Capacitance characteristic of PEDOT electrodeposited on different substrates

Poly(3,4-ethylenedioxythiophene) (PEDOT) has been electrochemically deposited on carbon paper (CP), stainless steel mesh (SSM), stainless steel (SS), and indium tin oxide (ITO) by unipolar-pulsed method. The surface morphology, micro-structure, and electrochemical capacitance for PEDOT/substrates were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The electrochemical capacity measurements of the PEDOT/CP electrode in 0.5 M H 2 SO 4 shows high mass-specific capacitance of 126.24 F/g at a 1 mA/cm 2 , which is consistent with the specific capacitance of 126.75 F/g at 5 mV/s. Compared with PEDOT/SSM, PEDOT/SS, and PEDOT/ITO, PEDOT/CP electrode shows better capacitive performance, which presents good rate performance of 76.78% at 5 mA/cm 2 and charge-discharge stability with the capacitance retention rate of 80.57% for 5000 cycles. SEM result shows PEDOT maintained the spindle-like structure along with the threads of each carbon fiber, which are densely packed and randomly oriented forming the porous structure.