Composition-Dependent Electrochemical Performance of rGO-MnO2-PPy Nanocomposites in Acidic and Neutral Electrolytes

English (OpenAlex)

The demand for supercapacitor electrode materials with high specific capacitance, enhanced energy density, and superior power capability continues to increase. In addition to superior capacitance, electrode materials are required to deliver high energy density, cycling stability, and rate capability. In this study, we produced a rGO-MnO2-PPy nanocomposite using a facile two-step method. First, rGO-MnO2 was produced by hydrothermal synthesis. Subsequently, the rGO-MnO2-PPy nanocomposite was obtained through the polymerization and coating of polypyrrole (PPy) on the rGO-MnO2 surface. The electrochemical characterization of the electrodes was carried out in both Na2SO4 and acidic H2SO4 electrolytes using a two-electrode configuration. Benefiting from the synergistic interaction among its constituents, the nanocomposite exhibited specific capacitance of 345.87 and 220.16 F g−1 at 0.5 A g−1 in 0.5 M Na2SO4 and 1 M H2SO4 electrolytes, respectively. In addition, the ternary nanocomposite electrode exhibited good rate capability, retaining 81.03% and 72.03% of its specific capacitance over a current density range of 0.5–5 A g−1 in 0.5 M Na2SO4 and 1 M H2SO4 electrolytes, respectively. After 5000 galvanostatic charge–discharge cycles, the electrode showed excellent cycling stability, maintaining 88.85% and 86.08% of its initial capacitance in 0.5 M Na2SO4 and 1 M H2SO4 electrolytes, respectively. The rGO-MnO2-PPy nanocomposite symmetric cell delivered power density of 1421.97 W kg−1 and energy density of 8.65 Wh kg−1, highlighting its promise as an electrode material for next-generation supercapacitors.