Coal Based Activated Carbon Prepared by Microwave Heating and Its Electrochemical Performance

Activated carbon for supercapacitor was prepared from Inner Mongolia lignite by microwave heating with KOH as activation agent.The pore structures of activated carbon was characterized by N2 adsorption at 77K,the electrochemical performances of activated carbon electrode materials were evaluated by constant current charge-discharge and cyclic voltammetry,and compared with the Japanese commercial activated carbon for supercapacitor in structure and performance.The results show that high quality activated carbon can be prepared under the condition of the ratio of KOH to lignite was 3 and microwave activation time was 20min,which specific surface area was 2593m2/g,total pore volume was 1.685cm3/g,the ratio of mesopore was 67.3%,the pore size mainly distributed in 0.5-10nm,and average pore width was 2.61nm.In 3mol/L KOH electrolyte,the supercapacitor with the activated carbon as electrodes exhibited excellent electrochemical performances,its specific capacitance decreased from 346F/g to 273F/g as the current density increased from 50mA/g to 10A/g,indicating excellent power performance,and the residual specific capacitance was beyond 93.2% after 1000cycles.Compared with commercial activated carbon,the performance of activated carbon prepared by microwave heating was more excellent.