synthesis and characterization of layered double hydroxide bimetallic nanostructures and their application as supercapacitor

Abstract: supercapacitors as one of the electrical energy storage devices differ from conventional capacitors due to their fast charge–discharge rates, longer life cycle, high power, and high energy density [1]. recently several activities have been carried out to increase their efficiency in various fields, including more efficient electrode materials [2]. layered double hydroxides (ldhs) have received scientific attractions due to their unique two-dimensional (2d) structure, band gap tunability, and composition flexibility [3]. in this study, a hierarchical znco ldh@nis core–shell nanostructures with a battery-like nature were synthesized by the hydrothermal and electrodeposition methods for hybrid supercapacitors. in a three-electrode cell, the znco ldh@nis core–shell acquires excellent capacity (2448 f g-1, 297.2 mah g -1 at 2 a g-1), considerable rate performance and a good durability which is superior to the znco ldh and nis electrodes. moreover, the asymmetric supercapacitor (asc) which was fabricated with znco ldh@nis as a positive electrode and activated carbon as negative electrode demonstrated the maximum energy density of 38.016 wh kg-1, power density of 412 w kg-1 and desirable cyclability. the present synthesis provides a praiseworthy source for the fabrication of other kinds of metal ldh/sulfide electrode materials with core−shell structures for various applications.