Flexible magnesium-ion conducting polymer electrolyte membranes: mechanical, structural, thermal, and electrochemical impedance spectroscopic properties

This paper reports investigations on flexible magnesium-ion-conducting polymer electrolyte membranes using mechanical, structural, and electrochemical impedance spectroscopic analysis. XRD studies reveal significant changes in structural character on varying the concentration of propylene carbonate-diethyl carbonate (PC-DEC) organic solvent within the polymer electrolyte matrix. SEM and AFM studies indicate variation in surface morphology and maximum roughness height by introducing PC-DEC in increasing amount. The plasticized polymer electrolyte membrane with optimum concentration of 15 wt% PC-DEC demonstrates magnesium-ion conductivity of 3 × 10 − 5 s cm − 1 at room temperature. This flexible electrolyte has Young’s modulus of 100 N mm − 2 , mechanical strength of 2 Kgf, and ability to withstand stress of 6 N mm − 2 and strain of 7 N mm − 2 at a maximum load of 10 Kgf. The electrolyte membranes do not show any degradation after stretching and rolling it for hundred times. The electrolyte membrane offer electrochemical stability window of ~ 3.5 V and Mg 2+ transport number of 0.32. The reported electrolyte membranes can be employed in fabricating flexible magnesium batteries.