Characterization of Co-Mn layered double hydroxide nanostructures covered on Co3O4 as electrode material for supercapacitor applications

Abstract

In the present work, hybrids of porous Co3O4 nanostructures coated Co-Mn layered double hydroxide nanostructures array on Ni foam (Co3O4/Co-Mn LDH/NF) were designed and prepared via the hydrothermal reactions and calcination processes. The Co3O4 nanostructures can be utilized as the backbone to grow the Co-Mn layered double hydroxide (Co-Mn LDH) nanostructures. The effects of precursors on the morphology of the as-prepared electrodes were investigated by x-ray diffraction, energy dispersive x-ray analysis, field-emission scanning electron microscopy, and transmission electron microscopy. The electrochemical performance of the prepared Co3O4/Co-Mn LDH/NF electrode, compared with Co3O4/NF electrode, illustrated a high gravimetric specific capacitance 1462 F g−1 at current density 2 A g−1, excellent rate capability 71% at 22 A g−1, and excellent cycling stability of 83% capacitance retention after 3000 GCD cycles. Additionally, an asymmetric supercapacitor (Co3O4/Co-Mn LDH/NF//AC) based on the Co3O4/Co-Mn LDH/NF as a positive electrode and activated carbon (AC) as a negative electrode was successfully fabricated with excellent electrochemical performance. The asymmetric supercapacitor with a maximum voltage of 1.6 V has demonstrated a high energy density of 60.37 Wh kg−1 and a high power density of 800 W kg−1. Additionally, a LED can be lit up approximately for 6 min when two ASCs were connected in series. Therefore, this Co3O4/Co-Mn LDH/NF with outstanding electrochemical performance should envision potential practical applications in high-energy storage appliances.