Characterization of poly(vinylidenefluoride-co-hexafluoroprolylene) membranes containing nanoscopic AlO(OH)n filler with Li/LiFePO4 cell

This paper describes the nanoscopic AlO(OH)(n) filled in porous poly(vinylidenefluoride-co-hexafluoroprolylene) membranes by phase inversion technique. The membranes were gelled with 0.5M LiPF6 in ethylene carbonate and diethyl carbonate mixture for characterization studies. The inclusion of AlO(OH)(n) nanoparticles substantially enhances the ionic conductivity and mechanical and thermal stabilities, which were observed through ac impedance, tensile strength, and differential scanning calorimetry. For example, the ionic conductivity has been increased from 2.1 x 10(-3) to 3.9 x 10(-3) S cm(-1) after the inclusion of nanoparticles. Similarly, the elongation break value is improved from 277% to 464% for the incorporation of nanoparticles. A morphological feature of the membrane was analyzed by scanning electron microscopy. Further, physicochemical properties, such as liquid uptake, porosity measurements, activation energy, and percentage of crystallinity, have also been presented. Finally, Li/polymer membrane/LiFePO4 cell was fabricated, and cycling performance of the cell was evaluated at C/10 rate. The cell delivers the initial discharge capacity 149 mAh/g at ambient temperature conditions. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3453650]