EXAFS STUDIES ON COBALT POLYMER ELECTROLYTES

Results for the local structure of polymer electrolytes based on poly( ethylene oxide), PEG, containing CoBr2 salts at different concentratio ns are discussed. The use of different drying procedures which can res ult in a mixed morphology film containing both amorphous and crystalli ne regions (spherulites) has been investigated. The EXAFS results show that each cobalt (on average) is associated with 4 oxygens and 3 brom ines for all concentrations and drying regimes. The Co-O distance was found to be similar for most of the samples at similar to 2.110 Angstr om but this distance reduces slightly for the more dilute samples, ind icating a possible greater interaction between the polymer chains and the cations. The Co-Br distance remains constant at similar to 2.380 A ngstrom for all drying regimes and concentrations.