For device fabrication, materials needs to satisfy 3Es (economical, environment friendly and easy to prepare) along with technical characteristics. Present paper reports an electrolyte synthesized by modifying potato starch by solution cast technique which is easy to synthesize, stretchable, bendable and twistable low cost (similar to INR 15/cm(2)) free standing electrolyte film having wide electrochemical stability window (ESW similar to 2.4 V), low equivalent series resistance (ESR similar to 1.7 Omega) and small ion relaxation time (15 mu). Supercapacitors are fabricated using this electrolyte with two different electrodes (teflon coated carbon cloth and anodized aluminium). With laboratory prepared anodized Al as electrode, the electrochemical stability window is >4V, ESR is <2 Omega and capacitance of similar to mF is obtained. Approximately -80 degrees phase angle is obtained which remains constant from 1 Hz to 10 kHz range which covers the frequency requirement of ac line filtering application. The coulombic efficiency estimated from charging/discharging curves have values > 98% which approximately remains constant in studied number of cycle. All these indicate that prepared electrolyte is a potential candidate for electrochemical device applications. (C) 2018 Elsevier Ltd. All rights reserved.