Effect of cobalt doping on electrochemical properties of sprayed nickel oxide thin films

Abstract

The nickel oxide (NiO) thin films are prepared with different level of cobalt (Co) doping (2–10 wt%) on conducting (FTO) by using spray pyrolysis technique. The effect of Co doping on the microstructure and electrochemical performance of NiO thin film electrodes are thoroughly investigated. The X-ray diffraction results exhibited the polycrystalline cubic NiO structure with (111) as preferential orientation. The XPS analysis revealed existence of Co in NiO thin films. The field emission scanning electron microscopy (FE-SEM) of 4% Co:NiO thin films presented porous surface morphology. The maximum specific capacitance 835F. g−1 is attained at scan rate of 5 mV s−1 from cyclic voltammetry in 2 M KOH electrolyte for 4% Co doped NiO thin film. Further, exhibited the maximum specific capacitance of 246.80F.g−1 at current density of 0.2 mA/cm2 with 96% capacity retention after 1000 cycle.

Keywords

• Spray pyrolysis
• NiO
• Cyclic voltammetry
• Cobalt doping
• Electrochemical supercapacitors