Functionalized dodecyl sulfate ions on Co/Ni hydroxides: synergistic effect on supercapacitor electrode performance

The present investigation highlights the formation of dodecyl sulfate (SDS)-functionalized binary Co/Ni hydroxide using a facile sol–gel method. The effect of (SDS) surfactant ions on hydroxides was studied using X-ray diffraction and Fourier transform infrared spectroscopy. The nanoflakes and their vertically aligned uniform distribution were scrutinized by field-emission electron microscopy, high-resolution transmission electron microscope and atomic force microscopy. The developed metal hydroxides (Co-Ni-SDS) possessed maximum specific capacitance of 2765 F g–1 at current density of 5 A g–1 with retained capacity of ~ 88% after 5000 cycles. An asymmetric solid-state supercapacitor (ASC) device was fabricated with the best possible composition of metal hydroxide as positive and carbon black as negative electrode, which was utilized to brighten a commercial LED (1.8 V, 20 mA) for validation purposes. The efficiency of ASC was evaluated about 283 F g–1 by maintaining energy density of 88 Wh kg–1.