Hollow Bowl NiS₂ @polyaniline Conductive Linker/Graphene Conductive Network: A Triple Composite for High-Performance...

The achievement of the outstanding theoretical capacitance of nickel sulfide (NiS₂ ) 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 NiS₂ with a hollow bowl-like structure, uniformly dispersed at the surface of graphene oxide (GO)(NiS₂ @15PG). The presence of PANI provides growth sites, resulting in a uniform and dense arrangement of NiS₂ . This morphological modulation of NiS₂ increases the contact area between the active material to electrolyte. Additionally, PANI effectively connects NiS₂ with the conductive network of GO, which advances the electrical conductivity and ion diffusion properties. As a result, the R_ct (charge transfer resistance) and Z_w (Warburg impedance) of NiS₂ @15PG decrease by 82.61 % and 66.76 % respectively. This unique structure confers NiS₂ @15PG with high specific capacitance (536.13 C g^-1 at 1 A g^-1 ) and excellent multiplicative property of 60.93 % at 20 A g^-1 . The assembled NiS₂ @15PG//YP-50 supercapacitors (HSC) demonstrates an energy density (13.09 Wh kg^-1 ) at a high-power density (16 kW kg^-1 ). The capacity retention after 10,000 cycles at 5 A g^-1 is 86.59 %, indicating its significant potential for practical applications.