In-situ growth of NiS-Ni3S4 on dual-ligand Co-MOF as a new electrode for high-performance supercapacitors

Nowadays, new electrode materials for energy storage devices like mixed ligands and bi-metal MOFs have attracted a lot of attention owing to their high porosity and high capacity for charge storage. In this study, a Co-based metal-organic framework (4,4'-bpy = 4,4'-Bipyridine and H₃BTC = 1,3,5-Benzenetricarboxylic acid) was successfully fabricated by a hydrothermal method. To obtain good electrochemical behavior, Co-MOFs were modified using a porous spherical scaffold of NiS/Ni₃S₄ nanoparticles. The electrochemical efficiency was analyzed by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge methods. Detailed electrochemical scrutiny performed by Co-MOF/NiS-Ni₃S₄ in a 6 M KOH electrolyte reveals a high specific capacity of 136.67 mAh/g at 1 A/g, with a superb cycle life of 91%. Co-MOF/NiS-Ni₃S₄//AC asymmetric supercapacitor produces a large amount of energy density (33.32 Wh/kg) and power density (600 W/kg). The produced composite is an appropriate candidate for electrodes in both batteries and hybrid supercapacitors, owing to its favorable electrochemical characteristics.