Electrodeposition mode effects on the electrochemical performance of cobalt sulfide material for supercapacitors

This study investigates cobalt sulfide (CoS) as a promising electrode material for high-performance energy storage devices. A one-step potentiostatic deposition method was used to create binder-free, nanostructured CoS electrodes on FTO substrates. By employing both direct and pulse potentiometry to deposit CoS films from a nitrate solution and thiourea, crucial insights into optimizing the deposition process for better electrode performance are provided. The systematic evaluation of these methods, particularly pulse deposition, is rarely explored for CoS electrodes. Cyclic voltammetry, galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy (EIS) were used to assess the electrochemical performance. When the pulse deposition mode was applied, a specific capacitance of 292.2 Fg⁻¹ at a scan rate of 5 mV s⁻¹ was achieved for the CoS (P) film, which is sufficient to meet the necessary standard; accordingly, it is confirmed that the CoS (P) film is a good alternative for electrode application. Additionally, this film demonstrated 84.21% capacity retention after 1000 galvanostatic charge–discharge cycles with a current density of 5 Ag⁻¹.