A one-pot synthesis of ZnS-NiS-NiS2 composite and its synergistic effect on different electrolytes for supercapacitor applications

Abstract

To date, owing to high molar conductivity and capacitance, metal sulfide–based electrodes have been constructed for supercapacitor applications. Supercapacitors (SCs) are known for their rapid charge–discharge rate and long-cycle durability. For the first time, a composite including zinc sulfide, nickel sulfide, and nickel disulfide (ZnS-NiS-NiS₂) was successfully produced using a one-pot solvothermal technique for supercapacitor applications in diverse electrolytes. XRD and FT-IR measurements revealed the construction of the prepared composite. SEM and HR-TEM investigations demonstrate that the produced material is possessed spherical. The ZnS-NiS-NiS₂ composite was studied for its specific capacitance in the presence of dissimilar electrolytes. In comparison to Na₂SO₄ (1 M) electrolyte and a blend of KOH (0.5 M)/Na₂SO₄ (1 M) electrolytes, the KOH (0.5 M) electrolyte achieves an exceptional specific capacitance of 179 F g⁻¹ at a current density of 1 A g⁻¹. The ZnS-NiS-NiS₂ electrode preserves 91% of its capacitance across 3000 cycles at 5 A g⁻¹ when using KOH (0.5 M) as an electrolyte. The synthesized ZnS-NiS-NiS₂ electrode can be employed in the future development of energy preservation.