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Enhancement of the Ionic Conductivity and Mechanical Strength of Micro-porous Separator by Uni-axial Drawing

  • Lee Je-An (Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology) ;
  • Seol Wan-Ho (Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology) ;
  • Lee Yong-Min (Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology) ;
  • Park Jung-Ki (Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology)
  • Published : 2006.02.01

Abstract

A new porous separator based on poly(vinyl chloride) (PVC)/poly(vinylidene fluoride-co-hexafluoro-propylene) (P(VdF-co-HFP)/poly(methyl methacrylate) (PMMA) was prepared by a phase inversion method. To enhance mechanical property, the membrane was stretched uniaxially at high temperature. Tensile strength and ionic conductivity were measured for various draw ratios. The tensile strength and ionic conductivity were increased with increasing draw ratio. The tensile strength of the separator reached 52MPa after stretching to draw ratio of 5, and the ionic conductivity of the separator was increased from $1.9Xs10^{-4}S/cm\;to\;4.6X10^{-4}S/cm\;at\;25^{\circ}C$. The stretched separator immersed in liquid electrolyte was electrochemically stable up to 4.7 V. The cell based on the stretched separator was maintained at about 99% of the initial discharge capacity after 10th cycle operation at 0.2C rate.

References

  1. P. Arora and Z. Zhang, 'Battery separators', Chem. Rev., 104,4419-4462 (2004) https://doi.org/10.1021/cr020738u
  2. Y. M. Lee, J. W. Kim, N. S. Choi, J. A. Lee, W. H. Seol, and J. K. Park. 'Novel porous separator based on PVdF and PE nonwoven for rechargeable lithium batteries', J. Power Sources, 139, 235-241 (2005) https://doi.org/10.1016/j.jpowsour.2004.06.055
  3. H. Izumi, Asahi Kasei, Japan patent, 2001179062 (2001)
  4. N. Yusuke., Asahi Kasei, Japan patent, 2001226515 (2001)
  5. K. Koichi, Japan patent, 220833 (1990)
  6. R. Hikmet, 'New lithium-ion polymer battery concept for increased capacity', J. Power Sources, 92, 212-220 (2001) https://doi.org/10.1016/S0378-7753(00)00529-2
  7. H.- T. Kim, J. K. Park, and K. H. Lee, 'Impedance spectrosopic study on ionic transport in a pH sensitive membrane', J. Mem. Sci., 115, 207-215 (1996) https://doi.org/10.1016/0376-7388(96)00028-2
  8. S. V. Vlasov et al. Polym. Eng. Sci., 35, 2 (1995)
  9. S. Rajendran, O. Mahendran, and T. Mahalingam, 'Thermal and ionic conductivity studies of plasticized PMMA/PVdF blend polymer electrolytes', European Polymer Journal, 38, 49-55 (2002) https://doi.org/10.1016/S0014-3057(01)00140-9
  10. N. Kan, Japan patent, 61106640 (1986)
  11. D. W. Kim, Y. R. Kim, J. K. Park, and S. J. Moon, 'Electrical properties of the plasticized polymer electrolytes based on acrylonitrile-methyl methacrylate copolymers', Solid State Ionics, 106, 329-337 (1998) https://doi.org/10.1016/S0167-2738(97)00498-0
  12. M. Gilbert, Z. Liu, and D. J. Hitt, 'Biaxial orientation of poly(vinyl chloride) compounds: Interaction between drawing, structure, and properties', Polm. Eng. Sci., 37, 11 (1997)