Microphase structure of SEI on HOPG

The solid electrolyte interphase (SEI) on both lithium and carbonaceous electrodes consists of many different materials including some nonconductive polymers. Several previous investigators were unable to find evidence of polymers in the solid electrolyte interphase, however, these authors suggest that these materials form simultaneously and precipitate on the electrode as a mosaic of microphases. The objective of this study was to provide details of the microphase morphology of the solid electrolyte interphase formed on HOPG in in LiPF{sub 6}--EC solutions. Result confirmed the evidence of a lateral distribution of solid electrolyte interphase materials, and also provided direct evidence for the existence of polymers in the solid electrolyte interphase. Heavy organic fragments were found mostly at the surface of the basal solid electrolyte interface. Thickness of the interphase on the basal plane was found to be three to five times smaller than on the cross section. 127 refs., 9 figs.