A Study of Chemically Synthesized Polypyrrole as Electrode Material for Battery Applications

Abstract

We have studied the behavior of a chemically synthesized polypyrrole as electrode material. The different electrochemical methods that we have used for this characterization, namely, cyclic voltammetry, ac impedance measurements, and cyclic chronopotentiometry, have evidenced the role of the low frequency capacitance Cnormals characteristic of the doped state of polypyrrole. This capacitance seems independent of the synthesis conditions of the polymer, and we show that it partially explains the large value of the total charge false(Cnormalm>100 normalAh/normalkgfalse) stored in this polypyrrole. Analyzing the effect of residual water in the polymer, we show that a water content of about 3% (w/w) increases the total charge Cnormalm and lowers the redox potential E0 . A quasi linear relationship has been found between E0 and Cnormalm , the massic capacity: Cnormalm increases when E0 decreases. This relation can be also attributed to the charging of the capacitance Cnormals:Qnormalcs=Cnormals false(Enormald−E0false) , where Enormald is the degradation potential. We discuss the origin of this capacitance Cnormals .

Nickel(ii) tetra-aminophthalocyanine modified MWCNTs as potential nanocomposite materials for the development of supercapacitors

“…These SC values are indicative of strong deviation from the data obtained from the galvanostatic method. This strong discrepancy has also been observed by several workers for conducting polymeric substances, [35][36][37][38][39][40] and the origin of which has long been a subject of some controversy for more than two decades. For example, Murray and co-workers 35 have suggested the involvement of some physico-chemical heterogeneities; Tanguy and co-workers 37 attributed such phenomenon to ''deeply trapped'' counter ions which remain immobile during impedance experiment; while Kalaji and Peter 39 described it as the consequence of slow conformational changes occurring in the polymer network.…”

Electrochemical Characterization of Electronically Conductive Polypyrrole on Cyclic Voltammograms

“…The origin of such large capacitance in polymer films has been discussed in detail by Tanguy et al (26) and Mermilliod et al (27) The behavior observed is similar to that of a capacitor with very high capacitance and is due to the highly porous structure of polypyrrole films (16). The polypyrrole film is very stable between -0.8 and +0.8 V vs. SCE.…”

Thermal Behaviour of Chemically Synthesized Polyanilines/Polystyrene Sulphonic Acid Composites

“…It has also been proposed that the incorporation of side groups into the main chain [12], grafting of the conducting PANI chain to a non-conductive polymer [13] and electrochemical polymerization of aniline in a polymer matrix [14] improve their processibility and thus broaden their applicability. A large amount of PANI-inorganic composites like PANI/V 2 O 5 [15], PANI/TiO 2 [16][17][18], PANI/CdS [19], PANI/graphite oxide [20] and PANI/clay [21,22], etc have been synthesized and studied to enhance the overall Silver sulphate, ammonium persulphate, HCl and H 2 SO 4 were used as received. Double distilled water was deionized by Millipore used throughout the studies.…”