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Supercapacitors (SCs) are attractive as promising energy storage devices because of their distinctive attributes, such as high power density, good current charge/discharge ability, excellent cyclic stability, reasonable safety, and low cost. Electrode materials play key roles in achieving excellent performance of these SCs. Among them, binary transition metal sulfides (BTMSs) have received significant attention, attributed to their high conductivity, abundant active sites, and excellent electrochemical properties. This topic review aims to summarize recent advances in principles, design, and evaluation of the electrochemical performance for nanostructured BTMSs (including nickel–cobalt sulfides, zinc–cobalt sulfides, and copper–cobalt sulfides.) and their nanocomposites (including those carbon nanomaterials, transition metal oxides, binary transition metal oxides, transition metal sulfides, and polymers). Nanostructuring of these BTMSs and nanocomposites as well as their effects on the performance were discussed, including nanoparticles, nanospheres, nanosheets, nanowires, nanorods, nanotubes, nanoarrays, and hierarchitectured nanostructures. Their electrochemical performance has further been reviewed including specific capacitance, conductivity, rate capability, and cycling stability. In addition, the performance of hybrid supercapacitors (HSCs) assembled using the nanostructured BTMSs as the cathodes also have been summarized and compared. Finally, challenges and further prospects in the HSCs-based BTMS electrodes are presented. [ABSTRACT FROM AUTHOR]

• Flower-like Zn doped Ni(OH) 2 @CNTs (ZNC) was in-situ synthesized by a colloidal method at room temperature. • ZNC shows a high specific capacity of 726.5 C g-1 at 1 A g-1 and maintains 72.9% at 10 A g-1. • The energy density of ZNC//AC hybrid supercapacitor (HSC) is 51.3 Wh kg-1 at the power density of 409.6 W kg-1. • After 50,000 cycles, the energy density of ZNC//AC HSC maintains 29.33 Wh kg-1 at 16.5 kW kg-1. • After 50,000 cycles, the capacity of the HSC becomes 115.8% of its initial value. Transition metal oxides and hydroxides are typically applied as electrode materials for supercapacitors, but it is often difficult to achieve both their high power density and energy density simultaneously. Herein, electrodes of flower-like Zn doped Ni(OH) 2 combined with carbon nanotubes (i.e., Zn doped Ni(OH) 2 @CNTs) were in-situ synthesized using a colloidal synthesis method at room-temperature, assisted by cetyltrimethyl ammonium bromide (CTAB) and NaBH 4. This electrode exhibits an excellent electrochemical performance, achieving a high specific capacity of 750.5 C g-1 at 0.5 A g-1 and maintaining 72.9% of its initial value when the current density is increased from 1 A g-1 to 10 A g-1. A hybrid supercapacitor (HSC) assembled using the Zn doped Ni(OH) 2 @CNTs as the positive electrode and an active carbon as the negative electrode exhibits a capacity of 201.7 C g−1 at 1 A g-1 and an energy density of 51.3 Wh kg-1 at a power density of 409.6 W kg-1. After running for 50,000 cycles at a current density of 6 A g-1, the capacity of the HSC becomes 115.8% of its initial value. Moreover, this HSC maintains a high energy density of 29.33 Wh kg-1 at a high power density of 16.5 kW kg-1 after cycling for 50,000 times, which indicates its suitability for energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]