In-situ growth of hierarchical NiCo2S4/MoS2 nanotube arrays with excellent electrochemical performance

NiCo2S4/MoS2 Nanocomposites for Long-Life High-Performance Hybrid Supercapacitors

Metal sulfides (MS) and mixed metal sulfides (MTMS) have been considered potential candidates over their metal oxide/mixed metal oxide counterparts in recent years. Herein, one MTMS, i.e., NiCo₂S₄, was combined with 2D MS MoS₂ through a single-step solvothermal process with different morphologies (sheet-like and rod-like) for supercapacitor applications. The resulting electrode exhibited excellent coulombic efficiency, high specific capacitance, superior energy density, and, most importantly, ultra-high cycling stability. In particular, the electrode delivered a capacitance of 2594 F g^-1 at 0.8 A g^-1 after 45,000 charge/discharge cycles with a remarkable stability of 192%. Moreover, the corresponding hybrid supercapacitor device displayed an impressive coulombic efficiency of 123% after 20,000 cycles and 118% after 45,000 cycles. In addition, the device also exhibited a decent energy density of 31.9 Wh kg^-1 and good cycling stability of 102% over 15,000 cycles.

Improved chemical precipitation prepared rapidly NiCo2S4 with high specific capacitance for supercapacitors

In this work, rapid chemical precipitation assisted annealing method is used to prepare flower-like NiCo₂S₄. And the flower-like structure after polyethylene glycol (PEG) modification yields an excellent specific capacitance (2198.9 F g^-1 at 1 A g^-1). And an asymmetric supercapacitor assembled with NiCo₂S₄ (PEG-modified) and activated carbon (AC) shows an energy density of 38.2 Wh kg^-1 at 400 W kg^-1, and outstanding stability (80% remained after 3000 cycles at 5 A g^-1). Benefited by a larger specific surface area and suitable pore size of the aggregate structure, the specific capacitance of prepared NiCo₂S₄ is increased by about 2 times. This uncomplicated preparation method is proved to be suitable for NiCo₂S₄ with a high specific capacitance of supercapacitors.

Hollow core–shell NiCo2S4@MoS2 dodecahedrons with enhanced performance for supercapacitors and hydrogen evolution reaction

Hollow core–shell NiCo₂S₄@MoS₂ heterostructures were fabricated using zeolitic imidazolate frameworks as templates and exhibited enhanced electrochemical performance for supercapacitors and hydrogen evolution reaction.