Synergistic integration of δ-MnO2/rGO composite electrode for enhanced electrochemical performance in supercapacitor applications

• δ-MnO 2 /rGO composite synthesized via simple hydrothermal method. • MnO 2 nanoflowers uniformly distributed on rGO surface. • TEM, XPS, Raman, and FTIR confirmed structure and composition. • BET analysis showed enhanced mesoporosity for better ion transport. • Symmetric device achieved 57.3 Wh/kg energy and 0.625 kW/kg power density. Transition metal oxides (TMOs), with reversible oxidation states, are attractive for supercapacitor electrodes. A nanocomposite of reduced graphene oxide (rGO) and δ-MnO 2 nanoflowers was synthesized via hydrothermal oxidation. TEM confirmed uniform MnO 2 distribution on rGO, and XPS verified oxidation states of Mn, O, and C. Raman and FTIR analyses revealed structural and functional groups. BET analysis showed enhanced meso -porosity, improving ion transport and electrolyte access. Improved wettability was confirmed by contact angle measurements. TGA-DTA indicated superior thermal stability of the composite. Electrochemical testing showed enhanced performance of δ-MnO 2 /rGO over pure δ-MnO 2 . CV demonstrated increased redox activity, and GCD showed a specific capacitance of 445.2 F/g for the composite compared to 233.3 F/g for δ-MnO 2 . A symmetric supercapacitor using δ-MnO 2 /rGO delivered 114.6 F/g at 1 A/g. EIS showed lower charge transfer resistance. The device achieved an energy density of 57.3 Wh/kg and power density of 0.625 kW/kg, highlighting its supercapacitor potential.