Journal of Applied Electrochemistry, Vol.41, No.2, 197-206, 2011
Performance of EDLCs using Nafion and Nafion composites as electrolyte
We present the electrochemical performance of solid-state EDLCs constructed using composites of perfluorosulfonic acid polymer (Nafion) with micro porous polytetrafluoroethylene (PTFE) membrane and with cellulose acetate (CA), as electrolyte with carbon as electrodes (surface area: 260 m(2) g(-1)). The performance is compared with EDLCs constructed with perfluorosulfonic acid polymer as electrolyte. Scanning electron microscopy is used to study the morphology of the composite electrolyte while micro-Raman and IR measurements determine the integrity of the composite. The performance of the EDLC with perfluorosulfonic acid and PTFE composite electrolyte is good and comparable with the performance of the EDLC with pure perfluorosulfonic acid polymer electrolyte. A specific capacitance of 16 F g(-1) is obtained for this EDLC with a maximum working potential of 2.0 V. There is an increase in the equivalent series resistance value from 0.08 Omega for the Nafion EDLC to 4.1 Omega for the Nafion/PTFE composite EDLC. However, the performance of the EDLC with the composite of Nafion/CA is poor due to substantial increase in ESR. The probable reasons are discussed.
Keywords:Electric double layer capacitor;Electrochemical impedance spectroscopy;Perfluorosulfonic acid;Nafion composites;Micro-Raman;Charge-discharge