X-ray absorption studies of PEO-ZnBr sub 2 complexes

Polyethylene oxide (PEO)-ZnBr{sub 2} complexes, of the composition ZnBr{sub 2}(PEO){sub 8}, were investigated by extended x-ray absorption fine structure spectroscopy in the temperature range 25 to 120{degrees} C. The results at all temperatures were very similar, and were consistent with the presence of largely undissociated ZnBr{sub 2} species that were coordinated with four oxygens from the PEO. The respective calculated Zn-Br and Zn-O bond lengths were 2.34 and 2.23 {Angstrom}. There is evidence of some ZnBr{sub 2} dissociation at higher temperatures. In this paper a mechanism, based on Br{sup {minus}} ion hopping between anchored species of ZnBr{sub 2} and ZnBr{sup +} in PEO, is proposed to explain reported transport number and conductivity data.