Morphological characterization of γ-LiAlO2-filled composite polymer electrolytes containing LiPF6

Morphological properties of composite polymer electrolytes based on blends of polyethylene oxide (PEO) and a perfluorinated polyphosphazene (PPz) containing LiPF₆ as lithium salt and a finely divided ceramic filler, γ-LiAlO₂, were studied by using polarizing optical microscopy and differential scanning calorimetry (DSC). A parallel study was performed on propylene carbonate plasticized composite polymer electrolytes. Results indicate that both the morphology and the thermal properties depend upon the composition of the polymer host, a result not observed in composite polymer electrolytes having the same polymer composition containing LiCF₃SO₃ as lithium salt. The incorporation of the ceramic filler at the lower concentration tested (10% by wt) has practically no effect on the thermal behavior of the samples; whereas, differences were clearly distinguished at a concentration of ceramic material of 20 wt %. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1023–1030, 1999