Journal of the Korean Electrochemical Society (전기화학회지)

The Korean Electrochemical Society (한국전기화학회)
권호 표지
DOI QR코드

DOI QR Code

Synthesis and Electrochemical Properties of Li1-xFeO2-yFy-LixMnO2 (Mn/(Mn + Fe) = 0.8, 0≤y≤0.15)) Cathode Materials by Anion Substitution

음이온 치환을 이용한 Li1-xFeO2-yFy-LixMnO2 (Mn/(Mn + Fe) = 0.8, 0≤y≤0.15) 양극 활물질의 합성 및 전기화학적 특성

  • Heo, J.B. (Faculty of Applied Chemical Engineering, Center for Functional Nano Fine Chemicals, Chonnam National University) ;
  • Park, G.J. (Faculty of Applied Chemical Engineering, Center for Functional Nano Fine Chemicals, Chonnam National University) ;
  • Lee, Y.S. (Faculty of Applied Chemical Engineering, Center for Functional Nano Fine Chemicals, Chonnam National University)
  • 허정배 (전남대학교 응용화학공학부, 기능성 나노 신화학소재 사업단) ;
  • 박금재 (전남대학교 응용화학공학부, 기능성 나노 신화학소재 사업단) ;
  • 이윤성 (전남대학교 응용화학공학부, 기능성 나노 신화학소재 사업단)
  • Published : 2007.11.28
Download PDF
⟨ Previous Next ⟩

Abstract

In order to investigate the effect of fluorine ion in the $Li_{1-x}FeO_2Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8) cathode material, it was synthesized $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.05{\le}y{\le}0.15$) cathode materials at $350^{\circ}C$ for 10hrs using solid-state method. $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.0{\le}y{\le}0.1$ was composed many large needle-like particles of about $1-1.5\;{\mu}m$ and small particles of about 50-100 nm, which were distributed among the larger particles. However, $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ material showed slightly different particle morphology. The particles of $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ were suddenly increased and started to be a spherical type of particle shape. $Li/Li_{1-x}FeO_{1.9}F_{0.1}-Li_xMnO_2$ cell showed a high initial discharge capacity of 163 mAh/g and a high cycle retention rate of 95% after 50 cycles. The initial discharge capacity of $Li/Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ ($0.05{\le}y{\le}0.15$) cells increased according to the increase of F content. However, the cycleability of this cell was very rapidly decreased when the substituted fluorine content is over 0.1. We suggested that too large amount of F ion fail to substitute into the $Li_{1-x}FeO_2-Li_xMnO_2$ structure, which resulted in the severe decline of battery performance.

산소자리에 치환된 불소가 $Li_{1-x}FeO_2Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8) 양극 활물질에 미치는 영향을 고찰하기 위해 다양한 양의 불소를 치환시킨 $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.05{\le}y{\le}0.15$) 양극 활물질을 고상법을 이용하여 합성하였다. 불소 미치환 시료 및 치환양이 0.05와 0.1의 시료의 경우, $1-1.5\;{\mu}m$ 크기의 막대 형상 분말 형태에 50-100 nm정도의 작은 구형 입자들이 주위에 분포되어 있는 형태이었다. 반면, 불소 치환양이 0.15인 시료의 경우, 그 모양이 구형으로 변화되어지며 입자가 급격하게 성장하였다. 합성된 시료를 이용하여 제작된 셀들의 충 방전 수행 결과, $Li/Li_{1-x}FeO_{1.9}F_{0.1}-Li_xMnO_2$ 셀이 163 mAh/g의 가장 높은 초기용량을 보였으며 50 싸이클 후에도 95%의 높은 가역 특성을 보였다. 특히, 활물질내의 불소 치환양이 증가할수록 초기 방전용량도 같이 증가하였으나, 불소이온의 치환양이 일정량을 (y>0.1) 넘는 경우에는 산소 자리에 불소이온이 완전하게 치환되지 못하고 불순물로 존재함으로써 전지의 가역특성을 현저하게 저하시키는 요인으로 작용함을 확인하였다.

