Sulfur and nitrogen co-doped Ni/Co carbide 3D polyhedron nanoparticles with hollow core for hybrid supercapacitors

The methodologies for the synthesis of core-shell multilayered morphologies are being intensely explored. Following such scenarios, we report the fabrication of sulfur (S) and nitrogen (N) co-doped nickel/cobalt carbide (S,N@Ni/Co–C) hollow (carbon matrix) polyhedral nanoparticles (PNPs) by facile solvothermal and sulfurization process. The main objective of this research is to study the anomaly behind the structural deformation of the PNPs during the annealing and to propose a relevant method to preserve them by enhancing their abilities. Additionally, the electrochemical properties of the S, N@Ni/Co–C/nickel foam (NF) electrode are optimized and examined, exhibiting a high areal capacity of 563.3 μAh cm⁻² and a notable cycling retention of 96 % at 7 mA cm⁻² for 5000 cycles in a three-electrode system. Furthermore, the optimized electrode is employed as a positive electrode along with an activated carbon-coated NF as a negative electrode to fabricate a hybrid supercapacitor device which delivers a maximum energy density of 118.9 μAh cm⁻² and a maximum power density of 7000 μA cm⁻². Finally, it is used as a power source to drive a few real-time electronic devices, especially safety E-bands.