Preparation and characterisation of PEOHg(ClO₄)₂ complexes and some thoughts on ion transport in polymer electrolytes

A new solid polymer electrolyte, PEOHg(ClO₄)₂ has been prepared and characterised over a composition range 100 =x= 4, where x represents the molar ratio of EO units to salt. Films of this material are amorphous at high salt concentrations and there is no evidence for the formation of a crystalline polymer-salt complex over the entire composition range studied. Electrical measurements indicate that both cations and anions are mobile, with a cation transference number of 0.25±0.05 at 52°C for an EO/salt molar ratio of 20:1. The overall conductivity of PEOHg(ClO₄)₂ is significantly higher than that of other strictly anhydrous polymer electrolytes containing mobile divalent cations, previously reported. The variation of conductivity with temperature and composition is discussed, and cation mobility in general is considered in terms of hard and soft character, and in relation to the lability of the coordinated etheroxygens. © 1988.