Synthesis and characterization of Ru doped CuO thin films for supercapacitor based on Bronsted acidic ionic liquid

The synthesis of nanostructured ruthenium (Ru) doped copper oxide (CuO) thin films by colloidal solution method and ionic liquid are presented. The prepared colloidal solution was spin coated on the stainless steel substrates. The coated films were used to measure the specific capacitance in the task specific Bronsted acidic that is in 3-carboxymethyl-1-methylimidazolium bisulfate [CMIM] [HSO4] ionic liquid (IL). Further, the films were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman) and cyclic voltammetry (CV). The Ru doped CuO films exhibit higher specific capacitance, Csp (Csp = ratio of average current in CV and a product of scan rate and mass deposited on the film) with the larger potential window as compared to undoped CuO film. The highest Csp of 406 F g−1 was observed for 15 volume percent of Ru doping concentration. This is the first successful step towards development of ecofriendly CuO based supercapacitors in task specific IL synthesized by green technology.