Design and development of the high-performance aqueous asymmetric supercapacitor based on the hydrothermally grown binder-less Ni-Co LDH nanosheets

Because of the high energy demand, hybrid supercapacitors (HSC) are one of the best options in energy storage systems. The energy demand can be fulfilled by achieving superior energy density. Recently, layered double hydroxides (LDHs) have been favoured as magnificent supercapacitive electrode materials due to their capability of storing high energy density using their tuneable layered structure. In this study, we have synthesized nickel‑cobalt layered double hydroxide on nickel foam (Ni-Co LDH/NF) by utilizing a low-cost hydrothermal technique to obtain high energy density. To monitor the effect of the morphological aspects on electrochemical performance, reaction time during synthesis was varied. The structural and compositional studies confirmed Ni-Co LDH deposition on the Ni-foam. The morphological analysis showed highly interconnected nanosheets which efficiently provided fast transport pathways for electrons and electrolyte ions. The Ni-Co LDH/NF film synthesized at 6 h delivered a distinguished rate capability with a specific capacitance of 1577 F/g at 1 mA/cm2. Notably, a fabricated aqueous asymmetric supercapacitor showed a good energy density of 38 Wh/kg. These results highlighted the remarkable advantages of the binder-less nanosheet structure of the Ni-Co LDH for potential use in the supercapacitor application.