Nowadays, there is constant demand for the development of energy storage materials using advanced methodologies. In this scenario, a large-scale environmentally friendly synthesis was chosen to prepare Ni-Co-layered double hydroxide (LDH) composites for asymmetric supercapacitors. The developed materials had a flower-like porous architecture with very low dimensional layers and a large surface area. The developed Ni-Co/LDH composite electrodes showed impressive specific capacitance of 1095.1 F/g at a current density of 1 A/g and maintained 492.5 F/g even at a current density of 20 A/g. In particular, the Ni-Co/LDH composites maintained 86.9% of their initial capacitance even after 5000 cycles at a high current density of 2 A/g. Furthermore, an asymmetric supercapacitor with Ni-Co/LDH composites demonstrated an excellent energy density of 40.7 Wh/kg at a power density of 750 W/kg.