In this paper, a hybrid nanocomposite of cellulose fiber/multi-walled carbon nanotube (MWCNT)/reduced graphene oxide (rGO)/Cobalt oxide (Co3O4)/tin oxide (SnO2) is synthesized via a hydrothermal method for supercapacitor applications and characterized for their electrochemical performance and thermal stability. The morphology of the nanocomposites was characterized by using scanning electron microscope (SEM) and transmission electron microscope (TEM). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used to determine the chemical groups and crystal structure. Energy dispersive X-ray spectroscopy (EDX) confirmed the constitutional proportions of various elements in the composite. The electrode was fabricated from the nanocomposite and characterized by cyclic voltammetry (CV) that showed good cyclic stability with 88% capacitance retention after 1000 cycles and a capacitance of 215 F g−1 and 181 F g−1at a current density of 0.2 A g−1and 0.4 A g−1, respectively. The hybrid nanocomposite showed higher thermal stability than cellulose fiber/MWCNT and cellulose fiber/MWCNT/rGO composites. This simple, scalable and low-cost approach could open new opportunities for next-generation energy storage devices.