᗘ 㔜Ⅼ⏘ᴗ฼⏝ㄢ㢟ሗ࿌᭩䠄2017A㻕, p. 64-65, 2017A1578.
[3] ஭ᡭᮏ ᗣ ௚ࠊ➨ 59 ᅇ㟁ụウㄽ఍ㅮ₇せ᪨㞟, pp. 375 䠄2018㻕䠉㻞㻤䠉