Synthesis and electrical response of single-ion conducting network polymers based on sodium poly(tetraalkoxyaluminates)

Sodium ion conducting polyelectrolytes containing a network of tetraalkoxyaluminates linked by polyethers have been prepared by the reaction of NaAlH₂(OCH₂CH₂OCH₃)₂ with low molecular weight poly(ethylene glycols) (PEG(300), -(400), -(600), -(1000)). The conductivities of these electrolytes are comparable to those observed for complexes of sodium tetraalkoxyaluminate salts with poly(ethylene oxide)-based host polymers (ca. 10^-6 S cm^-1 at 60°C) indicating strong Na⁺-alkoxyaluminate ion pairing. A conductivity enhancement of 110-fold at 40°C is observed when the cation complexing agent cryptand [2.2.2] is added to the polyelectrolyte prepared from PEG(400). A similar conductivity enhancement was observed (140-fold at 40°C) when cryptand is added to salt complexes; the conductivity enhancement is likely due to a decrease in ion pairing in the electrolytes.