INSITU ATTENUATED TOTAL REFLECTION FOURIER-TRANSFORM INFRARED-SPECTROSCOPY STUDIES OF THE POLYETHYLENE OXIDE LICIO4-METALLIC LITHIUM INTERFACE

The reactivity of polyethylene oxide/LiClO4 solid polymer electrolyte with metallic lithium has been investigated using attenuated total reflection Fourier transform infrared spectroscopy as an in situ probe of the vibrational properties of the interface. The results obtained have indicated that metallic lithium electrodeposited in situ reacts with PEO, leading to an irreversible cleavage of the ether functionality to generate the corresponding alkoxide as a product. This was evidenced by the appearance of a well-defined (ether-related) peak at 1110 cm-1, as well as a rather broad and not as well-defined peak of opposite polarity at 1200 cm-1. Also found in the spectra was a feature at 1090 cm-1 ascribed to perchlorate ions which migrate into and out of the near-surface region to preserve electroneutrality.