Supercapacitor based on electropolymerized polythiophene and multi-walled carbon nanotubes composites

Polythiophene (PTh) was electropolymerized onto multi-walled carbon nanotubes (MWCNT) modified glassy carbon (GC) electrode in ionic liquid bmimPF6 solution successfully. The different electrochemical behavior of thiophene in bmimPF6 solution was studied by cyclic voltammetry. The different morphologies of PTh films on MWCNT/GC and GC electrodes were characterized by scanning electron microscopy. Cyclic voltammetry test displays that PTh/MWCNT composites have better capacitive property than pure MWCNT and pure PTh. The galvanostatic charge–discharge and electrochemical impedance microscopy tests show that the PTh/MWCNT composites possess good capacitive characteristics. The specific capacitance of the supercapacitor is 110 F g−1. The long-term stability of the supercapacitor was also tested, and the result indicates that the specific capacitance still keeps 90% of the initial capacitance after 1000 consecutive charge–discharge cycles.