活性炭电化学性能与液相吸附性能间的关系

Relationship between Adsorption Capability in Aqueous Phase and Electrochemical Performances of Activated Carbons

表征了以典型商品活性炭及几种自制掺锰活性炭为原料制备的双电层电容器电极的循环伏安及定电流充放电特性,测定了活性炭对KOH水溶液中钾离子的吸附等温线,并根据拟合的Temkin方程计算了在KOH水溶液(w=30%)中活性炭对钾离子的平衡吸附量,在此基础上关联了活性炭对电解质的平衡吸附量与电化学性能之间的关系。结果表明:活性炭电极的比电容量随其对电解质平衡吸附量的增大而增大,平衡吸附量与比电容量成较好的线性关系,线性相关系数为0.970 5。

The electrodes of electric double layer capacitors （EDLCs） were assembled with typical commercial activated carbons, as well as various Mn-doped activated carbons prepared on lab scale. The electrochemical performances of these electrodes were characterized by cyclic voltammetry and charge discharge at constant current. Meanwhile, the adsorption isotherms of potassium ion from KOH aqueous solution onto activated carbons were determined. The experimental equilibrium adsorption data were fitted by Temkin equation, and the adsorption capacities of potassium ion onto activated carbons in KOH aqueous solution （w=30%） were determined. Finally, the relationship between adsorption capacities and specific capacitances of activated carbons was investigated. The results show that the specific capacitances of activated carbon electrodes increase with the increase of adsorption capabilities of electrolyte onto activated carbons. Moreover, there exists a definitive linear relationship between electrochemical performances of activated carbon electrodes and electrolyte adsorption capacities of activated carbons with a linear correlation coefficient of 0. 970 5.