Activated Carbon Prepared from Lignite as Supercapacitor Electrode Materials

Activated carbon derived from lignite is investigated as the active electrode material in supercapacitors. ZnCl2 was used as excitation agent during preparation process. XRD, BET, SEM and electrochemical performance testing carried out to characterize the structure and properties of activated carbon. Electrochemical investigations indicate that the activated carbon (AC-650°) shows the maximum specific capacitance of 207.5 F g−1 in 6 M KOH electrolytes at 0.5 A g−1. The activated carbon presents good cycle stability during 3,000 cycles at a fair current density of 5 A g−1 and capacity rate can reach 91 %, because of its specific surface area of 1024 m2 g−1.