Ultrafast One-Step Method for Synthesis of Nanoflower-Like Composites of Metal Carbides and Coco Layered Double Hydroxides Towards Ultrahigh Supercapacitor Performance

Abstract

Layered double hydroxides (LDHs) have been paid significant attention as electrode materials for supercapacitors due to their excellent electrochemical performance and high theoretical specific capacity. Unfortunately, because of the poor conductivity of LDHs, the experimental capacity is much lower than the theoretical value. Similarly, 2D transition metal carbides (MXene) have received research attention for their utilization in energy storage electronic devices. However, due to self-restacking, the access of electrolyte ions to the active sites of material is hindered. Therefore, in this research work, an ultrafast one-step method for the synthesis of 3D nanoflower-like F-Mxene/CoCo LDH composites has been proposed. Composite materials synergistically combine the high theoretical capacity of LDH with good electrical conductivity of MXene, using 2-methylimidazole ligand and methanol solvent, resulting in outstanding electrochemical performance and excellent stability for supercapacitors. Due to the synergistic effect of MXene and LDHs, the resulting composite material exhibits the highest specific capacitance of 1061.2 F/g at a scan rate of 5 mV/s and a maximum energy density of 32.13 Wh/kg is obtained at a power density of 324.97 kW/kg. Furthermore, the capacitance retention rate is as high as 84.1% after 100,000 cycles at a current density of 1 A/g.

Keywords: supercapacitors, MXene, Layered Double hydroxides, Ultrafast synthesis