Negative capacitance for polyaniline: An analysis via electrochemical impedance spectroscopy

Wei Chih Chen, Ten Chin Wen, A. Gopalan

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


Polyaniline (PANI) films were electrodeposited on Pt electrode by cyclic voltammetry using an anodic switching potential of 0.90 V, which favored benzoquinone (BQ) as side product. The redox interactions between BQ and PANI were analyzed through electrochemical impedance spectroscopy (EIS). PANI films of different thickness were subjected to different applied potentials and impedance spectra were recorded. PANI films were found to show negative capacitance (inductive loop) in the potential range of 0.50-0.70 V. A redox mechanism involving the role of BQ to impart negative capacitance to PANI is given and supported by the results from X-ray photoelectron spectroscopy (XPS). An equivalent circuit including an inductor element (L) is found to fit perfectly with data from EIS. The effect of thickness of PANI on L-value is elucidated and discussed.

Original languageEnglish
Pages (from-to)179-189
Number of pages11
JournalSynthetic Metals
Issue number2
Publication statusPublished - 2002 Apr 30

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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