Synthesis and Printing Features of a Hierarchical Nanocomposite Based on Nickel–Cobalt LDH and Carbonate Hydroxide Hydrate as a Supercapacitor Electrode

Abstract

The hydrothermal synthesis of a hierarchically organized nanocomposite based on nickel–cobalt carbonate hydroxide hydrate of composition M(CO3)0.5(OH)·0.11H2O (where M is Ni2+ and Co2+) and nickel–cobalt layered double hydroxides (NiCo-LDH) was studied. Using synchronous thermal analysis (TGA/DSC), it was determined that the material retained thermal stability up to 200 °C. The crystal structure of the powder and the set of functional groups in its composition were determined by X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). The resulting hierarchically organized nanopowder was employed as a functional ink component for microplotter printing of an electrode film, which is an array of miniature planar structures with a diameter of about 140 μm, on the surface of a nickel-plated steel substrate. Using scanning electron microscopy (SEM), it was established that the main area of the electrode “pixels” represents a thin film of individual nanorods with periodic inclusions of larger hierarchically organized spherical formations. According to atomic force microscopy (AFM) data, the mean square roughness of the material surface was 28 nm. The electrochemical properties of the printed composite film were examined; in particular, the areal specific capacitance at different current densities was calculated, and the electrochemical kinetics of the material was studied by impedance spectroscopy. It was found that the electrode material under study exhibited relatively low Rs and Rct resistance, which indicates active ion transfer at the electrode/electrolyte interface.

Keywords

• carbonate hydroxide hydrate
• layered double hydroxides
• NiCo-LDH
• nanocomposite
• hydrothermal synthesis
• hierarchical structure