Keywords

References

  1. K. Mizushima, P. C. Jones, P. J. Wiseman, and J. B. Goodenough, '$Li_xCoO_2$ (0 https://doi.org/10.1016/0025-5408(80)90012-4
  2. J. N. Reimers, and J.R. Dahn, 'Electrochemical and In Situ X-Ray Diffraction Studies of Lithium Intercalation in $Li_xCoO_2$', J. Electrochem. Soc, 139, 2091, 62 (1992) https://doi.org/10.1149/1.2069499
  3. Tsutomu Ohzuku, Atsushi Ueda, Masatoshi Nagayama, Yasunobu Iwakoshi, and Hideki Komori, 'Comparative study of $LiCoO_2$, $LiNi_{1/2}Co_{1/2}O_2$ and $LiNiO_2$ for 4 volt secondary lithium cells', Electrochimica Acta, 38, 1159 (1993) https://doi.org/10.1016/0013-4686(93)80046-3
  4. G G Amatucci, J.M. Tarascon, and L.C. Klein 'Cobalt dissolution in $LiCoO_2-based$ non-aqueous rechargeable batteries', Solid state Ionics, 83, 167 (1996) https://doi.org/10.1016/0167-2738(95)00231-6
  5. J. C. Anderson and M. Schieber, 'Order-disorder transitions in heat-treated rock-salt Lithium Ferrite' J. Phys. Chem. Solids, 25, 961 (1962) https://doi.org/10.1016/0022-3697(64)90033-2
  6. Y. Sakurai, H. Arai, and J. Yamaki, 'Preparation of electrochemically active ${\alpha}-LiFeO_2$ at low temperature', Solid State Ionics, 113-115, 29 (1998)
  7. C. Barriga, V. Barron, R. Gancedo, M. Gracia, J. Morales, J.L. Tirado and J. Torrent, 'Lithium ferrite formation by precipitation from Fe(ni) solutions', Solid State Chem, 77, 132 (1988) https://doi.org/10.1016/0022-4596(88)90100-4
  8. J. C. Anderson, S. K. Dey, and V. Halpen, 'The magnetic susceptibilities of $LiFeO_2$', J. Phys. Chem. solids, 26, 1555 (1965) https://doi.org/10.1016/0022-3697(65)90056-9
  9. R. Kanno, T. Shirane, Y Kawamoto, Y. Takeda, M. Takano, M. Ohashi, and Y Yamaguchi, 'Synthesis, Structure, and Electrochemical Properties of a New Lithium Iron Oxide, $LiFeO_2$, with a Corrugated Layer Structure', J. Electrochem. Soc, 143, 2435 (1996)
  10. Y. Sakurai, H. Arai, S. Okada, and J. Yamaki, 'Low temperature synthesis and electrochemical characteristics of $LiFeO_2$cathodes', J. Power Sources, 68, 711 (1997) https://doi.org/10.1016/S0378-7753(96)02579-7
  11. Y. S. Lee, C. S. Yoon, Y K. Sun, K. Kobayakawa, and Y. Sato, 'Synthesis of nano-crystalline $LiFeO_2$ material with advanced battery performance', Electrochem. commun., 4, 727 (2002) https://doi.org/10.1016/S1388-2481(02)00436-8
  12. T. Matsumura, R. Kanno, Y. Inaba, Y. Kawamoto, and M. Takano, 'Synthesis, Structure, and Electrochemical Properties of a New Cathode Material, $LiFeO_2$, with a Tunnel Structure', J. Electrochem. Soc., 149, 1509 (2002) https://doi.org/10.1149/1.1516769
  13. Y. S. Lee, S. Sato, Y. K. Sun, K. Kobayakawa, and Y. Sato, 'Preparation of Mn-substituted $LiFeO_2$ : A solid solution of $LiFeO_2$ and $Li_xMnO_2$', Electrochem. Commun., 5, 359 (2003) https://doi.org/10.1016/S1388-2481(03)00067-5
  14. G. J. Park, Y S. Lee, K. S. Nahm, and Y. Sato, 'Synthesis and Electrochemical Properties of $Li_{1-x}Fe_{0.8}Ni_{0.2}O_2-Li_xMnO_2$ (Mn/ (Fe + Ni + Mn) = 0.8) Material', J. Power Sources in Press
  15. Y.-J. Kang, J.-H. Kim and Y.-K. Sun, 'Structural and electrochemical study of Li-Al-Mn-O-F spinel material for lithium secondary batteries', J. Power Sources, 146, 237 (2005) https://doi.org/10.1016/j.jpowsour.2005.03.037
  16. Yun-Sung Lee, Sung-Jun Cho, and Masaki Yoshio, 'Preparation and Electrochemical Properties of $Li_{1.1}Mn_2O_{3.9}F_{0.1}$ Material for Lithium Secondary Battery', Korean Journal of Chemical Engineering, 23(4), 566 (2006) https://doi.org/10.1007/BF02706795
  17. G. G. Amatucci, N. Pereira, T. Zheng, and J.M. Tarascon, 'Failure Mechanism and Improvement of the Elevated Temperature Cycling of $LiMn_2O_4$ Compounds Through the Use of the $LiAl_xMn_{2-x}O_{4-z}F_z$ Solid Solution', J. Electrochem. Soc., 148, A171 (2001) https://doi.org/10.1149/1.1342168