Vinylidenefluoride-hexafluoropropylene copolymers as hybrid electrolyte components for lithium batteries

Hybrid polymer electrolytes based on P(VdF-HFP) copolymers exhibit high ionic conductivity and fair mechanical performances. Two preparation methods are tested in order to optimise the properties of P(VdF-4.5 mol% HFP)-based matrices, activated by different concentrations of a 1.5 M solution of LiN(CF3SO2)(2) in an EC/PC mixture: (1) the extraction/absorption procedure; (2) the conventional solvent casting. Conductivity values exceeding 10(-4) Omega(-1) cm(-1) are found in samples containing 60 wt.% of electrolyte solution. In general, the films obtained by casting show a lower conductivity than the samples prepared by the extraction/absorption method, and such a difference decreases when the electrolyte fraction increases. (C) 1999 Elsevier Science S.A. All rights reserved.