Effect of morphology on supercapacitive properties of chemically grown β-Ni(OH)2 thin films

Different nanostructures of β-Ni(OH)2 have been successfully developed using simple chemical bath deposition (CBD) method from different nickel precursors. Effect of different nickel precursors on structural, morphological and supercapacitive properties of β-Ni(OH)2 thin films have been investigated. The formation of nanocrystallinity and β-phase of Ni(OH)2 are confirmed by X-ray diffraction and FTIR studies. Scanning electron microscope study revealed the formation of multilayer nanosheets, up grown nanofalkes and interconnected, macroporous; honeycomb-like structures of β-Ni(OH)2 films. BET analyses showed that nanoflakes and honeycomb like structure have high surface area of 75 and 65 m2 g−1 with micro and mesopores network. The electrochemical supercapacitor properties of the β-Ni(OH)2 films are examined using cyclic voltammetry (CV) and galvanostatic charge discharge studies. The β-Ni(OH)2 films showed pseudocapacitive behavior with maximum supercapacitance of 462 F g−1 in 2 M KOH electrolyte, suggesting its potential application in electrochemical supercapacitors.

Graphical abstractFig. (a) shows the width of the nanoflake and wall of the honeycomb like structure which suggest that width of nanoflake is smaller (27 nm) than the wall of honeycomb like structure (38 nm). The maximum supercapacitance of 462 F g−1 is obtained at 5 mV s−1 scan rate for the mass loading of 0.0018 g cm−2. Inset of Fig. (b) shows high magnified SEM image of NiOH:S film, from which it is seen that pore size is approximately 1–2 μm. Hence further NiOH:S electrodes are used to study the effect of scan rate on supercapacitance of β-Ni(OH)2 thin film.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Simple and inexpensive synthesis of β-Ni(OH)2 thin films. ► Morphological evolution. ► Application in supercapacitance with maximum value of 462 F g−1. ► High stability and charge/discharge efficiency.