SHORT COMMUNICATION Acrylamide based proton conducting polymer gel electrolyte for electric double layer capacitors B. Ganesh & D. Kalpana & N. G. Renganathan Received: 15 May 2007 / Revised: 14 April 2008 / Accepted: 1 May 2008 / Published online: 1 June 2008 # Springer-Verlag 2008 Abstract A new class of polymer gel electrolyte (PGE) was synthesized using acrylamide as host polymer and LiClO 4 as dopant. The polymer gel was subjected to electrochemical AC impedance analysis and thermal analysis. The polymer has conductivity in the order of 10 -3 S cm -1 at ambient temperature. Thermogravimetric analysis (TGA) revealed the effect of dopant on host polymer matrix. A supercapacitor was fabricated using acrylamide based polymer gel electro- lyte with activated carbon as electrode material and it was subjected to various electrochemical techniques like cyclic voltammetry, electrochemical AC impedance analysis and galvanostatic charge–discharge tests at various current densities. From cyclic voltammetry a specific capacitance of 28 F/g was obtained at a scan rate of 10 mV/s. The capacitor had good self-discharge behavior and good cycle life of more than 10,000 cycles. The coulombic efficiency was more than 95%. These results indicate that this acrylamide-based polymer gel electrolyte doped with LiClO 4 is a potential electrolyte for electric double-layer capacitors (EDLCs). Keywords Polymer gel electrolyte . Polyacrylamide . LiClO 4 dopant . Supercapacitor . Specific capacitance Introduction The increasing attention being given to electric double layer capacitors (EDLCs) or supercapacitors is stimulated by the prospect of using such devices as secondary power devices in electric vehicle propulsion, uninterrupted power supply, and also for the memory backup system [1]. A super- capacitor is different from a conventional capacitor wherein the conventional capacitors have discharge time in micro- seconds while supercapacitors require seconds. They have high power density compared to that of the usual rechargeable batteries and they exhibit both high rate charge–discharge profile and long cycle life. Hence, the performances of supercapacitors are in the midst of conventional capacitors and batteries. The concept of supercapacitors is based on the accumulation of charges in electrical double layers [2]. Power density can be further increased by the use of solid electrolytes [3]. Polymer electrolytes may be defined as membranes that possess transport properties comparable to that of liquid ionic solutions. Recently much work has been carried out in the use of solid polymer gel as electrolyte for supercapacitors [4–6]. This results in the achievement of higher capacitance, good electrochemical stability, and better compatibility between the electrodes. The application of the polymer electrolytes is restricted due to low conductivity because of the presence of some impurity, poor contact, low mechanical strength and aqueous based gels, which limit the electrostatic potential window to 1 V only. In general, capacitors with polymer gel as electrolyte have shorter life time than those with aqueous electrolyte, as the ionic conductivity decreases with the number of cycles. Few works have been done so far using polyacrylamide based gel electrolytes for solar cells and other applications [7–8]. In the present work, we synthesized a new type of polymer gel from acrylamide along with plasticers like acrylamide-2-methyl propane sulfonic acid (AMPS) and lithium perchlorate as dopant. LiClO 4 was used because of its good dissociation property and thereby increasing the Ionics (2008) 14:339–343 DOI 10.1007/s11581-008-0230-3 B. Ganesh : D. Kalpana (*) : N. G. Renganathan Central Electrochemical Research Institute, Karaikudi, Tamilnadu 630 006, India e-mail: dkalps@rediffmail.com