gsbNXX üzûªõ¨æÑæê´vZÉæé`ECIñdrÌ[d@\ðÍvÛº [®ïÐúYA[N §237_0061 ¡{êsÄ¬ 1 Ôn¡äpl®ïÐúYA[N §237_0061 ¡{êsÄ¬ 1 Ônv |`ECIñdr³ÉÌ[dßöiLi E£½jÌhbNX½ðÍÌ½ßCL­edge XANES, K­edge
in­situ XANES ªèCÈçÑÉæê´vZÉæé XANES XyNgV~ [VðsÁ½áðÐî·éB
Li2MnO3 ÅÍCMn K­edge XANES Ì`óÏ»ªFßçêCMn Ì[d½ÖÌñ^ª¦´³êéªCÀÛÍ MnÌ¿Ï»ÍÙÆñÇÈ­CO ª½Éñ^µÄ¢é±Æª¾ç©ÆÈÁ½B±ÌÊÍCXANES `óªå«­Ï»µÄà¿ªÏ»µÈ¢êàèÓðv·é±Æð¦´µÄ¢éB±Ìæ¤ÈIÈðÍÍC¡GÈ\¢ðà¿¡GÈdC»w®ð¦·eÊÞ¿ÌðÍÉLøÅ®ðc¬·é±ÆÅj^[·é±ÆªÅ«éB

1. Í¶ßÉ

±¤µ½[údÉº¤ Li CIâdqÌ®«ðÏª·q±£ÌåC[dÔÌZkCdr·õ½»Æ¢Á½dC©®ÔÌ³çÈéÖ«üãÌ½ßC»ÌL[eNmW[ÅéÆl¦çêéBéè@ð Table 1 ÉÜÆß½BLi CIÌ®«ðÏª·é
è@ÆµÄÍCNMRC«qñÜ@ªèC¯ÊÌu·é`ECIñdrÌ«\üãÖúÒªÜÁÄ¢éB1991NÉ\j[ªÀp»µ½oC
pÌ`ECIñdrÍCJ[{ÆwóRog_»¨ªdÉ¨¿ÆµÄgp³êÄ¢éªC³çdC©
®ÔÌq±£ðÁ³¹é½ßCVRâ Li ßènÆÄÎêéÅ«éÀè`Eð½­Å«éVÞ¿ªoêµnßÄ¢éB±¤¢Á½VÞ¿ÍC»Ì\¢ª¡G
Ådr½@\à¡GÅéB»Ì½ßÞ¿ÉfoCXÌÝvÉÍCdr½ÌÚ×ðc¬·é±ÆªK{ÆÈÁÄ¢éB{eÅÍCÅVÌdr½ðÍû@ÌÐÆÂÆµÄCúËõÆæê´vZð¹pµdq\¢ÉÚµ½è@ðÐîµ½¢B`ECIñdrÍCÉC³ÉCdðtCZp[^©ç\¬³êÄ¢éiFig. 1jBdC©®ÔÌq±Â\£É·éudreÊvÍC³ÉCÉ¨¿ðÜ

Fig. 1(Color online) Conguration of a lithium ion secondary bat­tery.

Table 1

Experimental methods for analyzing transport of Li ionsand electrons.

ÞdÉÉæèÜêéÂ®È Li CIÌÊÅÜéB·Èí¿C[dÅ®­uÂ®v`Eª½¢ÙÇCeÊÌÞ¿Æ¢¤±ÆªÅ«éBLi CIÌÚ®ªN±éÆC»Ìd×âðs¤½ßÉdqàÚ®·éB³ÉÞ¿ÅÍC\¬³fCÜ½ÍC_fÉÜÜêédqªúo³ê

ðÍè@éB©ûðÏ¦êÎCJÚà®â_fÉÂ®Èdqª½¢j¥C¤ÂÙÇeÊÌÞ¿Æ¾¤±ÆàÅ«éB`ECIñ«qñÜ@LiLi ÌTCgIÊCgUW¨àÉ Li \¢ðÍiLi â O ÌTCgðÁèjdCvªdq

drÍC[údðJèÔ·ÆXÉeÊª¸ÁÄµÜ¤ò»»ÛªN«éªC±êàÂ®È Li CIâdqÌÚÎX üzûªõ@ dqÛÁ¥

I_V Á«CdqÌæÊsÂ
³fIðLCdqÌN¹ðèÂúËõ March 2015 Vol.28 No.2 43(C) 2015 The Japanese Society for Synchrotron Radiation ResearchÈÇÉæèTCgIÊðs¢ÈªçC»ÌóÔðÏª·ésÁ½drZððÌµCôòãÉgXt@[xbZ±ÆªÅ«éBêûCdqÌ®«ðÏª·éû@ÆµÄðp¢Ä^óóÔÌªèºÉ±üµ½BÍCêÊIÈ[údÌdCÁ«vªªéB\¢ðÍÆdC»w®ðgÝí¹é±ÆÅåÜ©Èóµðmé±ÆÍÂ\ÅéB½¾µCêUñHÉæèo³ê½dq

