The direct growth of Mn0.6Ni0.4CO3 nanosheet assemblies on Ni foam for high-performance supercapacitor electrodes

Abstract

Using Ni foam as a template, Mn_0.6Ni_0.4CO₃ nanosheet assemblies were synthesized by a hydrothermal method and calcination treatment. X-Ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray energy spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to determine the composition and the morphology of the sample. The electrochemical performance of the Mn_0.6Ni_0.4CO₃ nanosheet assemblies was investigated. The results show that the area-specific capacity of the electrode material in a 2 mol L⁻¹ KOH solution can reach 1.813 F cm⁻² at a current density of 10 mA cm⁻². The mass-specific capacity can reach 906.5 F g⁻¹, and the capacity only decreases by 3.4% after 2000 cycles, indicating that the material has excellent capacity performance. In addition, an asymmetric supercapacitor (ASC) was also assembled by using the Mn_0.6Ni_0.4CO₃ nanosheet assemblies and carbon as a cathode and anode, respectively, which delivered an energy density of 23.7 W h kg⁻¹ at the power density of 269.7 W kg⁻¹. The Mn_0.6Ni_0.4CO₃ nanosheet assemblies can be seen as a promising electrode material in the field of supercapacitors.