Galvanostatic deposition of polypyrrole in the presence of tartaric acid for electrochemical supercapacitor

• Polypyrrole coatings were synthesized in the presence oftartaric acid and Triton X-100.
• The specific capacitance of coating on pencil graphite electrode is 794 F g−1.
• The power density of coating on passivated 316Ti SS is 36.3 kW kg−1 at 15 mA cm−2.
• These coatings have potential for low-cost and high-performance energy storage.

Galvanostatic deposition of tartrate–doped polypyrrole (PPy) is carried out on platinum foil in acetonitrile solution with tartaric acid, tetrabutylammonium tetrafluoroborate and Triton-X 100 for supercapacitor studies. The effect of substrate is studied by comparing the results obtained by using platinum, stainless steel and pencil graphite electrodes. The capacitive performance of the coatings are evaluated in an H2SO4/water medium by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge methods. Based on the charge–discharge results obtained, the tartrate–doped PPy coatings represent a high specific capacitance of 794 F g−1 (areal capacitance of 238 mF cm-2) and a high energy density of 105 Wh kg-1 on pencil graphite electrode, and a high power density of 36.3 kW kg-1 on 316Ti stainless steel electrode. High values may be attributed to the incorporation of tartaric acid via hydrogen bonding, and/or tartrate anion as dopant together with the tetrafluoroborate anion. Besides, Triton X100 provides high porosity and therefore high surface area.