2.3

æê´vZ¨æÑ XANES V~

[Vdq\¢vZÉp¢½\¢ð Fig. 2 É¦·BLi ð£E³ÍCàÆàÆÇÌ³fÉR·é©Æ¢¤îñª¸íêÄ¹½\¢ÅÍCúlÆµÄ[gxgðÍ©ç¾çê¢éÌÅCÇÌ³fªLøÉ[údÉñ^µÄ¢é©ð»½\¢p[^ðp¢\¢ÅK»ðÀ{µ½B¡ñÌvf·é±Æªïµ¢BúËõðpµ½ X üzûªõ@Z Å Í Li Ê Í LixMnO3 Ì x  2.0, 1.5, 1.0 Æ µ VASP1,2)

Í³fIð«ªéÌÅCÇÌ³fÌdqª[údÉÖAÉæé\¢ÅK»ÍCPBE ð·ÖÖðp¢3)CJbgµÄ¢é©²×éÉÍsªæ­C[údJjYðð

It700 eV, K _ð 7~4~7 ÆµÄCLi Æ O Í 1s, Mn ÍÍÅ«éè@ÆµÄúÒ³êÄ¢éB2p ÜÅÌ[|eVÖðp¢ÄvZµ½BK­edge XANES ÌV~[VÍ WIEN2k4,5)Éæ

Ì¿Ï»ðj^[·é±ÆÅCLi Ì}üE£ÊCdèÀ{µ½BXANES V~[VÍ 1s O¹É core­qÌÚ®Êðè·é±ÆªÅ«éBêÊIÉÍChole ð±üµC}tBeB¼að Li, O, Mn ð»ê

XANES ÌVtg©ç¿Ï»Êª©ÏàêéªC¯ê³¼êC1.90, 1.65, 1.85 Bohr ÆµCRkmax 6.0 Ry ÉÄvfª¡TCgÉ¶Ýµ½èC¡Ì¬¨Å

ZðÀ{µ½Bcore­hole Ìe¿ª³ÉÞ¿Ì]¿ÉÖµÄÍCJÚà®Ì¿Ï»C_féêCÏ»Êðè«IÉ]¿·é±ÆÍïµ¢êª éBÜ½CXANES Ì`óÍC¿ÌÝÈç¸ÇIÈ\¢Ï»Éº¤d×ªzÌe¿à­­ó¯é½ßCK¸µà¿Ï»Ìé½ß 2~1~2 ÌX[pZðp¢ÄvZðÀ{µ½BL­edge XANES ÌV~[VÍrìçÉæÁÄJ­³ê½ DFT­CI R[hÉæé multiplet vZÉÄÀ{Ýð½fµÄ¢éí¯ÅàÈ¢B±Ìæ¤ÈÛèÖÎ·é½ßCJÚà® K­edge ¨æÑ L­edge XANES ªèÆæê´vZÉæé K­edge ¨æÑ L­edge XANES V~

[VÌ¡IÈpðñÄµÄ¢éBæê´vZðp¢Ä K­edge XANES V~

[Vðs¤±ÆÉæèC¡GÈ®ð¦·

XANES `óÏ»©çC¿Ï»ðæè³mÉÇÝæé±ÆªÂ\ÉÈéBÜ½Cdr½ÉÖ^·é 3d O¹ð¼ÚIÉÏª·é L­edge XANES XyNg©çÍC÷Ê
Ì 3d dqO¹ÌóÔÏ»ðÇÝæé±ÆªÅ«éB{eÅÍC±ÌIÈðÍð Li ßè³ÉÞ¿ÌêÞÅé

Li2MnO3 ÖKpµ½áðSÉÐî·éB2. À±û@2.1

±drZCÌ_f³ÉÞ¿ Li2MnO3 ÍCLi2CO3 Æ MnO2 ð500µÍCÅ24ÔÄ¬µ½àÌðp¢½B³ÉÞ²ðoC_[C±dÜÆ¬ûµÄX[ðìèCAl WdãÉhzµCdÉðì»µ½BLi à®ðÎÉC1M
LiPF6/ECFDEC3F7 ðdðtÆµCn[t^~l[gZðgÝã°CXANES ÌªèÉp¢½B

