Engineering iron–nickel nanostructures on the surface of functionalized nitrogen-doped graphene composite for high-performance supercapacitors

This study presents the development of a novel three-dimensional nitrogen-doped graphene/iron-nickel (3DNG/FeNi) composite as a high-performance electrode material for supercapacitors. The composite was synthesized using a simple sol-gel method followed by pyrolysis, exhibiting excellent electrochemical properties. The 3D nitrogen-doped graphene scaffold (3DNG), synthesized with azodicarbonamide as a nitrogen source and a porosity enhancer, provides a highly porous and conductive framework for Fe–Ni nanoparticle integration. The synergistic interaction of 3DNG and Fe–Ni nanoparticles enhanced the overall electrochemical performance, including high specific capacitance, excellent rate capability and superior cycling stability. The as-prepared asymmetric supercapacitor device that utilizes the 3DNG/NiFe composite as the positive electrode and commercial Vulcan carbon as the negative electrode, demonstrates an impressive energy density of 35.4 Wh kg⁻¹ and a power density of 14 kW kg⁻¹. These results highlight the potential of the 3DNG/NiFe composite as a promising electrode material for advanced energy storage devices.