Fig. 1. Schematic of successive ionic layer adsorption and reaction (SILAR) system of CoS deposition onto stainless steel substrate
Fig. 2. Digital photographs of the (a) CoS-50, (b) CoS-60, (c) CoS-70, and (d) CoS-80 samples deposited onto stainless steel substrate
Fig. 3. FESEM images of the (a) CoS-50, (b) CoS-60, (c) CoS-70, and (d) CoS-80 samples deposited onto stainless steel substrate
Fig. 4. X-ray diffraction pattern of the CoS-70 sample
Fig. 5. CV curves of CoS nanosheet at constant 3 M KOH electrolyte according to scan rates (5 mV/s, 10 mV/s, 20 mV/s, 50 mV/s, and 100 mV/s); (a) 50 cycles; (b) 60 cycles; (c) 70 cycles (d) 80 cycles.
Fig. 6. Galvanostatic charge-discharge curves of the (a) CoS-50, (b) CoS-60, (c) CoS-70, and (d) and CoS-8-electrodes at various current densities, (e) variation of the specific capacitance of the CoS-70 electrode at various current densities and (c) cycling stability of the CoS-70 electrode for 2000 charge-discharge cycles at 0.5 mA/cm2 current density.
Fig. 7. Nyquist plots of CoS electrodes; (a) CoS-50, (b) CoS-60, (c) CoS-70, and (d) CoS-80; Rs-equivalent series resistance; Rct - charge transfer resistance; W - Warburg impedance factor; CPE - constant phase element.
Table 1. Fitted electrochemical impedance parameters of the CoS-70 electrode prepared with the 70 SILAR cycles
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