Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and starch, plasticized with glycerol, as host polymer and lithium perchlorate (LiClO4) as a dopant is prepared by solution casting technique. The variation of conductivity has been investigated as a function of polymer blend ratio, plasticizer content, and LiClO4 concentration at temperature range of 298-343 K using electrochemical impedance spectroscopy. The maximum conductivity is found to be 3.7 x 10(-4) S cm(-1) at room temperature for 60:40 (CS/starch) concentration. The dielectric properties of the electrolyte film exhibit a long tail feature indicating good capacitance. The activation energy of all samples is evaluated using the Arrhenius plot and it is found to be 0.52-0.75 eV. The DSC thermogram peaks for CS-starch blends decreases with increase in the LiClO4 content. A carbon-carbon supercapacitor is fabricated using suitable blend electrolyte ratio and its electrochemical characteristics are discussed at various temperatures and current density. This supercapacitor shows a fairly good specific capacitance of 133 Fg(-1). (C) 2012 Elsevier Ltd. All rights reserved.