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LiFePO4와 Li4P2O77Li MAS NMR 특성 연구

7Li MAS NMR studies of Li4P2O7 and LiFePO4 materials

  • 투고 : 2010.11.15
  • 심사 : 2011.01.07
  • 발행 : 2011.02.28

초록

[ $^7Li$ ]Magic Angle Spinning(MAS) NMR Spectroscopy를 활용하여 $Li_4P_2O_7$$LiFePO_4$ 물질에서 $^7Li$ 핵의 NMR 특성 및 화합물 분자내의 국부적 구조 연구를 수행하였다. $Li_4P_2O_7$$LiFePO_4$ 물질 연구는 리튬이온전지에서 고체-전해질 경계상(SEI, solid-electrolyte interphase) 물질 연구를 위한 것이다. $Li_4P_2O_7$$LiFePO_4$ 분말은 고상합성법으로 제조하였다.$^7Li$MAS NMR 실험은 $27^{\circ}C$에서 $97^{\circ}C$의 영역에서 변온 실험을 수행하였으며 이는 주변 온도 변화 환경에서 $Li_4P_2O_7$ 물질 내의 Li 핵의 구조 변화를 관찰하기 위한 것이다. $^7Li$ MAS NMR 측정 결과 시료 온도가 $27^{\circ}C$에서 $97^{\circ}C$의 온도 분포 영역에서는 $Li_4P_2O_7$ 물질 내부의 Li 핵은 구조적으로 변화하지 않는 것이 확인되었다. 금번 실험을 통하여 $LiFePO_4$ 분말에 5.0 wt%이내로 포함되어있는 $Li_4P_2O_7$ 물질의 $^7Li$ MAS NMR 신호를 측정할 수 있는 측정 조건을 알았다.

[ $^7Li$ ]Magic Angle Spinning (MAS) NMR spectroscopy has been used to study the lithium local environments in $Li_4P_2O_7$ and$LiFePO_4$ materials. The purpose of this study was to know the structure of the solid electrolyte interphase (SEI) in lithium ion cells composed of $LiFePO_4$ as cathode material. $Li_4P_2O_7$ and $LiFePO_4$ were prepared by a solid-state reaction. The $^7Li$ MAS NMR experiments were carried out at variable temperatures in order to observe the local structure changes at the temperatures in $Li_4P_2O_7$ system. The $^7Li$ MAS NMR spectra of in $Li_4P_2O_7$ indicate that the lithium local environments in $Li_4P_2O_7$ were not changed in the temperature range between $27^{\circ}C$ and $97^{\circ}C$ Through this work, we confirmed that the small amount of $Li_4P_2O_7$ less than 5.0 wt% in $LiFePO_4$ could be clearly measured by the $^7Li$ MAS NMR spectroscopy at high spinning rate over than 11 kHz.

키워드

참고문헌

  1. A.K. Padhi, K.S. Nanjundaswamy and J.B. Goodenough, "Phosphor-olivines as positive-electrode materials for rechargeable lithium batteries", J. Electrochem. Soc. 144(4) (1997) 1188. https://doi.org/10.1149/1.1837571
  2. M. Stanley Whittingham, "Lithium batteries and cathode materials", Chem. Rev. 104 (2004) 4271. https://doi.org/10.1021/cr020731c
  3. A. Yamada, M. Hosoya, S. Chung, Y. Kudo, K. Hinokuma, K. Liu and Y. Nishi, "Olivine-type cathodes Achievements and problems", Journal of Power Sources 119-121 (2003) 232. https://doi.org/10.1016/S0378-7753(03)00239-8
  4. Clare P. Grey and Licolas Dupre, "NMR studies of cathode materials for lithium-ion rechargeable batteries", Chem. Rev. 104 (2004) 4493. https://doi.org/10.1021/cr020734p
  5. B. Kang and G. Ceder, "Battery materials for ultrafast charging and discharging", Nature 458 (2009) 190. https://doi.org/10.1038/nature07853
  6. K. Zaghib, J.B. Goodenough, A. Mauger and C. Julien, "Unsupported claims of ultrafast charging of $LiFePO_4$Li-ion batteries", Journal of Power Sources 194 (2009) 1021. https://doi.org/10.1016/j.jpowsour.2009.05.043
  7. D. Arcon, A. Zorko, R. Dominko and Z. Jaglicic, "A comparative study of magnetic properties of $LiFePO_4 $and $LiMnPO_4$", J. Phys: Condens. Matter 16 (2004) 5531. https://doi.org/10.1088/0953-8984/16/30/014
  8. Y.J. Lee, F. Wang and C.P. Grey, " $^6Li$and $^7Li $ MAS NMR studies of lithium manganate cathode", J. Am. Chem. Soc. 120 (1998) 12601. https://doi.org/10.1021/ja9817794
  9. M.C. Tucker, M.M. Doeff, T.J. Richardson, R. Finones, J.A. Reimer and E.J. Carins, "Hyperfine fields at the Li site in $LiFePO_4$-type olivine materials for lithium rechargeable batteries: A $^7Li $MAS NMR and SQUID study", Electrochemical and Solid-State Letters 5 (2002) A95. https://doi.org/10.1149/1.1464505
  10. B.M. Meyer, N. Leifer, S. Sakamoto, S.G. Greenbaum and C .P. Grey, "High field multinuclear NMR investigation in lithium rechargeable batteries", Electrochemical and Solid-State Letters 8(3) (2005) A145. https://doi.org/10.1149/1.1854117
  11. C.P. Grey and S.G. Greenbaum, "Nuclear magnetic resonance studies of lithium-ion battery materials", MRS Bulletin/August (2002) 613.
  12. Y. Wang, X. Guo, S. Greenbaum, J. Liu and K. Amine, "Solid electrolyte interphase formation on lithium-ion electrodes", Electrochemical and Solid-State Letters 4(6) (2006) A68.
  13. C.V. Ramana, A. Ait-Salah, S. Utsunomiya, A. Mauger, F. Gendron and C.M. Julien, "Novel lithium iron pyrophosphate ($LiFe_{1.5}P_2O_7)$ as a positive electrode for Liion batteries", Chem. Mater. 19 (2007) 5319. https://doi.org/10.1021/cm071526m
  14. C.M. Doherty, R.A. Caruso, B.M. Smarsly, P. Adelhelm and C.J. Drummond, "Hierarchically porous monolithic $LiFePO_4$/carbon composite electrode materials for high power lithium ion batteries", Chem. Mater.21 (2009) 5300. https://doi.org/10.1021/cm9024167
  15. G,R. Gardiner and M.S. Islam, "Anti-site defects and ion migration in the $LiFe_{0.5}Mn_{0.5}PO_4 $ mixed-metal cathode materials", Chem Mater. 22 (2010) 1242. https://doi.org/10.1021/cm902720z
  16. S. Hame1et, P. Gibot, M. Casas-Cabanas, D. Bonnin, C.P. Grey, J. Cabana, J. Leirche, J.R. Carvajal, M. Courty, S. Levasseur, P. Carlach, M.V Thournout, J. Tarascon and C. Masquelier, "The effects of moderate thermal treatments under air on $LiFePO_4 $-based nano powders", J. Mater. Chem. 19 (2009) 3979. https://doi.org/10.1039/b901491h
  17. L.J,M. Davis, I. Heinmaa and G.R Goward, "Study of lithium dynamics in monoclinic $Li_3Fe_2(PO_4)_3 $ using $^6LiVT$ and 2D exchange MAS NMR spectroscopy", Chem Mater. 22 (2010) 769. https://doi.org/10.1021/cm901402u