Polymer Electrolyte Based Solid State Redox Supercapacitors with Poly (3-Methyl Thiophene) and Polypyrrole Conducting Polymer Electrodes

Types I and II solid state redox supercapacitors have been constructed using polypyrrole (pPy) and poly (3-methyl thiophene) (pMeT) conducting polymer electrodes with lithium ion conducting polymer electrolyte poly(ethylene oxide) (PEO)-LiCF(3)SO(3) plasticised with poly (ethylene glycol) (PEG). The performance of the capacitors has been characterised by a. c. impedance, linear sweep voltammetry, galvanostatic charge-discharge methods and long term cycling tests. The asymmetric type II capacitors with p-doped pPy and pMeT electrodes give a capacitance value similar to 2 mF cm(-2) (equivalent to 18 F g(-1) of the total mass of the electrodes) and can be charged up to the voltage of 1.7 V. The symmetric type 1 capacitors of the configuration pPy I polymer electrolyte I pPy and pMeT I polymer electrolyte I pMeT show comparable values of capacitance but they are limited to the working voltage of < 1.0 V.