Hydrothermal synthesis of layered NiS2/Ti3C2Tx composite electrode for supercapacitors

MXene shows potential to be used as electrodes in energy storage devices due to its unusual layered structure. MXene-based electrodes can store high rate faradaic pseudocapacitive energy because of their high surface area, metallic conductivity, thermal/chemical stability, and quick surface redox reactions. We present a hierarchy of NiS2/MXene nanohybrids made using a simple and low cost hydrothermal method. The strong interfacial connection and good electronic coupling between the NiS2 nanocube and MXene nanoplates improve structural stability and electrical conductivity as well as the electrolyte ion diffusion kinetics. Therefore, the obtained battery-type NiS2/MXene composite electrodes delivered 72.0 mAh g−1 at a current density of 1 A g−1 with high cycle stability in 1 M KOH electrolyte, and the fabricated asymmetric supercapacitor (ACS) demonstrates energy densities of 15.4 Wh kg−1 at power density of 351.6 W kg−1. It elucidates the mechanism and strategy for the development of MXene-based nanohybrid materials for electrochemical energy storage devices.