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High‐temperature oxidation of aniline to highly ordered polyaniline–sulfate salt with a nanofiber morphology and its use as electrode materials in symmetric supercapacitors
Author(s) -
Palaniappan Srinivasan,
Sydulu Singu Bal,
Prasanna Taneeru Lakshmi,
Srinivas Pabba
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.33091
Subject(s) - polyaniline , ammonium persulfate , cyclic voltammetry , dielectric spectroscopy , aniline , supercapacitor , materials science , nanofiber , sulfuric acid , chemical engineering , electrochemistry , electrode , inorganic chemistry , chemistry , nanotechnology , composite material , organic chemistry , polymerization , polymer , engineering , metallurgy
In this study, for the first time, aniline was oxidized by ammonium persulfate (APS) at higher temperatures without any protic acid, and APS acted as an oxidizing agent and a protonating agent. During the oxidation of aniline by APS, sulfuric acid formation occurred, and the sulfuric acid was incorporated into polyaniline (PANI) as a dopant. PANI–sulfate samples were characterized by IR spectroscopy, X‐ray diffraction, and scanning electron microscopy techniques. In this methodology, a highly ordered PANI–sulfate salt (H 2 SO 4 ) with a nanofiber morphology was synthesized. Interestingly, a PANI base was also obtained with a highly ordered structure with an agglomerated netlike nanofiber morphology. PANI–H 2 SO 4 was used as an electrode material in a symmetric supercapacitor cell. Electrochemical characterization, including cyclic voltammetry (CV), charge–discharge (CD), and impedance analysis, was carried out on the supercapacitor cells. In this study, the maximum specific capacitance obtained was found to be 273 F/g at 1 mV/s. Scan rate from cyclic voltammetry and 103 F/g at 1 mA discharge current from CD measurement. Impedance measurement was carried out at 0.6 V, and it showed a specific capacitance of 73.2 F/g. The value of the specific capacitance and energy and power densities for the PANI–H 2 SO 4 system were calculated from CD studies at a 5‐mA discharge rate and were found to be 43 F/g, 9.3 W h/kg, and 500 W/kg, respectively, with 98–100% coulombic efficiency. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011