XPS STUDIES ON (PEO)(N)LICF3SO3 AND (PEO)(N)CU(CF3SO3)(2) POLYMER ELECTROLYTES

PEO(n)LiCF(3)SO(3) and PEO(n)Cu(CF3SO3)(2) with varying composition of n = 8-128 have been studied using X-ray Photoelectron Spectroscopy (X PS). The binding energies for various core levels of the elements pres ent in these polymer electrolytes and their observed chemical shifts a re obtained for different salt concentrations. It is shown that the in teraction between PEO and each salt is based on a complexation between the ether oxygen of PEO and the cation of the salt as well as an effe ctive cross-linking between the polymer chains of PEO through the anio n of the salt. While in PEO there is only one type of carbon atom, the above interactions in salt added PEO system have lead to the formatio n of different inequivalent carbon configurations. The observed variat ions of intensities of various peaks with increased salt concentration are interpreted in terms of varying coordination of the elements pres ent in these polymer electrolytes and their varying strength of intera ction. The usefulness and limitations of XPS to unravel the complicate d structural aspects in these materials has been demonstrated.