Electrochemical\nEfficacy of a Ni<sub><i>x</i></sub>S<sub><i>y</i></sub>/WS<sub>2</sub> Composite as\nan Efficient Electrode Material for a High Performance Hybrid Supercapacitor\nand Aqueou

Transition\nmetal-based chalcogenide (TMX) has multiple\nvalence\nstates, a high surface area, excellent electronic conductivity, and\nelectrochemical activity with various applications. Nickel sulfide/tungsten\ndisulfide (NiS/Ni<sub>3</sub>S<sub>4</sub>/WS<sub>2</sub>) (NWS) composites\nare synthesized with three different metal ratios (1:1, 1:2, 2:1)\nby a two-step solvo-hydrothermal method. The binary NWS composites\nare enriched with numerous metal active sites to enhance their electrochemical\nbehavior. Half-cell configurations help analyze the electrochemical\nperformance of the NWS composite electrode material. Compared to the\nas-prepared samples, the NWS (1:1) composite electrode showed the\nhighest specific capacitance of 1,475 F g<sup>–1</sup> at a\nspecific current of 1 A g<sup>–1</sup>, respectively. The hybrid\nsupercapacitor (HSC) is fabricated using N-doped graphene (NG) as\nthe negative electrode and NWS (1:1) composite as the positive electrode\nwith an aqueous electrolyte of 3 M KOH. The fabricated NG//NWS (1:1)\ndevice exhibits a specific energy of 39.25 Wh kg<sup>–1</sup> with a specific power of 750 W kg<sup>–1</sup> at a specific\ncurrent of 1 A g<sup>–1</sup>. An NWS (1:1) composite is also\napplied in an aqueous Zn-Ni battery as a positive electrode and a\nzinc-deposited graphite sheet (Zn@GS) as a negative electrode, which\ndelivers a specific energy of 171 Wh kg<sup>–1</sup> at the\nspecific power of 5.7 kW kg<sup>–1</sup>.