Lithium perchlorate doped plasticized chitosan and starch blend as biodegradable polymer electrolyte for supercapacitors

Abstract

Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and starch, plasticized with glycerol, as host polymer and lithium perchlorate (LiClO 4) 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 LiClO 4 concentration at temperature range of 298-343 K using electrochemical impedance spectroscopy. The maximum conductivity is found to be 3.7 × 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 LiClO 4 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. © 2012 Elsevier Ltd.