Preparation of Porous Activated Carbons for High Performance Supercapacitors from Taixi Anthracite by Multi-Stage Activation

Coal-based porous materials for supercapacitors were successfully prepared using Taixi anthracite (TXA) by multi-stage activation. The characterization and electrochemical tests of activated carbons (ACs) prepared in different stages demonstrated that the AC from the third-stage activation (AC(III)) shows good porous structures and excellent electrochemical performances. AC(III) exhibited a fine specific capacitance of 199 F g(-1) at a current density of 1 A g(-1) in the three-electrode system, with 6 mol L-1 KOH as the electrolyte. The specific capacitance of AC(III) remained 190 F g(-1) even despite increasing the current density to 5 A g(-1), indicating a good rate of electrochemical performance. Moreover, its specific capacitance remained at 98.1% of the initial value after 5000 galvanostatic charge-discharge (GCD) cycle tests at a current density of 1 A g(-1), suggesting that the AC(III) has excellent cycle performance as electrode materials for supercapacitors. This study provides a promising approach for fabricating high performance electrode materials from high-rank coals, which could facilitate efficient and clean utilization of high-rank coals.