电化学双电层电容器动态模拟：离子尺寸及扩散系数的优化  

Simulation and optimization of electrochemical double layer capacitors: effects of ion size and diffusion coefficient

作　　者：鲁浩天 陈怡沁 周静红[1] 隋志军[1] 周兴贵[1] LU Haotian;CHEN Yiqin;ZHOU Jinghong;SUI Zhijun;ZHOU Xinggui(State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化学工程联合国家重点实验室

出　　处：《化工学报》2019年第10期4021-4031,共11页CIESC Journal

基　　金：国家重点基础研究发展计划项目(2014CB239702);国家自然科学基金项目(21676082)

摘　　要：电化学双电层电容器的低能量密度限制了其在储能动力等领域的应用,而有机电解液作为提升器件能量密度的关键因素,研究其导电电解质的特性具有重要的意义。通过构建电化学双电层电容器的动态模型,模拟了电化学双电层电容器的循环伏安曲线,并定量探究和解析了离子溶剂化尺寸和扩散系数对电容性能的影响。模拟结果表明:在低扫描速率情况下,电容性能主要受控于双电层结构特性,比电容随着离子溶剂化尺寸的减小而增大,而离子扩散系数对其电容性能没有影响;在高扫描速率情况下,电容性能会受控于离子传质过程,比电容随着离子溶剂化尺寸和离子扩散系数的增大而增大。并基于模拟计算和分析结果提出了理性设计和优化电化学双电层电容器的策略。The low energy density of electrochemical double layer capacitors limits its application in the field of energy storage power.Organic electrolytes,as a key factor in improving the energy density of devices,are of great significance in studying the properties of conductive electrolytes.Ion size and diffusion coefficient in organic electrolyte are the critical factors in determining the energy density of electrochemical double layer capacitors.A dynamic model of electrochemical double layer capacitors was established to simultaneously account for transport process,Stern and diffuse layers and the saturation phenomenon of dielectric permittivity.The cyclic voltammetry measurement of electrochemical double layer capacitors was numerically simulated for different ionic solvation sizes and diffusion coefficients.The simulation results indicated that the specific capacitances were only affected by ionic solvation sizes at low scan rates,increasing significantly with decreasing ionic solvation size,whereas the ionic diffusion coefficients had no effect on the specific capacitances which were mainly controlled by the Stern layer at low scan rates.However,the specific capacitances,which were mainly controlled by the ionic transport within the diffuse layer at high scan rates,were simultaneously affected by ionic solvation sizes and diffusion coefficients.The specific capacitances increased considerably with increasing ionic solvation size or diffusion coefficient at high scan rates.Finally,the strategies for rational design of electrochemical double layer capacitors is proposed based on the simulation results.

关 键 词：电化学双电层电容器 动态建模 电解质 离子尺寸 扩散系数 优化设计 

分 类 号：TQ152[化学工程—电化学工业]