Facile synthesis of heterogeneous Co3S4@Ni3S4 nanoflower arrays on Ni foam for high-performance asymmetric all-solid-state supercapacitors

Electrode materials with special microstructure and high surface area can accelerate ions/electrons diffusion and electrolyte permeability, thus improving the electrochemical properties of supercapacitors. The highly porous Co3S4@Ni3S4 heterogeneous nanoflower arrays (NFAs) supported on Ni foam were synthesized by a facile two-step hydrothermal reaction as the binder free electrode for supercapacitor. The obtained composite can provide efficient ions/electrons migration channels and excellent redox activities by integrating the advantages of Ni foam (outstanding electrical conductivity) and transition metal sulfide (high theoretical specific capacitance). Benefiting from the novel heterostructure and the synergistic effect of different components, the specific capacitances of Co3S4@Ni3S4 composite can reach 2817 and 1662 F g(-1) at the range of current density from 1 to 20 A g(-1) and the capacitance retention can remain 70% after 2000 cycles at 20 A g(-1). The assembled all-solid-state Co3S4@Ni3S4-2 h//AC asymmetric supercapacitor (ASC) device can offer the high energy density of 54.2 Wh kg(-1) at the power density of 799.7 W kg(-1) and maintain the energy density of 33.6 Wh kg(-1) even at the ultrahigh power density of 17.3 kW kg(-1). This work opens up an alternative design method for the synthesis of heterogeneous composite in the field of supercapacitors. (C) 2021 Elsevier B.V. All rights reserved.