Designing hierarchical S and P coordinated Co-Ni bimetallic nanoparticles for enhanced supercapacitor electrode

Here, a unique sulfurization/phosphorylation transformation method was used to create S-P-CoxNiy, a Co-Ni bimetallic nanoparticle with S and P coordinated. The electrode had higher capacitive capabilities due to its unique structure and synergistic component. The highest performance was revealed by the as-obtained S-P-CoxNiy with the 1:4 Co: Ni molar ratio (S-P-Co1Ni4), as seen by its specific capacitance. The S-P-Co1Ni4 electrode developed a 1739.3 F g-1 specific capacitance at a 1 Ag-1 current density and strong cycle stability with retention of 92.6% after 10,000 cycles. These electrochemical results were superior to parent mono -phosphates (Co1Ni4P, 1223.2 F g-1, 88.3%), monosulfides (Co1Ni4S, 867.9 F g-1, 79.3%) and other derived counterparts (Co1Ni4O, 674.7 F g-1, 81.8%). It is shown that the high conductivity of sulfur, high stability of phosphide, multivalent states of nickel and cobalt, and tremendous synergy all contributed significantly to the excellent performance of S-P-Co1Ni4. Also, the built AC/S-P-Co1Ni4 asymmetric supercapacitor provided a high energy density of 42.7 Wh kg-1 at a power density of 703.9 W kg-1 and a good specific capacitance of 156.89 F g-1 at 1 Ag-1. This is in addition to amazing stability of 90.5% after 10,000 cycles at 10 A g-1. In this case, the improved electrochemical performance of the developed electrode material indicates that it holds great promise as a material for use in energy storage devices.(c) 2023 Elsevier B.V. All rights reserved.