Core-shell Cu2O@CuS@NiCo layered double hydroxide composites as supercapacitor electrode materials

Abstract

A facile multi-step strategy was designed to synthesize core-shell Cu2O@CuS @NiCo-LDH (LDH, layered double hydroxide) composites. Initially, the Cu2O@CuS matrix material was synthesized by heat treatment and vulcanization at 25 °C, and subsequently, the desired Cu2O@CuS@NiCo-LDH composites were obtained using a hydrothermal method. A core-shell structure consisting of nanosheets uniformly grown on the cubic surface of the core–shell unit was achieved. The states and properties of nanosheet loading with different ratios of Ni and Co were investigated. and Cu2O@CuS @NiCo-LDH in supercapacitors, and a specific capacitance of 970.5 F g−1 was obtained at 1 A g−1. Density functional theory simulations provided additional confirmation of the beneficial synergistic interaction between Cu2O@CuS and NiCo-LDH. The constructed Cu2O@CuS@NiCo-LDH//activated carbon asymmetric supercapacitor (ASC) also attained an energy density of 53.3 Wh kg−1 at a power density of 820 W kh−1. Additionally, the assembled ASC demonstrated extremely high stability with a capacitance retention of 85.5 % after 25,000 cycles of testing thanks to its distinct structure design. These results indicate that the Cu2O@CuS@NiCo-LDH electrode shows promise for application as an energy-storage electrode material.