Synthesis of CNTs/CoNiFe-LDH Nanocomposite with High Specific Surface Area for Asymmetric Supercapacitor

Ternary layered double hydroxide (LDH) materials have shown promising application in hybrid supercapacitors. However, the low electrical conductivity of LDHs is still a restriction to their performance. Herein, carbon nanotubes/cobalt-nickel-iron LDH (CNTs/CoNiFe-LDH) hybrid material was prepared by a one-step hydrothermal approach for the first time. The presence of CNTs improved the conductivity and surface area of the electrode, leading to an enhanced electrochemical performance. The CNTs/CoNiFe-LDH hybrid electrode exhibited high specific capacity 170.6 mAh g^-1 at a current density of 1 A g^-1, with a capacity retention of 75% at 10 A g^-1. CNTs/CoNiFe-LDH//AC asymmetric supercapacitor (ASC) was also assembled, which had high specific capacitance (96.1 F g^-1 at the current density of 1 A g^-1), good cycling stability (85.0% after 3000 cycles at 15 A g^-1) and high energy density (29.9 W h kg^-1 at the power density of 750.5 W kg^-1). Therefore, the CNTs/CoNiFe-LDH material could be used for hybrid supercapacitor electrodes.