Nickel cobalt sulfide nanoparticles grown on titanium carbide MXenes for high-performance supercapacitor

The Ni1.5Co1.5S4@Ti3C2 hybrid materials with different MXene contents have been synthesized through in-situ growing Ni1.5Co1.5S4 nanoparticles on few-layer Ti3C2 nanoflakes using a simple one-step hydrothermal method. The supercapacitive performances of the hybrid materials are optimized by tuning the composition of the hybrid materials from the atomic ratios of nickel and cobalt to content of heterogeneous components. Owing to achieving the maximum of synergistic effects at multi-scales, the Ni1.5Co1.5S4@Ti3C2-5 electrode shows a high specific capacitance of 166.7 mAh g(-1) at the current density of 1 A g(-1), and superior rate capability with capacitance retention rate of 73.9% after a 20 time increase in current densities. Impressively, an asymmetric supercapacitor, assembled with Ni1.5Co1.5S4@Ti3C2-5 as positive electrode and activated carbon as negative electrode, delivers high energy density of 49.8 Wh kg(-1) at a power density of 800 W kg(-1), and an excellent cycling stability of 90% capacitance retention after 8000 cycles at 10 A g(-1), demonstrating a great prospect for practical applications in the fields of energy storage. (C) 2019 Elsevier Ltd. All rights reserved.