Electrical and electrochemical properties of the expanded graphite lled polythiophene nanocomposites

Abstract. In this study, graphite nanosheets were prepared by powdering expanded graphite with sonication in aqueous alcoholic solution. A facile process for the synthesis of expanded graphite lled polythiophene (PTh/EG) conducting composites was developed. The nanocomposites were fabricated via chemical polymerization of thiophene monomer in presence of expanded graphite nanosheets in various proportions. Nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Scanning Tunneling Microscopy (STM), X-Ray Diraction (XRD), Cyclic Voltammetry (CV), and electrical conductivity measurements. SEM observations on cross-sections of EG were performed to understand the microstructure occurrence during interpenetration. Electrical conductivity of PTh/EG was notably enhanced by introduction of EG. The composite exhibited good electrical conductivity of 125 Scm􀀀1 when the EG content was 0.5 wt %. CV is the most commonly used technique for evaluation of electrochemical properties of a lm on the electrode surface. The composites also showed excellent electrochemical reversibility at the scan rate of 50 mVs􀀀1 and maximum reversible electrochemical response was almost unchanged even up to 100 cycles. The stability of oxidation and reduction peaks of nanocomposites in cyclic voltammetry in up to 100 cycles shows that the obtained nanocomposites are very appropriate to be used in rechargeable batteries.