Comparison of our work with related studies in the literature.

Electrode material	Method of synthesis	Electrolyte	Sp. capacitance (F g−1), scan rate (mV s−1)/current density (A g−1)	Columbic efficiency (%) & cycles	Ref.
Fe2O3	Chemical bath deposition	1 M NaOH	178 F g−1, 5 mV	89% & 3000	43
α-Fe2O3	Self-assembly process	0.5 M Na2SO3	127 F g−1, 1 A g−1	80% & 1000	44
α-Fe2O3	Hydrothermal approach	1 M KOH	249 F g−1	93.6% & 2000	45
α-Fe2O3/rGO	Hydrothermal method	1 M KOH	255 F g−1, 0.5 A g−1	90% & 4000	46
Cu-Fe2O3/g-C3N4	Hydrothermal method	1 M Na2SO4	244.0 F g−1, 5 mV s−1	94.22% & 2000	In the present work