Nanostructured NiO for electrochemical capacitors: synthesis and electrochemical properties

A single phase nanostructured nickel oxide (NiO) crystalline product was synthesized via a simple solvothermal synthesis protocol by using nitrate-citrate precursor having Ni(NO3)(2) as starting material. The thermal decomposition of the as-formed gel precursor leading to the formation of crystalline NiO was monitored by TG analysis under ambient conditions. The as-prepared product was subjected to thermal treatment at 400 C for 1 h in air, exhibited a single phase cubic structure as confirmed by XRD and the nanostructure of the product was characterized by FE-SEM and HR-TEM/SAED analysis. It is thus confirmed that the particle size of the product was found to be within 7-15 nm range. The rate-dependent cyclic voltammetry reveals the pseudocapacitive behavior of the product when employed as working electrode in a three-electrode electrochemical cell containing 1 M KOH aqueous electrolyte with platinum (pt) and saturated calomel electrode (SCE) as counter and reference electrodes, respectively, yielding a capacitance of similar to 200 F g(-1).