2.2

XANES ªè

Mn K­edge XANES ªèÍ SPring­8 Ì BL16B2 É¨¢ÄC§ß@ÅÀ{µ½B0.05C Ì[gÉÄ[dÉ in­situ ªèðÀ{µ½BMn L­edge XANES ¨æÑ O K­edge XANES ÍC§½
Ùåw SR Z^[ BL­2 ÉÄCdqûÊ@ÉÄåCñI ex­situ ªèÉæèÀ{µ½BèeÊÜÅ[dúdð44  úËõ March 2015 Vol.28 No.2Fig. 2(Color online) Crystal structure of LixMnO3. (x2.0, 1.5,1.0)9)

gsbNX ¡ X üzûªõ¨æÑæê´vZÉæé`ECIñdrÌ[d@\ðÍµ½6)B±ÌvZè@ÍCÎÌ«â d O¹ÌdqÌÙÈvZµ½ÊÍC¾ç©ÉXyNgªÙÈÁÄ¨èC±éJÚà®ÌvZÉ±êÜÅp³êÄ¢é7,8)BÌÊ©çà Mn ª 4 ¿ÌÜÜÅéÆl¦çêéB

Mn ªå½é½íÅÈ¢Æ·éÆC_fª[údÉñ^µÄ¢éÂ\«ª¢BLi Ì£EÉæéhbNX½3. ÊíÌÁèÌ½ßC_fÌ K­edge XANES ðªèµ½

Mn K­edge in­situ XANES ª è  Ê ð Fig. 3 É ¦ · BÊð Fig. 7 É¦·BA Ìs[NÍ Mn Ì 3d O¹ÆÌÇÝ±±ÅCLi2MnO3 Ì_eÊÍñ460 mAh/g Å é½ßCLixMnO3 Ì x2.0Í 0 mAh/g, x1.5Í120 mAh/g, x
1.0Í240 mAh/g É¨¨æ»Î·éBs[N`óÌÏ»ÍmF³êéªCXyNg`óÌÏ»ª¿Ï»Éº¤zû[ÌVtgÅtgÅé©CÇ\¢ÌÏ»Éº¤s[NVé©Ì»fªïµ¢B±Ì½ßCPÈQÆ¿ÆÌärÅÍC[dÉ Mn Ì¿Ï»ª¶¶C»Ìdqª[úd½Éñ^µÄ¢éÌ©Ç¤©Ì»fÍïµ¢B»±ÅCæê´vZÉæèV~[VðÀ{µCÚ×Ì¢ðsÁ½iFig. 4jBV~

[VÌÊÍCs[NÌ`óâÏ»ÌóÔðæ­Ä»µÄ¨èCp¢½\¢ªÃÅ

é±ÆªmFÅ«éBÉæê´v

ZÅ¾çê½d×§xªzð

ÊÏªiWIEN2k Ì aimR[h10) j·é±ÆÅ[údÌ Mn Ìdqi¿jÏ»ð©ÏàÁ½iTable 2jBLi Ì£EÉà©©íç¸Mn üèÌdqÍÏ»µÄ¨ç¸ChbNX½Éñ^µÄ¢È¢Æl¦çêéB
XÉCdr½ÉÖ^·é Mn 3d dqÌñ^ð¼ÚIFig. 4(Color online) Calculated Mn K­edge XANES spectra.

Table 2

Number of electrons estimated by spherical integration ofelectron density.

ÉÏª·é L­edge XANES XyNgÌªèðÀ{µ½BFig. 5 É¦·æ¤É[údÉº¢XyNg`óÉ°ÈÏ»Í©çêÈ¢B±ÌÊà Mn Ì¿ªÏ»µÄ¢È¢Æ¢¤ K­edge XANES ÌÊÆµµÈ¢B¿ªÏ»µÄ¢é©Ç¤©Ú×É¢·é½ßC`®IÉ MnÌ¿ðÏ»³¹CL­edge Ì XANES XyNgÌV~[VðÀ{µ½iFig. 6jB5 ¿ÌóÔð¼èµÄFig. 3(Color online) Experimental Mn K­edge XANES spectra.

Fig. 5Mn

OLi2MnO3

23.09

9.19

Li1.5MnO3

23.07

9.08

Li1.0MnO3

23.05

8.93

(Color online) Experimental Mn L2,3­edge XANES spectra.

úËõ March 2015 Vol.28 No.2 45

Fig. 6(Color online) Calculated Mn L2,3­edge XANES spectra.
Fig. 8(Color online) Calculated O K­edge XANES spectra.

ÌÙû«ªCLi ÊÉæÁÄå«­ÙÈé±ÆÉNöµÄ¢éÆl¦çêéB±êçÌÊ©çCLi ÌE£Éæèd×§xªzÉÙû«ª¶¶CXANES XyNg`óÉÏ»ðà½çµÄ¢é±Æð¦µÄ¢éB±Ìæ¤ÉC©Èç¸µàzû³fÌ¿Ï»ªÈ¢êÅàCXANES `óªå«­Ï»·éêªéÌÅC

XANES XyNgÆ¿ÌðßÉÍÓªKvÈêàéB

4. ÜÆß`ECIñdrÌ[dßöiLi E£½jFig. 7(Color online) Experimental O K­edge XANES spectra.

