Zeolitic imidazolate frameworks (ZIFs)-derived NixCo3-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 NixCo3-xO4/CNTs nanocomposites are prepared through in situ growth of ZIF-67 precursor onto CNTs followed by subsequent annealing. The obtained NixCo3-xO4/CNTs combine the promising high storage performance of porous NixCo3-xO4 with the excellent conductivity of CNTs. When test in three -electrode system, the electrode materials exhibit a high specific capacitance of 668 Fig 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 NixCo3-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 NixCo3-xO4. (C) 2018 Elsevier Inc. All rights reserved.