微波法制备电化学电容器用花生壳基活性炭

摘要

Activated carbons ( ACs) were prepared from peanut shells by KOH activation under microwave heating and were used as electrode materials for electrochemical capacitors ( ECs) . The pore structure of the ACs was characterized by nitrogen adsorption andthe electrochemical performance by galvanostatic charge_discharge and cyclic voltammetry. Results show that the ACs’ specific surface area, total pore volume, specific capacitance, as well as energy density are maximized using anactivation time from 6 to 10 min or KOH/peanut shell mass ratio from 0. 6 to 2. 0 under otherwise identical conditions. When the KOH/peanut shell mass ra_tio was 1. 0, microwave power was 600 W and activation time was 8 min, the specific surface area of the resulting AC was 1 277 m2/g and its energy density was 8. 38 Wh/kg after 1 000 cycles. The KOH activation of peanut shells with microwave heating is an efficient approach for the rapid preparation of low cost ACs for ECs.%以花生壳为原料,氢氧化钾为活化剂,采用微波加热制备出活性炭,所制活性炭用于制备电化学电容器用电极材料。通过氮气吸附、恒流充放电及循环伏安对所制活性炭的孔结构及电化学性能进行研究。结果表明,活性炭的比表面积、总孔容、比电容以及能量密度在炭化时间(6_10 min)以及KOH与花生壳的质量比(0.6_2.0)的范围内存在最大值。当KOH/花生壳的质量比为1.0,微波功率为600W,活化时间8min,所制活性炭(AC1_600_8)比表面积达1277m2/g,并且经1000次循环后,其能量密度高达8.38 Wh/kg。因此采用微波加热、KOH活化是一种快速制备电化学电容器用活性炭的低成本方法。