Preparation And Characterization Of Conducting Polypyrrole Nanoparticles As Supercapacitor Electrode

The physical chemical properties of PPy/TSA particles prepared by different methodswere studied in this paper. The electrochemical properties of PPy/TSA particles aremeasured in0.5M Na2SO4electrolyte, Results showed that the PPy/TSA had high ratecapability; However, the specific capacitance decreased by ca.25.5%after1000charging/discharging cycles. Electrochemical impedance spectroscopy （EIS） indicated thatthe repeated charge/discharge process could increase the charge transfer resistance, and thehigh-frequency capacity of PPy/TSA nanoparticles due to the decrease of pore diameterand specific area of the nanoparticles, in contrast, the double layer capacity produced inthe deep pores increases. Raman and infrared spectra proved that the deterioration ofspecific capacity of PPy/TSA nanoparticles was ascribed to the chemical degradation ofthe PPy/TSA owing to the repeated redox processes of PPy/TSA molecules and therepeated swell/shrink in the conducting PPy backbones.The MnO₂/PPy/TSA nanoparticles are synthesized by KMnO4as oxidation, itselectrochemical properties are characterized by FTIR、SEM、BET、CV、EIS andgalvanostatic charge/discharge methods, and so on. Results show that the BET surfacearea is123.8m²/g with a predominant pore size of3.5nm, at3mA/cm²the specificcapacitance is376F/g in the potential range of-0.1⁰.9V, the capacitance decreased about7.3%after500charge/discharge cycles and compared to PPy/TSA, the specificcapacitance improved about10.3%.In order to investigate the effect of morphology on capacitance, we prepared anotherPPy/TSA nanomaterial by the template method. Under acid environment, MnO₂which gotby the hydrothermal method were used as oxidation and template to synthesize PPy.Results from SEM and TEM demonstrate that PPy/TSA are hollow structure nanofibers,its BET surface area is107.56m²/g and have a large pore size distribution, Besides, itexhibits a higher specific capacitance about305F/g at10mA/cm². Nevertheless, thecapacitance of PPy/TSA still decreased a lot during the charge/discharge process. At last,we prepared the AC/PPy/TSA composite by ultrasonic mixing method, different massratios of AC and PPy/TSA are studied, CV and EIS results indicate when the ratio is6:4,the composite displays excellent electrochemical properties, therefore, we choose it to investigate the composite physical chemical characterizations. It’s calculated that the BETsurface area is1136.7m²/g, and its specific capacitance is370F/g at10mA/cm², what’smore important, the capacitance stability in the charge/discharge process have beenimproved a lot, the specific capacitance is323F/g at the end of1000cycles, onlydecreasing about9.3%.