Hollow Bowl NiS @polyaniline Conductive Linker/Graphene Conductive Network: A Triple Composite for High-Performance Supercapacitor Applications.

The achievement of the outstanding theoretical capacitance of nickel sulfide (NiS ) is challenging due to its low conductivity, slow electrochemical kinetics, and poor structural stability. In this study, we utilize polyaniline (PANI) as a linker to anchor the NiS with a hollow bowl-like structure, uniformly dispersed at the surface of graphene oxide (GO)(NiS @15PG). The presence of PANI provides growth sites, resulting in a uniform and dense arrangement of NiS . This morphological modulation of NiS increases the contact area between the active material to electrolyte. Additionally, PANI effectively connects NiS with the conductive network of GO, which advances the electrical conductivity and ion diffusion properties. As a result, the R (charge transfer resistance) and Z (Warburg impedance) of NiS @15PG decrease by 82.61 % and 66.76 % respectively. This unique structure confers NiS @15PG with high specific capacitance (536.13 C g at 1 A g ) and excellent multiplicative property of 60.93 % at 20 A g . The assembled NiS @15PG//YP-50 supercapacitors (HSC) demonstrates an energy density (13.09 Wh kg ) at a high-power density (16 kW kg ). The capacity retention after 10,000 cycles at 5 A g is 86.59 %, indicating its significant potential for practical applications.