High performance asymmetric supercapacitor based on CoAl-LDH/GF and activated carbon from expanded graphite

Abstract

An asymmetric supercapacitor fabricated with CoAl-layered double hydroxide/graphene foam (LDH/GF) composite as the positive electrode and activated carbon derived from expanded graphite (AEG) as negative electrode in aqueous 6 M KOH electrolyte is reported. This CoAl-LDH/GF//AEG cell achieved a specific capacitance of 101.4 F g-1 at a current density of 0.5 A g-1 with a maximum energy density as high as 28 Wh kg-1 and a power density of 1420 W kg-1. Furthermore, the supercapacitor also exhibited an excellent cycling stability with ∼ 100% capacitance retention after 5000 charging-discharging cycles at a current density of 2 Ag-1. The results obtained show the potential use of the CoAl- LDH/GF//AEG material as suitable electrode for enhanced energy storage as supercapacitor.