Effect of oxidant on the structural, morphological and supercapacitive properties of nickel hydroxide nanoflakes electrode films

• Synthesis of Ni(OH)2 and Ni(OH)2·NiOOH nanoflakes by using a K2S2O8 oxidant.
• Oxidant increases active surface area and electrical conductivity of the electrode.
• Oxidant-mediated Ni(OH)2·NiOOH electrode shows maximum supercapacitance of ~1257 F/g.

Nanostructured nickel hydroxide Ni(OH)2 electrode films were synthesized using a chemical bath deposition (CBD) method at 80 °C. The effect of an oxidizing agent potassium persulfate (K2S2O8) on the structural, morphological and supercapacitive properties of the Ni(OH)2 electrode has been investigated. The structural and morphological studies revealed that randomly oriented Ni(OH)2 nanoflakes are converted into vertically aligned dense Ni(OH)2·NiOOH nanoflakes after the addition of the K2S2O8 oxidant. The specific capacitance of the Ni(OH)2·NiOOH electrode is found to be ~1257 F/g which is significantly larger than that of the Ni(OH)2 electrode (~454 F/g). The oxidant-mediated Ni(OH)2·NiOOH electrode shows an improved capacitive retention. The significantly improved supercapacitor properties of the Ni(OH)2·NiOOH electrode are due to a combined effect of increased active area and enhanced electrical conductivity.