화학공학소재연구정보센터
Journal of Chemical Physics, Vol.111, No.8, 3761-3768, 1999
Host-guest interactions in fluorinated polymer electrolytes: A Li-7-C-13 NMR study
Gel-type electrolytes based on fluorinated polymers are of interest for electrochemical devices. We present a Li-7-C-13 solid-state NMR and modulated differential scanning calorimetry (MDSC) study of gel electrolytes based on a copolymer poly(vinylidene fluoride) (PVdF)-hexafluoropropylene (HFP) activated with a nonaqueous solution ethylene carbonate (EC)-propylene carbonate (PC)-LiN(CF3SO2)(2). We show that the narrowing of the Li lineshape is decoupled from the glass transition. The behavior of the longitudinal relaxation times, T-1, confirms that the host polymer matrix simply behaves like a quasiinert cage for the solution. These results are confirmed by C-13 NMR at the magic angle (MAS) data, which show that the presence of the polymer does not significantly affect the chemical shift changes induced in the EC/PC carbons by the imide salt.