Synergistic enhancement of supercapacitor performance: Modish designation of BPQD modified NiCo-LDH/NiCo2S4 hybrid nanotube arrays with improved conductivity and OH– adsorption

Hierarchical NiCo-LDH/NiCo2S4/BPQD nanotube arrays are developed to enhance the charge storage capacity of supercapacitor. [Display omitted] •Hierarchical NiCo-LDH/NiCo2S4/BPQD nanotube arrays are successfully prepared.•The unique heterostructure electrode obtains a high specific capacitance of 2938.2F g−1.•The tubular structure can expose sufficient redox reaction active sites and abundant ion-electron pathways.•The assembled supercapacitor exhibits an excellent energy density of 133.7 Wh kg−1. Constructing heterostructures with nanotube arrays not only provides rich ion electron pathways to promote rapid Faraday reactions, but also enhances interfacial electron transfer, supplying larger capacitance and rapid energy storage. Herein, NiCo-layered double hydroxide (LDH)/NiCo2S4 nanotube arrays decorated with black phosphorus quantum dots (BPQD) is prepared through solvothermal method and electrostatic adsorption. In the unique structure, tubular structure of NiCo-LDH/NiCo2S4/BPQD nanoarrays on carbon cloth can expose sufficient redox reaction active sites and multiple ion diffusion channels to promote rapid faradic reactions. Density functional theory (DFT) theoretical calculations further confirm the enhancement of conductivity and OH– adsorption in ternary composite materials. The as-obtained NiCo-LDH/NiCo2S4/BPQD achieves an ultra-high capacitance of 2938.2F g−1 at 1.0 A g−1. Finally, an asymmetric supercapacitor consists of activated carbon and NiCo-LDH/NiCo2S4/BPQD exhibits a satisfactory energy density of 133.7 Wh kg−1 at 800 W kg−1. In addition, after 10,000 repetitions of charging/discharging, the capacitance still remains 76.5 %. Above results suggest that NiCo-LDH/NiCo2S4/BPQD electrode may facilitate the further development of hierarchical array structure electrodes in the energy storage field.