Synthesis of Li-doped nickel oxide thin film electrodes for electrochemical capacitors using electrostatic spray deposition technique

Abstract

Thin film of Li-doped nickel oxide was prepared by the electrostatic spray deposition (ESD) technique onto a Pt coated silicon wafer and Pt coated alumina substrate with different deposition temperatures. Crystal structure, surface morphology and electrochemical properties of the LixNi1-xO film were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry. It is found that the deposition temperature had a significant impact on the structure, surface morphology and the number of electrochemically active site of the Li-doped nickel oxide and their corresponding electrochemical properties for the Li-doped nickel oxide film prepared by the ESD technique. The Li0.1Ni0.9NiO film deposited at 200°C exhibits the maximum specific capacitance of 251 F/g with a high rate capability in 1 M KOH solution. This relatively high specific capacitance of this film was originated from its unique highly porous surface morphology and amorphous structure.