Split cell electrode supercapacitor

1 . A split cell nanocomposite electrode supercapacitor, comprising:

a first electrode, a second electrode and a separator, wherein the separator is between the first electrode and the second electrode and the first electrode, the second electrode and the separator form a symmetrical split cell layered structure wherein the first electrode, the second electrode and the separator are flat and circular,

wherein the first electrode and the second electrode each comprise:

a substrate made from aluminum;

polyvinylidene fluoride as a binding compound;

at least two carbonaceous compounds selected from the group consisting of graphite, activated carbon, reduced graphene oxide, and carbon black; and

vanadium doped spinel ferrite nanoparticles (V-SFNPs);

wherein the V-SFNPs have a formula of Co x Ni 1-x V y Fe 2-y O z ;

wherein x=0.1-0.9, y=0.01-0.10, and z=3-5;

wherein the substrate is at least partially coated on a first side with a mixture comprising the V-SFNPs, the binding compound, and the carbonaceous compounds.

2 . The split cell nanocomposite electrode supercapacitor of claim 1 , wherein the V-SFNPs have:

a substantially spherical shape;

an average size of 10-1000 nm.

3 . The split cell nanocomposite electrode supercapacitor of claim 1 , wherein the V-SFNPs comprises:

20-30 wt % oxygen, 1-10 wt % vanadium, 40-50 wt % iron, 10-20 wt % cobalt, and 10-20 wt % nickel, based on the total weight of the oxygen, vanadium, iron, cobalt, and nickel.

4 . The split cell nanocomposite electrode supercapacitor of claim 1 , wherein the mixture comprises:

1-20 wt. % of the V-SFNPs; and

80-99 wt. % of the binding compound, and the carbonaceous compounds based on the total weight of the V-SFNPs, the binding compound, and the carbonaceous compounds.

5 . The split cell nanocomposite electrode supercapacitor of claim 1 , having:

85-92 wt % carbon, 5-10 wt % oxygen, 0.1-2 wt % vanadium, 0.5-2 wt % iron, 0.5-1 wt % cobalt, and 0.5-1 wt % nickel, based on the total weight of the carbon, oxygen, vanadium, iron, cobalt, and nickel.

6 . The split cell nanocomposite electrode supercapacitor of claim 1 , wherein the V-SFNPs are made by a method comprising:

mixing a cobalt (II) salt, a nickel salt, an iron (III) salt, and a vanadium (III) salt in water to form a mixture;

adjusting the pH of the mixture to 10-12 with a base to form a basic mixture;

heating the basic mixture to 150-200° C. for 10-20 hours to form a powder; and

washing the powder with water and drying at a temperature of 60-80° C. to form the V-SFNPs.