Preparation of activated carbons for electrochemical capacitors by microwave heating
Activated carbons (ACs) were prepared from lignite by microwave heating with KOH as activation agent, the effects of the weight ratio of KOH to coal and microwave heating time on the pore structure of ACs were investigated by N2 adsorption. The electrochemical characteristics of Electrochemical capacitors(ECs) with ACs as electrodes in 3mol/L KOH electrolyte were evaluated by galvanostatic charge/discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the BET specific surface area and total pore volume of ACs (denoted as AC-R3) can reach 2097m 2 /g and 1.19cm 3 /g respectively when the weight ratio of KOH to coal is 3:1 and the microwave heating time is 10 min. The ECs with AC-R3 as electrodes presents a high specific capacitance of 335F/g at a low current density of 50mA/g and still remains 288F/g even at a high current density of 5A/g, it has excellent cycling stability and low leakage current, and the residual specific capacitance is as high as 93.6% after 1000 cycles under the current density of 2.5A/g. The results have demonstrated that the microwave heating with KOH activation is an efficient approach to prepare ACs with high performance for ECs.
Baolin Xing Lunjian Chen Chuanxiang Zhang Hui Guo Xiaojiao Wang
School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo,454003,China
国际会议
桂林
英文
1-9
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）