Preparation of Porous CoAl-layered Double Hydroxide/Graphene Composite with Enhanced Capacitive Performance for Supercapacitors

Abstract

In this study, a porous CoAl-layered double hydroxide/graphene (G-LDH) composite was fabricated onto an ammonia/ethylene glycol interface using a simple gas-liquid interfacial method. The porous G-LDH composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The obtained composite achieved a specific capacitance of 479.2 F g-1 and 341.2 F g-1 at a current density of 1 A g-1 and 10 A g-1, respectively. The obtained specific capacitance values were much higher than those of the pure LDH sample fabricated by the gas-liquid interfacial method and the LDH/graphene sample synthesized by the conventional hydrothermal method. In addition, the prepared sample has a specific surface area of 98.2 m2 g-1 and a pore volume of 0.42 cm3 g-1, which indicated that the gas-liquid interfacial method can control the precipitation of CoAl-LDH on GNS, leading to the porous of the G-LDH composite. Moreover, the G-LDH composite exhibited long and excellent cycle stability with 93.9% of the specific capacitance retained at 3 A g-1 after the 2000th cycle. This study introduces a promising approach to fabricate porous layered double hydroxide/graphene composite with high specific capacitance, large specific surface area, long cycle life and excellent cycle stability.