X-RAY PHOTOELECTRON-SPECTROSCOPY STUDIES ON PEO(N)MBR(2) (M=CO, NI, ZN) SOLID ELECTROLYTES

PEO(n)MBr(2) (M=Co, Ni, Zn) electrolytes were prepared at room tempera ture with values of n ranging from 128 to 8. X-ray photoelectron spect roscopy studies for each electrolyte system indicate a characteristic interaction of the -CH2-CH2-O-chain of PEO with the divalent cations. While in PEO there is only one kind of carbon, these interactions have led to the formation of inequivalent carbons in all three electrolyte systems with increased salt concentration. Strongest cation interacti on is identified for all systems at a salt concentration corresponding to n congruent to 16. Whereas the cations are found to change their c oordination with varying salt concentration, the anions of each system are found to have nearly unchanged coordination. These results reveal the PEG(n)MBr(2) systems with M=Co, Ni and Zn as complexes formed by the ether oxygen of PEO and each cation and an effective cross-linking between the -CH2-CH2-O-chain and the anion of the salt.