An iron oxide based-electroactive IoNanofluid with a high dielectric constant, high stability and low viscosity was synthesized from ferrous sulphate heptahydrate via a facile microwave assisted one-step route in 1-butyl-4-methylpyridinium chloride. The IoNanofluid exhibited CE coupled faradaic redox reactions involving reversible chemical reaction and reversible electron transfer steps. A transition from diffusion controlled to surface controlled capacitive processes was observed at varying scan rates. The efficiency of the charge-discharge process was greater than 94% even after 100 cycles.