Characterization of composite electrolytes based on a hyper-branched polymer

Composite polymer electrolytes composed of a hyperbranched poly[bis(triethy lene glycol)benzoate] with terminal acetyl groups, LiN(CF3SO2)(2) as a lith ium salt, and an inert ceramic filler such as alpha-LiAlO2 or gamma-LiAlO2 were prepared by solvent casting method. Addition of an appropriate amount of the fillers to fully amorphous pristine polymer electrolytes led to an i ncrease in ionic conductivities and lithium ion transference numbers. All c omposite polymer electrolytes exhibited good compatibility with a Lithium m etal electrode, and also, addition of fillers improved their mechanical per formance. The alpha-LiAlO2 filler was effective far improving the electroch emical compatibility with a Lithium metal electrode, and the gamma-LiAlO2 f iller was effective for enhancing the mechanical properties of the pristine polymer electrolytes. (C) 2000 Elsevier Science S.A. All rights reserved.