Abstract
Layered double hydroxide (LDH) has great potential as advanced electrode material for supercapacitor. In this paper, by tuning the reaction temperature, two Ni Co-LDH nanostructures (hollow nanocage and sea urchin) were synthesized through the hydrolysis etching process of ZIF-67 crystals and Ni~(2+) ions. It has been found that the morphology of the electrode material has a great influence on the electrochemical performance and analysis the reason of this behavior is essential for understanding the morphology-related electrochemical performance. Here, a much more capacitive charge storage behavior of hollow Ni Co-LDH than that of sea urchin-shaped product is demonstrated by electrochemical kinetic analysis. The higher capacitive behavior of hollow Ni Co-LDH suggests a rapid surface redox reaction during the electrochemical process, which will lead to excellent electrochemical properties. An asymmetric supercapacitor assembled using hollow NiCo-LDH as the positive electrode displays a high energy density of 88.6 Wh kg~(-1) at 749.9 W kg~(-1), further demonstrating its great application potential. These results provide insights into the reasons for the excellent electrochemical performance of hollow nanostructure.
NSTL
Elsevier