Zeolitic imidazolate frameworks (ZIFs)-derived Ni_xCo_3−xO₄/CNTs nanocomposites with enhanced electrochemical performance for supercapacitor

Coupling Co-Ni bimetallic oxides with carbon nanotubes (CNTs) is recognized an effective strategy to enhance the performance of supercapacitors. In this work, porous Ni_xCo_3−xO₄/CNTs nanocomposites are prepared through in situ growth of ZIF-67 precursor onto CNTs followed by subsequent annealing. The obtained Ni_xCo_3−xO₄/CNTs combine the promising high storage performance of porous Ni_xCo_3−xO₄ with the excellent conductivity of CNTs. When test in three-electrode system, the electrode materials exhibit a high specific capacitance of 668 F/g at 1 A g⁻¹, a good rate capability of 91.60% retention from 1 to 10 A g⁻¹ and good cycling stability of 91.20% retention after 3500 cycles in 2.0 M KOH electrolyte. Furthermore, the Ni_xCo_3−xO₄/CNTs are tested in two-electrode configuration, showing a high energy density of 23.56 Wh kg⁻¹ at power density of 800.15 W kg⁻¹ and outstanding cycling stability of 93.75% retention after 3000 cycles. The excellent electrochemical performance of the designed nanomaterials can be ascribed to the synergy between the CNTs and Ni_xCo_3−xO₄.