A facile method for synthesizing NiS nanoflower grown on MXene (Ti₃C₂T_x) as positive electrodes for “supercapattery”

Transition metal sulfide is a good choice for supercapacitor anode materials. Herein, 3D NiS with flower-like shape was grown on MXene (Ti₃C₂T_X) with one-step hydrothermal method. Connected nanoflakes in the composite formed a large void network structure, which favors the transfer of ions and charges. Compared with pure MXene, MXene/NiS composite exhibited higher specific capacity of 554.1 mAhg⁻¹ (857.8 F g⁻¹) at 1 A g⁻¹ which is approximately 4 times greater than that MXene and superior cycle performance of 99.49% capacitance retained after 3000 cycles at 5 A g⁻¹. The asymmetric supercapacitors were assemble in 2 M KOH alkaline solution with anode of MXene/NiS and cathode of G/AC (graphene/activated carbon). The ASCs device emerges a remarkable cycle performance of 97.7% after 3000 cycles and the energy density is up to 17.688 Wh kg⁻¹ at a power density of 750 W kg⁻¹. The small bulb (12 V, 2 W) can be lit for more than 100 s.