Nanostructured block copolymer dry electrolyte

We report on the synthesis and characterization of a solid-state polymer electrolyte with enhanced lithium transport based on a self-assembled diblock copolymer. The diblock copolymer consists of a poly(ethylene oxide) (PEO) block and a random copolymer of methyl methacylate (MMA) and lithium salt of methacrylic acid (MAALi). Lithium bis(oxalato)borate, LiBC4O8 (LiBOB) was used as salt in the dry electrolyte. Impedance and temperature studies were carried out to characterize the conductivity performance of the electrolyte. The diblock copolymer [PEO-b-(PMMA-ran-PMAALi)] with added LiBOB (in the molar ratio ethylene oxide:LiBOB=3:1) was used to form flexible translucent films, which exhibited an average ionic conductivity value of 1.26x10(-5) S cm(-1) at room temperature (21 degrees C). Transmission electron microscopy was performed to characterize the morphology of the polymer, and differential scanning calorimetry was carried out to study the thermal properties of the electrolyte. (C) 2008 The Electrochemical Society.