Influence of CTAB on morphology, structure, and supercapacitance of β-Ni(OH)2

Abstract

Cetyltrimethylammonium bromide (CTAB) was used as surfactants to modify the crystallization of β-Ni(OH)2 via a simple ammonia-evaporation/CTAB-induced method onto nickel foam by using a mixed aqueous solution of nickel nitrate, CTAB, and ammonia. Their structure and surface morphology are characterized by X-ray diffraction and scanning electron microscopy. The SEM images show changes in the microstructure of β-Ni(OH)2, and the XRD patterns exhibit a much higher relative diffraction intensity of (1 0 0) peaks with the addition of CTAB. The effects of CTAB content on the electrochemical behaviors of β-Ni(OH)2 are investigated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The results demonstrate that the modified β-Ni(OH)2 electrode has better electrochemical performance, such as better reaction reversibility, higher proton diffuse coefficient, higher specific capacity, and better cyclic stability. Importantly, when the CTAB content in the initial solution was 0.03 g, the results show a drastic improvement in the capacitive characteristics of β-Ni(OH)2 with a specific capacitance increases from 386 to 1,019 F g−1 at a high charging/discharging current density of 6 A g−1.