Effects of Nafion Content in Electrodes on Electric Double Layer Capacitor (EDLC) Performance

A new type of EDLC entirely composed of solid materials is discussed in this paper. It is formed essentially of electrodes based on activated carbon/Nafion and solid electrolyte membrane of Nafion 115. A series of experiments was carried out on capacitors, which utilized electrodes of different composition, to investigate the effects of Nafion content on electrochemical performances. In the present work, the electrodes were prepared by a spray technique. Homogeneous and uniform carbon/nafion layer and mechanically stable electrodes have been obtained by this technique. The performances of capacitors, which utilized these electrodes, were evaluated by cyclic voltammetry (CV) and DC charge-discharge measurements. The capacitor with electrodes at 10% of Nafion loading has given the best results. In particular, values of specific capacity of 24,7 F/g of carbon, specific energy of 3.4 Wh/Kg and maximum power of 80 kW/Kg have been obtained. Moreover, a cycling test conducted on a carbon/nafion EDLC for more than 20,000 cycles in CV mode has shown a very high stability.