External microbeam PIGE study of Li and F distribution in PVdF/HFP electrolyte gel polymer for lithium battery application

Studies of Li and F distribution in a series of gel polymer electrolyte sam ples containing lithium salt solution have been performed by microbeam scan ning of the sample cross-section using PIGE spectroscopy. In order to prese rve gel polymer during experiment, all measurements have been performed wit h an external microbeam (in air), using a focused 4 MeV proton beam and a 5 0 mu m thick Kapton exit foil. The main contribution to the deterioration o f the beam spatial resolution comes from the ion multiple scattering in the vacuum-air interface foil and in atmosphere. Direct depth profiling of lit hium and fluorine is not possible since the ion energy straggling in the fo il and in atmosphere precludes the use of nuclear resonant reactions. Later al scans over the sample cross-section were performed with PIGE spectroscop y used for the determination of fluorine and lithium distributions. (C) 200 0 Elsevier Science B.V. All rights reserved.