Effect of fillers on magnesium–poly(ethylene oxide) solid polymer electrolyte

A solid polymer electrolyte (SPE) film consisting of poly(ethylene oxide) (PEO) with magnesium chloride as electrolytic salt and B₂O₃ as the filler has been prepared by solution casting technique. The polymeric film was flexible and self-standing with proper mechanical strength and studied for application in a solid-state rechargeable magnesium battery. The interactions between the filler and PEO chains are studied by differential scanning calorimeter and Fourier transform infrared techniques. Composition of SPE is optimized, and maximum conductivity is obtained at 2 wt% B₂O₃. Filler seems to increase the number of free magnesium cations by decoordinating the bond between magnesium cations and ether oxygen of PEO. Cyclic voltammetry results show the reversible capability of magnesium electrode. Solid-state magnesium cell employing magnesium anode, SPE, and manganese oxide was assembled, and its open circuit voltage is found to be 1.9 V.