Comparative studies on MWCNTs, Fe2O3 and Fe2O3/MWCNTs thin films towards supercapacitor application

An attempt has been made to synthesize multiwall carbon nanotubes (MWCNTs), Fe2O3, and Fe2O3/MWCNTs through a simple and cost-effective route onto a stainless steel (SS) substrate. The 'dip and dry' coating method was used for MWCNTs, whereas the successive ionic layer adsorption and reaction (SILAR) method was used for Fe2O3. Thin films were characterized using structural and surface morphological studies by XRD, FESEM and TEM. The results showed that hematite Fe2O3 nanoparticles with a particle size of less than 10 nm were uniformly coated onto the surface of MWCNTs. Comparative investigations have been made for MWCNTs, Fe2O3, and Fe2O3/MWCNTs as supercapacitive electrode materials with the aid of scan rate, cyclic voltammetry, charge-discharge studies, energy density, power density and stability. Among the three thin films, the Fe2O3/MWCNTs hybrid thin film electrode exhibited a high specific capacitance of 431 F g(-1) at a scan rate of 5 mV s(-1) and a high energy density of 38 W h kg(-1) with a power density of 800 W kg(-1) in 1 M Na2SO3 electrolyte solution. The detailed analyses are reported herein.