Ì  h b N X ½  ð Í Ì ½ ß C K­edge ¨ æ Ñ L­edge
XANES ªèCÈçÑÉæê´vZÉæé XANES XyNgV~»µ½s[NÆl¦çêCVtgÍ©çêÈ¢ªCB Ì[VðsÁ½áðÐîµ½BLi2MnO3 ÅÍCMn K­edge Ì XANES XyNg`óÏ»s[NªÌñÇÝO¹Ìs[NVtgª©çêC_fªFßçêCMn dqÌ[údÖÌñ^ªl¦çê½ªCÌ¿Ï»ª¦´³êéBÀÛV~ÀÛÍCMn Ì¿Ï»ÍÙÆñÇÈ­CO ª½Éñ^

[VÌÊ

iFig. 8jÅà¯lÉCLi Ì£EÉæè B ÌªÌs[NµÄ¢é±Æªª©Á½B±Ìæ¤ÈIÈðÍÍC¡Vtgª©çêéBTable 2 É¦·dq§xªzÌGÈ\¢ðàÂeÊÞ¿ÌðÍÉLøÅÊÏªÊ©çC[údÉº¢_fª¿Ï»µCdr½ÌéÆl¦çêéBåvöÆÈÁÄ¢é±Æª¦´³êéB± Ì æ ¤ É C K­edge XANES, L­edge XANES ª è Ææê´vZÉæéV~[VðgÝí¹é±ÆÅC¡GÈ®ð¦·êÅàC¼ÚIÉ½íðÁèµCdqÚ®Êð©Ïàé±ÆªÅ«éBÅãÉCMn Ì K­edge Ì XANES XyNgÌ`óÏ»ÉÂ¢ÄGê½¢B±Ì`óÏ»Ídqi¿jÏ»ÉR·éàÌÅÍÈ¢B±ÌXyNg`óÏ»Ì´öðl@·é½ßCXANES XyNgÌûÊË¶XyNg
ðvZµ½iFig. 9jB±êÍCFig. 10É¦·dq§xªz

46  úËõ March 2015 Vol.28 No.2Ó«{¤ðÀ{·éÉ½èCæê´vZÉÂ¢Ä²w±¸¢½åwaûPNæ¶C¨æÑCDFT­CI R[hðgp³¹Ä¢½¾¢½åã{§åwrìêæ¶É[­´Ó·éB{¤Ì XANES ªèÍ SPring­8 Ì BL16B2 É¨¢ÄÛèÔ2012B5392ÉÄÀ{µ½ÊÅéBgsbNX ¡ X üzûªõ¨æÑæê´vZÉæé`ECIñdrÌ[d@\ðÍFig. 10

Electron density distribution.

Ql¶£
1)
2)
3)
4)

5)
6)
7)
8)
9)

10)

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(Color online) Mn K­edge XANES spectrum simulations ofeach orientation.

úËõ March 2015 Vol.28 No.2 47

ÒÐîvÛº [®ïÐúYA[NÉfoCX@\ðÍE­mail: kubobuchinissan­arc.co.jp
êåFªÍ»wmªðn
1999NCHÆåwHw¤ÈCm
ÛöC¹B2008Næè»EB¡äpl®ïÐúYA[NÉfoCX@\ðÍÉ·E­mail: imainissan­arc.co.jpêåFÞ¿Èwmªðn
1997NCsåwåw@Hw¤Èm
ÛöC¹CmiHwj1997_2011NCú åC¤õB2011NC®ïÐ{dCòúYA[NåÇC2013Næè»EB2011 æ[Þ¿¤åÇ¤NæèúY©®Ôòõi±jB±ÌÔC2002_2003NCÄCmCB§åwqõ¤õB

Charge mechanism analysis of lithium ion
secondary battery: X­ray absorption
spectroscopy and rst­principles calculationsKei KUBOBUCHI
Hideto IMAI
Abstract

NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237_0061, JapanNISSAN ARC Ltd., 1 Natsushima, Yokosuka 237_0061, JapanRedox reaction behaviors of a lithium ion secondary battery were investigated by K­edge in­situ
XANES and L­edge XANES measurements combined with ab initio XANES simulation. During thecharge process, the shape of K­edge XANES spectra was found to change, suggesting contribu­
tion of Mn 3d electron to charge and discharge. The detailed analysis based on rst­principles
electronic structure calculation and ab initio XANES simulation, however, indicated that valencechange of Mn is little and rather O largely contribute to the reaction.

48  úËõ March 2015 Vol.28 No.2