Polymer electrolyte has seen tremendous growth after works of Fenton & Armand, and energy devices are being produced at commercial level. Today's social lifestyle needs miniaturized energy devices at every step of life; consequently, they add up to chemical garbage of the world. The sustainable development in the field needs eco-friendly energy devices. Hence, starch (being at low cost, abundant in nature and eco-friendly) has received great scientific attention. In recent past, many attempts have been made to modify the various starches to get fast ion-conducting materials. In our laboratory, also, wheat, potato, rice and arrowroot starches have been modified with different sodium salts, and in each case, considerably high-conducting (> 10(-3) S/cm) films have been found. In present case, also, a high-conducting transparent film (10(-2) S/cm) is obtained with corn starch and NaClO4 salt after being crosslinked with glutaraldehyde (GA). Bode plots (both phase and magnitude), capacitive-response plot, capacitive-frequency plots and linear sweep voltammetry curves are analysed to explain the possibility of using the prepared electrolyte in capacitive device. The larger electrochemical stability window (ESW) similar to 2.4 V and smaller ion relaxation time similar to 65 mu s make it a potential candidate for device fabrication. The equivalent series resistance is similar to 6.252 Omega for 0.8-mm-thick sample.