α-Fe2O3 thin films by liquid phase deposition: low-cost option for supercapacitor

In the present study, iron oxide (alpha-Fe2O3) thin films with good adhesion on stainless steel substrates are deposited by liquid phase deposition (LPD) technique, which is additive and binder-free. Iron oxyhydroxide (FeOOH) thin films are formed by means of a ligand-exchange equilibrium reaction of metal-fluoro complex ions and an F(-)ions consuming reaction by using boric acid (H3BO3) as a scavenging agent. These films are annealed at 500 A degrees C to get alpha-Fe2O3 thin films. The transformation from hydrophobic to hydrophilic nature of the films is observed due to annealing. The films are characterized by different techniques. The alpha-Fe2O3 film is checked for electrochemical supercapacitive performance in Na2SO3 solutions of various concentrations. Specific capacitance is calculated from cyclic voltammetry at numerous scan rates (5-200) mV s(-1). The highest obtained value of specific capacitance is 582 F g(-1) at 5 mV s(-1) for 0.5 M Na2SO3 electrolyte. The maximum values of specific power and specific energy are 6.9 and 53.4 Wh kg(-1) from the charge-discharge curve at the current density 2 mA cm(-2) in 0.5 M Na2SO3 electrolyte.