Synthesis of cobalt-doped nickel sulfide nanomaterials with rich edge sites as high-performance supercapacitor electrode materials

In this study, cobalt-doped nickel sulfide nanomaterials are synthesized. The experimental results show that cobalt is successfully doped into the lattice of NiS₂. Co-doping causes the hollow sphere sulphides to break down and favors the formation of Ni_xCo_1−xS₂ nanostructures with high-density active edge sites. The Ni_0.75Co_0.25S₂ sample exhibits a high specific capacitance of 2141.9 F g⁻¹ at a current density of 2 A g⁻¹ due to its fluffy characteristics and edge site-enriched nanostructure. The asymmetric supercapacitor based on Ni_0.75Co_0.25S₂ exhibits a high energy density (54.9 Wh kg⁻¹) and stable cycling durability with 85.1% capacitance retention after 4000 cycles.