Polypyrrole nanoparticles were prepared by unstirred oxidation polymerization with TSA as dopant

the structure and morphologies of PPy/TSA nanoparticles were examined by X-Ray Powder Diffraction (XRD)

energy dispersive X-ray spectroscopy (EDS)

scanning electron microscopy (SEM) and transmission electron microscopy (TEM).Results showed that the diameter of the sphere-like PPy/TSA nanoparticles was ca. 40 nm.The electrochemical performances of PPy/TSA were examined by the cyclic voltammetry (CV)

galvanostatic charge-discharge tests

the results indicated that PPy/TSA nanoparticles were characterized by promising reversible capacitance and had high rate-capability.Their specific capacitance was 270 F g-1 at charging current of 10 mA cm-2.However

the specific capacitance decreased by ca. 25.5% after 1000 charging/discharging cycles.Electrochemical impedance spectroscopy (EIS) showed that the repeated charge/discharge process could increase the charge transfer resistance

and reduce the high-frequency capacity of PPy/TSA nanoparticles due to the decrease of pore diameter and specific area of the nanoparticles.In contrast

the capacity at low-frequency increased after 1000 cycles.Raman and infrared spectra proved that the deterioration of specific capacity of PPy/TSA nanoparticles was ascribed to the chemical degradation of the PPy/TSA owing to the repeated redox processes of PPy/TSA molecules.