Reduced Graphene Oxide–Sodium Manganese Oxide Nanowire Nanocomposite Aerogels for Asymmetric Supercapacitors: Impact of Composite Concentration

Transition metal oxides are considered potential candidates for supercapacitor electrodes but often suffer from lower ionic diffusivity and poor electronic conductivity. Addressing these challenges requires the development of electrode materials with well-engineered architectures and precise designs. This research focused on fabricating nanocomposites by combining one-dimensional (1D) sodium manganese oxide (Na_0.4MnO₂) nanowires (NMO NWs) with a three-dimensional (3D) reduced graphene oxide aerogel (RGA). The NMO NWs are aligned and interconnected within the graphene layers, forming a 3D NMO/RGA composite (NRGA) matrix with excellent integration. NMO NWs increase the nanocomposite surface area by acting as spacers between graphene layers. The percentage of NMO NWs significantly influences the structural properties of the electrode, thereby affecting its supercapacitor performance. Notably, the RGA composite with a 40% loading of NMO NWs (N4RGA) achieved a specific capacitance of 576 F g^-1 at 6 mA cm^-1. The fabricated asymmetric supercapacitor (ASC) device demonstrated a potential of 1.8 V and achieved an energy density of 48.58 Wh kg^-1 at a power density of 222.2 W kg^-1, along with excellent cyclability. This study highlights a pathway for developing aerogel-based nanocomposites by integrating nanomaterials of varying dimensions, offering potential for advanced energy storage applications.