A solid polymer electrolyte for aluminum ion conduction

We report on the synthesis and characterization of a solid polymer electrolyte for aluminum ion conduction. The solid polymer electrolyte is produced via the copolymerization of a low molecular weight polytetrahydrofuran and a cycloaliphatic epoxy. The crosslinked copolymer is swollen in THF solutions of different concentrations of aluminum nitrate as the aluminum ion source. The conductivity as a function of concentration is measured via AC impedance spectroscopy over a temperature range of 20-110 degrees C. We attain conductivities that increase with salt loading, reaching a value of 2.86x10(-5) S.cm(-1). Thermogravimetric analysis shows the electrolytes are stable up to 150 degrees C. Raman spectroscopy reveals complete dissociation of the aluminum nitrate salt in the electrolyte over the concentration range explored. This study establishes a polymer system and synthetic route towards solid polymer electrolytes for aluminum ion conduction, for the development of all solid-state aluminum ion batteries.