Fabrication of polypyrrole conductive matrix covered MnNi2O4 nanocomposite as a positive electrode material for asymmetric supercapacitor applications

Abstract

In this study, we successfully prepared a polypyrrole conductive matrix (PPY) covered manganese nickel oxide (MnNi₂O₄) nanocomposite via co-precipitation and a chemical oxidative polymerization route. The structural morphology of the as-prepared electrode materials was studied using FTIR, XRD, SEM, and XPS analysis. The specific surface area of the prepared MnNi₂O₄/PPY composite was found to be 68.40 m² g⁻¹, which facilitated the active migration of electrolyte ions. Supercapacitor measurements on the as-synthesized materials were performed through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements. From three electrode measurements, the MnNi₂O₄/PPY composite delivered a specific capacitance (C_sp) of 304 F g⁻¹ at a current density of 1 A g⁻¹. The charge storage contribution analysis of the MnNi₂O₄/PPY composite electrode showed 62.2% diffusion-controlled behavior and 37.8% surface-controlled behavior. The suitability of these composites was extensively studied as a positive electrode material for asymmetric supercapacitors in a widened operating voltage window of 1.6 V. Furthermore, the assembled MnNi₂O₄/PPY//AC asymmetric device had an energy density of 35.9 W h kg⁻¹ at a power density of 802.9 W kg⁻¹. These results open up promising applications of these materials in advanced energy storage.