Constructing an efficient conductive network with carbon-based additives in metal hydroxide electrode for high-performance hybrid supercapacitor.

• The CNTs/CNHs binary conductive additives design strategy is proposed. • The CNTs/CNHs modified LDH electrode exhibits superior electrochemical performance. • The synergistic mechanism between CNTs/CNHs and LDH are revealed. • The LDH@CNTs/CNHs//Activated carbon hybrid supercapacitor are assembled. Progress toward the development of advanced supercapacitor technologies is closely associated with high-performance electrode materials. Carbon-based conductive additives modifying electrode material effectively improves the electronic conductivity and promotes the redox reaction. In this paper, we developed a highly effective binary conductive additive to modify cobalt aluminum layered double hydroxide (CoAl LDH) electrode with superior electrochemical performance, where the binary carbon species included carbon nanotubes (CNTs) and carbon nanohorns (CNHs). The as-constructed binary conductive additives CNTs/CNHs present a highly efficient electronic transmission network via a "line to the surface to point" mode. The as-prepared CoAl LDH@CNTs/CNHs electrode exhibits a significantly enhanced specific capacitance, superior rate capability, and stable cycle life. Based on analyzing and studying the characterizations and simulation, we reveal the electron transport mechanism and synergistic effects between CNTs/CNHs and CoAl LDH in a new perspective. The assembled hybrid supercapacitor device exhibits a high energy density (62.2 Wh/kg) and good cycling ability (79% retention after 5500 cycles). We believe that the binary conductive additives design strategy presented here is expected to apply to other energy storage such as batteries and pseudocapacitors. [Display omitted] [ABSTRACT FROM AUTHOR]