Study on ionic conductivity, dielectric and electrochemical properties of solid polymer electrolyte for battery applications

A novel solid polymer electrolyte (SPE) comprising of corn starch (CS) and sodium iodate (NaIO3) as ion-conducting species were prepared by using the solution casting technique. Electrochemical impedance spectroscopy (EIS) was performed to obtain information about the conductivity and dielectric studies of the polymer-salt complex. It was found that the sample with 3 wt% of NaIO3 has achieved the maximum conductivity with a value of 1.08 x 10(-4) Scm(-1) at ambient temperature. Dielectric and modulus studies were carried out to better understand the conductivity behaviour of the SPE samples. From results, it shows that non-Debye type of CS-NaIO3 SPE. It is observed that the dielectric constant (epsilon(r)) increases sharply towards the lower frequencies due to electrode polarization effect. On the other hand, the peaks observed for imaginary of the modulus (M-i) are due to conductivity relaxation which shows the material is ionic conductors. An electrochemical cell fabricated using the highest ionic conduction of SPE films produced an open voltage of 1.51 V and an increased discharge time is seen with the decrease of current given. The results highlight the prepared SPE film has the ability to improve the performance of a primary sodium-ion battery in a safe mode.