A nanocomposite electrode and supercapacitor thereof are disclosed. The nanocomposite electrode includes a substrate, at least one binding compound, at least one carbonaceous compound, and vanadium doped spinel ferrite nanoparticles (V-SFNPs). The V-SFNPs have a formula of CoxNi1-xVyFe2-yOz, wherein x=0.1-0.9, y=0.01-0.10, and z=3-5. The substrate is at least partially coated on a first side with a mixture comprising the V-SFNPs, the at least one binding compound, and the at least one carbonaceous compound. Two of the nanocomposite electrodes are combined to form the supercapacitor.