A Facile One-Step Electrophoretic Deposition of Co−Ni-Layered Double Hydroxide Nanosheets for a High Performance Supercapacitor

Abstract

Herein, we report a facile and cost‐effective electrophoretic deposition (EPD) of Co−Ni‐ layered double hydroxide (Co−Ni LDH) nanosheets on a stainless steel substrate without the use of any additives and binders. The structural features and surface morphology of the LDH were studied by FTIR, Raman and X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), scanning electron and transmission electron microscopy (SEM & TEM) and energy dispersive X‐ray spectroscopy (EDX). The as‐prepared electrodes were assessed for their performance in electrochemical supercapacitors by both cyclic voltammetry and galvanostatic charge‐discharge methods. The Co:Ni feed ratio during deposition played a vital role in influencing the specific capacitance value. Electrochemical impedance spectroscopy (EIS) data indicate a favourable charge transport for the Co−Ni LDH prepared with a Co:Ni feed ratio of 2:1. The EPD parameters were optimized to maximize the electrode performance in the supercapacitor. A high specific capacitance of 1931 F g–1 at a discharge current density of 1.25 A g–1 has been obtained for a Co:Ni feed ratio of 2:1 which is quite comparable with the values reported in the literature. Moreover, the obtained specific capacitance value is higher than that of the electrophoretically deposited films of Co(OH)2 (756 F g–1) and Ni(OH)2 (281 F g–1). The protocol developed for the synthesis of Co−Ni‐LDH is easily adaptable for large scale synthesis making it viable for practical applications.

Nanoscale Composition Tuning of Cobalt–Nickel Hydroxide Nanosheets for Multiredox Pseudocapacitors

“…Among the various candidates for 2D transition metal hydroxides, cobalt-and nickel-based hydroxide compounds have attracted enormous attention as a promising electrode for supercapacitor materials, owing to their tunable interlayer spacing, excellent electrochemical redox behavior, and high expected capacitance values. 3,4 Moreover, it has been shown that bimetallic Co− Ni(OH) 2 exhibited enhanced electrochemical properties compared with monometallic hydroxides because of synergistic effects of double cations. 5−7 In typical two-step approaches for the synthesis of 2D metal hydroxide NSs, the first method involves a bottom-up mechanism wherein 2D NSs are directly synthesized by assembly at atomic or molecular scales in a gas or liquid medium using organic templates to form desired 2D shapes.…”

“…Typical transition metal oxides and hydroxides are promising supercapacitor electrode materials that are used because of their high chemical stability, compatibility, specific capacitance, and environmental friendliness. , In contrast to bulk transition metal oxides and hydroxides, their two dimensional (2D) counterparts can compensate for the weaknesses of bulk materials by offering short diffusion paths, high electronic conductivity, and large surface areas. Among the various candidates for 2D transition metal hydroxides, cobalt-and nickel-based hydroxide compounds have attracted enormous attention as a promising electrode for supercapacitor materials, owing to their tunable interlayer spacing, excellent electrochemical redox behavior, and high expected capacitance values. , Moreover, it has been shown that bimetallic Co–Ni­(OH) 2 exhibited enhanced electrochemical properties compared with monometallic hydroxides because of synergistic effects of double cations. − …”

Hierarchical Manganese–Iron-Layered Double Hydroxide Nanosheets for Asymmetric Supercapacitors

“…Among the various LDH structures, NiAl-LDH, NiCo-LDH, MnCo-LDH, and NiFe-LDH structures are widely used as supercapacitor electrodes as well as for catalysis applications [9][10][11][12]. Bagavathi et al fabricated Co-Ni LDH using the electrophoretic deposition technique, which produced a specific capacitance of 1931 Fg −1 [13]. They synthesized these nanostructures without any aid from additives and binders.…”

NiCoAl Ternary Metal Hydroxides Prepared by Fluorine Ion Assisted Electrodeposition Process for Long Lifespan Supercapacitor Electrodes

“…In comparison, electrodeposition has drawn huge attention as a substitution because it is a facile, rapid, and eco-friendly way. [46][47][48] We firstly doped slight inactive single-valence element Zinc into NiCo-LDHs through two consecutive electrodeposition processes only within 30 min. 49 By controlling the doping content of Zn 2+ at 2.9%, the composite electrode achieved the best performance with a high specific capacitance of 1749 F g −1 and ultralong lifespan with 89% capacitance retention after 40000 charge-discharge cycles.…”