MXene/Ni foam supported Co-doped Ni3S2 as a binder-free electrode for enhanced performance of supercapacitors

The reasonable design of electrode materials with high electrochemical activity and stable structure after long cycles can effectively improve the electrochemical performance of supercapacitors. In this paper, Co-doped Ni3S2 supported on Ti3C2/Ni foam (Co-Ni3S2/Ti3C2/NF) composites were prepared using a feasible hydrothermal method. The composite materials were characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that the Co-Ni3S2/Ti3C2/NF materials had a three-dimensional network structure. Electrochemical performance tests were conducted for the Co-Ni3S2/Ti3C2/NF electrode. The prepared Co-Ni3S2/Ti3C2/NF electrode has good electrochemical performance with specific capacitance of 1457 F g(-1) at 1 A g(-1). At 10 A g(-1), the specific capacity after 5000 cycles is 127.35% of the initial specific capacity. The asymmetric supercapacitor with Co-Ni3S2/Ti3C2/NF as the positive electrode and activated carbon (AC) as the negative electrode has an energy density of 30.4 Wh kg(-1) at power energy density of 0.8 kW kg(-1). This strategy provides a useful method for the design of supercapacitor electrodes with excellent electrochemical performance coated with MXenes.