有机电解质的黏性系数对超级电容充电特性的影响  

Organic electrolytes viscosity effect for the charging properties of supercapacitor

作　　者：高海峡 GAO Hai-xia(College of Science,Hunan University of Science and Engineering,Yongzhou 425199,China)

机构地区：[1]湖南科技学院理学院,湖南永州425199

出　　处：《湘潭大学学报（自然科学版）》2021年第2期71-79,共9页Journal of Xiangtan University(Natural Science Edition)

基　　金：湖南省自然科学基金项目(2020JJ4322);湖南省教育厅科研项目(19A193);湖南科技学院引进人才项目(No.111021804013);湖南科技学院应用特色学科建设计划资助项目。

摘　　要：黏性系数是量度流体黏滞性大小的物理量,它是与流体传输现象相关的最重要的物理性质之一.在超级电容充电过程中,电解质黏性系数对充电性能存在一定的影响,目前大部分理论计算将其忽略,而Archer的动态密度泛函理论对其进行了很好的考虑.该文采用Archer的动态密度泛函理论,对超级电容两种常见有机电解质(四乙基六氟磷酸铵/碳酸丙烯酯和四氟硼酸锂/乙腈)的充电特性进行研究.通过模拟运算得到超级电容在充电过程中电极表面的电荷密度随时间的动态演化及电极附近的离子密度分布和电容内的静电势分布情况.并与含时密度泛函理论描述的结果进行对比,发现超级电容电解质黏性系数较小时,在充电过程中电极表面的电荷密度随时间存在弱阻尼振荡现象,从而证明有机电解质黏性系数对超级电容充电特性的影响.The viscosity coefficient is a physical quantity to measure the viscosity of the fluid,and it is one of the most important physical properties related to the fluid transport phenomenon.In the charging process of the supercapacitor,the electrolyte viscosity coefficient has a certain influence on the charging performance,which is ignored by most theoretical calculations at present,while Archer's dynamic density functional theory(DDFT)has taken it into good consideration.In this paper,the charging characteristics of two common organic electrolytes(tetraethylammonium hexafluorophosphate/propylene carbonate and lithium tetrafluoroborate/ethyl propyl)in supercapacitors were studied by using Archer's DDFT.Some numerical results of supercapacitor in the charging process were obtained through simulation operation,such as the dynamic evolution of the charge density on the electrode surface with time,the ion density distribution near the electrode,and the electrostatic potential distribution.Compared with the results described by the time-dependent density functional theory,it is found that when the viscosity coefficient of the electrolyte is small,the charge density on the surface of the electrode oscillates weakly with time during the charging process,which proves that the electrolyte viscosity coefficient influence the charging properties of the supercapacitor.

关 键 词：黏性系数 动态密度泛函理论 有机电解质 超级电容 

分 类 号：O645[理学—物理化学]