New Separators Based on Non-Polyolefin Polymers for Secondary Lithium Batteries

  • Seol, Wan-Ho ;
  • Lee, Yong-Min ;
  • Lee, Jun-Young ;
  • Han, Young-Dal ;
  • Ryu, Myung-Hyun ;
  • Park, Jung-Ki
  • Published : 2007.05.28


New porous separators based on non-polyolefin materials including the blend of poly (vinyl chloride) (PVC)/poly (vinylidene fluoride-co-hexafluoropropylene) (P(VdF-co-HFP)/poly(methyl methacrylate) (PMMA), and the porous separator based on poly (vinylidene fluoride) (PVdF) were prepared by phase inversion method. The porosity and morphology were controlled with phase inversion rate, which is governed by the relative content of non-solvent and solvent in coagulation bath. To enhance tensile strength, the solvent pre-evaporation and uni-axial stretching processes were applied. The ionic conductivity was increased with increasing stretching ratio, and tensile strength was increased with increasing solvent pre-evaporation time and stretching ratio. The 200% stretched PVdF separator showed 56 MPa of tensile strength, and the ionic conductivity of the stretched PVdF separator was $8.6{\times}10^{-4}\;S\;cm^{-1}\;at\;25^{\circ}C$.


Separator;Membrane;Poly (vinyl chloride);Poly (vinylidene fluoride);Phase inversion;Stretching process;Lithium rechargeable battery


  1. W. H. Seol, Y. M. Lee, J. K. Park, 'Preparation and characterization of new microporous stretched membrane for lithium rechargeable battery', J. Power Sources, 163, 247-251 (2006)
  2. P. Arora and Z. Zhang, 'Battery separators', Chem. Rev., 104, 4419-4462 (2004)
  3. 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)
  4. 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)
  5. M. Mulder, Basic Principles of Membrane Technology; Kluwer Academic Publishers, Dordrecht, The Netherlands, (1991)
  6. E. Fontananova, J. C. Jansen, A. Cristiano, E. Curcio, E. Drioli, 'Effect of additives in the casting solution on the formation of PVDF membranes', Desalination, 192, 190 (2006)
  7. Y. M. Lee, J. W. Kim, N. S. Choi, J. E. 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)
  8. A. Salimi, A. A. Yousefi, 'FTIR studies of B-phase crystal formation in stretched PVdF films', Polymer Testing, 22, 699-704 (2003)
  9. C. A. Smolders, A. J. Reuvers, R. M. Boom and I. M. Wienk, 'Microstructure in phase-inversion membranes. Part I. formation of macrovoids', J. Membrane Science, 73, 259-275 (1992)
  10. J. A. Lee, W. H. Seol, Y. M. Lee, and J. K. Park, 'Enhancement of the ionic conductivity and mechanical strength of micro-porous separator by uni-axial drawing', J. Korean Electrochemical Society, Vol 9, 1, 29-33 (2006)