Enhanced electrochemical performance of asymmetric supercapacitor device fabrication of Ni-BDC derived Ni(OH)2@Ni-BDC nanocomposite

Abstract

Nanocomposites of metal–organic frameworks (MOFs) with metal hydroxide provide an effective approach to improve the ability of energy storage. Solvothermally prepared sheet-like Ni-BDC integrated with agglomerated β-Ni(OH)₂ particles through a simple slow evaporation process in a water solvent system. The synthesized Ni-BDC@Ni(OH)₂ exhibited a remarkable specific capacitance of 4979 F/g, as determined from galvanostatic charge–discharge analysis at a current density of 4 A/g, surpassing both Ni(OH)₂ (507.96  C/g) and Ni-BDC (862.2 F/g) alone. The assembled Ni-BDC@Ni(OH)₂//AC asymmetric energy storage device delivered a maximum energy density of 50.9 Wh/kg at a power density of 1527.1 W/kg. It also demonstrated good cycling stability, retaining 91.1 % of its initial capacitance after 5000 charge–discharge cycles. Seven devices were connected in series, charged for 2 min, and used to power a toy fan for 5 s. Two of the devices were stored at room temperature for one week. These two devices still have the ability to power LEDs for approximately 7 min. These findings offer crucial insights for advancing novel electrode materials that can simultaneously achieve high energy density and high-power density in energy storage applications.