Preparation and Characterization of Activated Carbons from Oxygen-rich Lignite for Electric Double-layer Capacitor

Activated carbons (ACs) were derived from oxygen-rich lignite via chemical activation for electric double-layer capacitor (EDLC). The preparation parameters affect the pore structure and specific surface area of ACs were discussed in this work. The pores of the ACs are mainly micropores and the functional groups of ACs are not changed compared with SL. When the carbonized temperature is 700 oC, activated temperature is 800 oC and KOH/char ratio is 4, the AC is rich in C-O, C=O and -COOH species, exhibits excellent electrochemical performance with the maximum specific capacitance of 213 F g-1 in 6 M KOH at the current density of 40 mA g-1. Furthermore, the electrode exhibits excellent cycle stability. Therefore, the AC electrodes derived from lignite are promising candidates for EDLC.