Arrowroot + NaI: a low-cost, fast ion conducting eco-friendly polymer electrolyte system

Energy devices are the lifeline of today’s society, and hence, they are produced in large number resulting in tremendous increase of chemical garbage. Hence, the scientific community is thoroughly looking for eco-friendly alternatives for sustainable development. Polymer electrolytes have received greater attention, and their biodegradable/eco-friendly substitutes are being studied in many laboratories. Starch, being low cost, eco-friendly, and abundant in nature, has attracted many scientists. In our laboratory, crosslinked starches (arrowroot, corn, wheat, and rice) are being used for electrolyte preparation. Present paper discusses the results of arrowroot starch crosslinked with glutaraldehyde and complexed with NaI. The highest conductivity was found to be of the order of 10−2 S/cm. In these systems, conductivity goes on increasing starch/salt ratio up to 1:1 which can be correlated with salt plasticization effect. Phase angle remains above −75° for nearly 3 orders of frequency. The estimated ion relaxation time is 14 μs, and the equivalent series resistance is ∼3 Ω which indicates fast ion response. Cp/Cs ratio remains ∼1 for 4 order of frequency. Such behavior indicates that these materials are suitable for the fast charging-discharging devices.