Hydrothermal synthesis vs electrodeposition for high specific capacitance nanostructured NiO films

NiO nanostructured films were synthesized by hydrothermal and electrodeposition methods at different deposition temperatures. Films fabricated by different methods had similar crystalline structures, but different morphologies. The electrochemical properties of the NiO films were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy. For both fabrication methods, annealing was necessary to convert the films to NiO. After annealing at 300 degrees C, all films behaved as pseudocapacitors. The electrodeposited film fabricated at a deposition temperature of 70 degrees C on Ti foil exhibited a high value of pseudocapacitance (148 F/g at 100 mV/s CV scan rate), which suggests that electrodeposited films are promising for supercapacitor applications.