Synthesis, characterization, and study of the supercapacitive performance of NiO nanoplates prepared by the cathodic electrochemical deposition-heat treatment (CED-HT) method

NiO nanoplates were prepared through a method base on cathodic electrochemical deposition-heat treatment. The deposition mechanism of the hydroxide precursor (i.e. Ni(OH)(2)) during the CED step, and final oxide formation during the HT step were specified. The structural and morphological evolutions by XRD, SEM and TEM confirmed the production of pure beta-Ni(OH)(2) nanoplates and cubic crystalline NiO nanoplates as the CED and HT products, respectively. The supercapacitive performance of the prepared NiO nanoplates was further studied by techniques of cyclic voltammetry and galvanostatic charge-discharge within the potential window of -0.1 to 0.5 V in 1 M KOH electrolyte. The measurements revealed that the nanoplates have high reversibility (Delta E-p = 22 mV), high specific capacitance (1345 F g(-1) at the scan rate of 2 mV s(-1)) and proper long-term cycling stability of 89.1 % capacity retention after 3000 cycling at the current density of 1 A g(-1).