Synthesis of 2D Zn–Co LDH nanosheets by a successive ionic layer deposition method as a material for electrodes of high-performance alkaline battery–supercapacitor hybrid devices

In recent years, increasing attention directed at creating novel two-dimensional graphene-like materials, in particular materials based on oxides or hydroxides of transition metals, as they have a number of unique properties, which determine the perspective of their application in various fields of electronics and electrical engineering, as well as in energy storage devices. In this paper we propose a novel promising route for the synthesis of nanolayer layered double hydroxides on the basis of zinc and cobalt by a successive ionic layer deposition method. The obtained nanolayers were characterized by SEM, EDX, XRD, HRTEM, XPS and FT-IR. The results show the synthesized nanolayers were formed from two-dimensional nanocrystals with the thickness of about 6–9 nm and the morphology of the so-called “nanosheets” with the hydrotalcite-like crystal structure of an LDH. In addition, the obtained nanolayers were investigated as electrode materials for alkaline battery–supercapacitor hybrid devices and demonstrated a high specific capacitance (270 mA h g(−1) at 1 A g(−1)) and excellent electrochemical stability (3% drop in capacity after 1000 charge–discharge cycles).