Dumping of solid waste and draining of energy resources have become an escalating global issue by affecting the world's ecology and economy through environmental pollution and fuel crisis. The primary concern of this investigation is to transform solid waste to clean energy conversion and storage material by developing a solid waste-derived carbon/metal oxide composite electrode for supercapacitors. For this purpose, we use infant-urinated waste diapers from the major municipality waste as a nitrogen-doped carbon source to develop a facile and cost-effective electrode material. The presence of urea/uric acid in the urinated diaper can contribute nitrogen atoms to carbon suitable for enhancing the electrical conductivity of the carbon electrode. NiO act as pseudocapacitor material for compensating the shortage of volumetric and gravimetric performance in carbon. The structural and chemical properties of solid waste-derived carbon fibers-trapped nickel oxides (NiO@SW-CFs) were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectrum (XPS), and nitrogen adsorption-desorption isotherms. Electrochemical studies on NiO@SW-CFs were performed using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. NiO@SW-CFs exhibited a specific capacitance of 356 F g(-1) at a discharge current of 2 A g(-1) with robust cycle stability after 5000 cycles with a current density of 10 A g(-1). The synergic effect of NiO, N, and porous carbon proves NiO@SW-CFs as an excellent candidate for the future high-performance energy conversion and storage systems. This study offers a green approach for the development of environmentally favorable potential carbon electrodes, by converting solid waste to clean energy.