Multi-dimensional Ni(OH)2/(Ni(OH)2(NiOOH).167).857@Ni3S2 hierarchical structure for high-performance asymmetric supercapacitor

Abstract

Multi-phase composite with multi-dimensional nano-structure is proved to have a more optimized electronic structure and abundant reactive active sites, which can effectively enhance the electrochemical behavior of the material. Herein, a three-phase hierarchical nanostructure electrode, Ni(OH)2/(Ni(OH)2(NiOOH).167).857@Ni3S2 (Ni(O)OH@Ni3S2), composed of 3-dimension (3D) Ni3S2 particles coated on the surface of the interlaced 1-dimension (1D) nanowires and 2-dimension (2D) nanosheets Ni(O)OH array, is successfully designed and constructed by a facile one-pot hydrothermal strategy. The formation mechanism is discussed by exploring the effect of S element content and hydrothermal time on the products. Benefiting from the synergistic effect between multi-dimensional nanomaterials, the Ni(O)OH@Ni3S2-1.0 composite electrode can deliver a high areal capacitance (11.74F cm−2 at 2 mA cm−2), displaying remarkable electrochemical behavior. In addition, the assembled Ni(O)OH@Ni3S2//AC asymmetric supercapacitor exhibits an areal energy density of 0.632 mWh cm−2 and an excellent cycling stability performance of 86.4 % after 6000 cycles at 100 mA cm−2. This work proposes the possibility and effectiveness of a one-step method to fabricate multi-dimensional and multi-phase composites for high-performance energy storage devices.