Electrochemical synthesis and potential electrochemical energy storage performance of nodule-type polyaniline

Nodule-type polyaniline (PAni) has been successfully electrosynthesized onto conducting substrate and envisaged in electrochemical supercapacitor (ES) application as a potential energy storage electrode. Various bands are confirmed from the X-ray photoelectron and Fourier transform infrared spectra. Each nodule is of ∼100–200 nm in length and 20–80 nm in diameter. The ∼45° surface water contact angle with water of PAni surface can be beneficial for accessing an entire electrode area with minimum interfacial resistance loss when is in contact with the aqueous electrolyte for ES application. The PAni nodule-type electrode when electrochemically characterized using cyclic-voltammetry and galvanostatic charge–discharge measurements has demonstrated a specific capacitance of ∼508 F g⁻¹, a specific energy of 32.12 W h kg⁻¹, a specific power of 13.39 kW kg⁻¹ and a Coulombic efficiency of 100% in 1 M H₂SO₄ electrolyte solution. An occurrence of 70% retention of initial capacity even after 5000 cycles is supporting for energy-storage application. Two separate redox reaction behaviors are confirmed in the discharge measurement.