Fabrication of PPy/PANI/MnO2-based electrode and its electrochemical evaluation for supercapacitor applications

Abstract

A new PPy/PANI/MnO₂ polymer nanocomposite was synthesized through chemical oxidative polymerization process and fabricated as an efficient ternary electrode material for supercapacitors. All the synthesized nanomaterials were characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM/EDAX), High-resolution transmission electron microscopy (HR-TEM), Brunner-Emmett-Teller theory (BET), and X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical behavior of ternary PPy/PANI/MnO₂ electrode was initially tested in neutral (1 M Na₂SO₄), alkaline (1 M KOH) and acidic (1 M H₂SO₄) electrolytes through cyclic voltammetry (CV) at a scan rate of 5 mV/s to fix the electrolyte. PPy/PANI/MnO₂electrode exhibited the maximum specific capacitance of 303.92 Fg⁻¹ in 1 M Na₂SO₄ electrolyte than in alkaline (82.93 Fg⁻¹) and acidic (136.64 Fg⁻¹) electrolytes. From GCD studies, PPy/PANI/MnO₂ exhibited a maximum specific capacitance of 309.61 Fg⁻¹ at a current density of 5 A/g with 84% capacitive retention after 2500 charge/discharge cycles. Further, symmetric supercapacitor fabricated using PPy/PANI/MnO₂ electrodes exhibited a specific capacitance of 181.5 Fg⁻¹, energy density of 36.31 Wh/kg and power density of 2000 W/kg at 5 A/g. The low ESR (1.12 Ω) value exhibited by the fabricated supercapacitor and its capacitive retentivity of 79% at the end of 3000 charge/discharge cycles demonstrate its suitability for energy storage applications.