有机电解液对双电层电容器性能影响  

Effect of Organic Electrolytes on Properties of Electrochemical Double-Layer Capacitor

作　　者：成果[1] 孙刚伟[1] 宋文华[1] 詹亮[1] 凌立成[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237

出　　处：《华东理工大学学报（自然科学版）》2010年第2期222-227,共6页Journal of East China University of Science and Technology

基　　金：国家自然科学基金重点项目(50720003)

摘　　要：采用石油焦基高比表面积活性炭作为电极材料,分别以1 mol/L Et4NBF4/PC(四乙基铵四氟硼酸盐/碳酸丙烯酯),Et4NBF4/AN(四乙基铵四氟硼酸盐/乙腈),Bu4NBF4/PC(四丁基铵四氟硼酸盐/碳酸丙烯酯)和Bu4NBF4/AN(四丁基铵四氟硼酸盐/乙腈)作为电解液,组装成有机体系双电层电容器。采用恒流充放电、循环伏安及交流阻抗等电化学手段对各电解液体系下的电化学行为进行了对比。实验结果表明:对于高微孔比率的电极材料,由于Et4N+(四乙基铵离子)的溶剂化离子半径小于Bu4N+(四丁基铵离子)的溶剂化离子半径,因此,Et4NBF4体系下的电荷存储密度和有效表面利用率更高,电容性能优于Bu4NBF4。此外,虽然PC体系的比容量略高于AN体系,但由于PC的电导率低于AN,致使其功率特性不如AN体系下的好。AN体系相比于PC体系具有更小的电荷传递阻抗和扩散阻抗,电容的频率响应性能要优于PC体系,更适宜在大功率场合下应用。Double-layer capacitors were prepared by using activated carbon（1 939.4 m^2/g） derived from petroleum coke as electrode and using 1 mol/L Et_4NBF_4/PC,Et_4NBF_4/AN,Bu_4NBF_4/PC and Bu_4NBF_4/AN as electrolytes,respectively.Their electrochemical performances were carried out through galvanostatic charge-discharge,cyclic voltammograms,and impedance spectroscopy measurements.The highest specific capacitance was obtained in Et_4NBF_4/PC system at low current loading.For Et_4NBF_4/AN,the least ionic transfer and diffusion resistance led to an excellent capacitance retention property.For Bu_4NBF_4,due to the larger solvated ion diameter and higher ion transfer resistance,the capacitive performances were inferior to those of Et_4NBF_4 in terms of specific capacitance and power density.In addition,owing to an excellent electric conductivity of AN,Et_4NBF_4/AN exhibited the best frequency response performance with the descant sequence of knee frequency Et_4NBF_4/ANBu_4NBF_4/ANEt_4NBF_4/PCBu_4NBF_4/PC.Compared with Et_4NBF_4/PC system,Et_4NBF_4/AN is more suitable as electrolytes in high power output.

关 键 词：超级电容 双电层 有机电解液 阻抗 

分 类 号：TQ424.25[化学工程]