Influence of solvents in the preparation of cobalt sulfide for supercapacitors

Abstract

In this study, cobalt sulfide (CoS) electrodes are synthesized using various solvents such as water, ethanol and a combination of the two via a facile chemical bath deposition method on Ni foam. The crystalline nature, chemical states and surface morphology of the prepared CoS nanoparticles are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transition electron microscopy. The electrochemical properties of CoS electrodes are also evaluated using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. When used as an electrode for a supercapacitor, CoS prepared with ethanol as a solvent exhibits a capacitance of 41.36 F g−1 at 1.5 A g−1, which is significantly better than that prepared using water and water/ethanol-based solvents (31.66 and 18.94 F g−1 at 1.5 A g−1, respectively). This superior capacitance is attributed to the ideal surface morphology of the solvent, which allows for easy diffusion of electrolyte ions into the inner region of the electrode. High electrical conduction enables a high rate capability. These results suggest that CoS nanoparticles are highly promising for energy storage applications as well as photocatalysis, electrocatalysis, water splitting and solar cells, among others. These results show that CoS is a promising positive electrode material for practical supercapacitors.

Potential transition and post-transition metal sulfides as efficient electrodes for energy storage applications: review

“…In the past few years, transition metal sulfide-based nanomaterials have been extensively studied in supercapacitors, 41–43 solar cells, 44,45 hydrogen production, 46 lithium-ion batteries, 47 and catalytic 48,49 applications. Furthermore, transition and post-transition metal sulfides (TMSs) have attracted attention due to their potential as pseudocapacitive materials for capacitors owing to their high specific capacitance, low cost, large global abundance, 50–54 greater conductivity than their oxide and hydroxide counterparts, 55,56 and rich redox reactions. In this scenario, a promising BiVO 4 –PbO x heterostructured photocapacitive system was reported with a specific capacitance of 6 mF cm −2 at a high open circuit potential of 1.5 V vs. reversible hydrogen electrode (RHE).…”

Fabrication of Hierarchical NiMoO4/NiMoO4 Nanoflowers on Highly Conductive Flexible Nickel Foam Substrate as a Capacitive Electrode Material for Supercapacitors with Enhanced Electrochemical Performance

“…SCs can provide a clean and efficient emerging storage technology to help solve the global and environmental energy crises [11]. Generally, energy storage in SCs takes place via two methods: electrochemical double layer capacitors (EDLCs) and pseudocapacitors (PCs or redox capacitors) [12,13]. In EDLCs, the capacitance is due to ion adsorption and desorption at the surface of the carbon electrode and redox electrolyte, whereas in PCs, the energy is stored in reversible faradaic redox reactions taking place at the electrolyte-electrode interface [14].…”

Facilely Synthesized NiCo2O4/NiCo2O4 Nanofile Arrays Supported on Nickel Foam by a Hydrothermal Method and Their Excellent Performance for High-Rate Supercapacitance

“…Over the last few decades, a range of energy storage devices, such as solar cells, batteries, lithium-ion batteries, electrochemical capacitors, fuel cells, and supercapacitors (SCs), have been reported [4]. Among the above energy storage devices, SCs have considerable potential and are used widely in storage devices owing to their rapid charge-discharge cycle performance, outstanding cyclability, eco-friendly nature, long cycling life span, and high rate abilities [5][6][7]. Various materials for faradic redox reactions (pseudocapacitors (PCs), such as Co 3 O 4 , NiO, MnO 2 , and RuO 2 , have been used as electrodes to achieve high energy capability for SCs [8,9].…”