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电化学(中英文) ›› 2021, Vol. 27 ›› Issue (5): 467-497.  doi: 10.13208/j.electrochem.201126

所属专题: “表界面”专题文章

• 教程 • 上一篇    下一篇

宏观均相多孔电极电化学阻抗谱基础

李响1, 黄秋安1,2,*(), 李伟恒2, 白玉轩1,2, 王佳1,2, 刘杨2, 赵玉峰2, 王娟1,*(), 张久俊2,*()   

  1. 1.西安建筑科技大学,陕西省纳米材料与技术重点实验室,陕西 西安 710055
    2.上海大学可持续能源研究院,上海 200444
  • 收稿日期:2020-11-26 修回日期:2020-12-25 出版日期:2021-10-28 发布日期:2021-02-09
  • 通讯作者: 黄秋安,王娟,张久俊 E-mail:hqahqahqa@163.com;juanwang168@gmail.com;jiujun.zhang@i.shu.edu.cn
  • 基金资助:
    国家自然科学基金项目(22078190)

Fundamentals of Electrochemical Impedance Spectroscopy for Macrohomogeneous Porous Electrodes

Xiang Li1, Qiu-An Huang1,2,*(), Wei-Heng Li2, Yu-Xuan Bai1,2, Jia Wang1,2, Yang Liu2, Yu-Feng Zhao2, Juan Wang1,*(), Jiu-Jun Zhang2,*()   

  1. 1. Shanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi,China
    2. Institute for Sustainable Energy, Shanghai University, Shanghai 200444, China
  • Received:2020-11-26 Revised:2020-12-25 Published:2021-10-28 Online:2021-02-09
  • Contact: Qiu-An Huang,Juan Wang,Jiu-Jun Zhang E-mail:hqahqahqa@163.com;juanwang168@gmail.com;jiujun.zhang@i.shu.edu.cn

摘要:

电化学阻抗谱可用于诊断多孔电极内电荷转移反应,即界面电荷集聚和电荷传导,以及反应物质输运。本文采用复相量方法,在同态假设条件下,重新推演多孔电极阻抗谱模型,厘清传统多孔电极阻抗谱模型中的模糊性表述。(1) 定义多孔电极表征输入参数,包括电极基体电子电导率σ1 、电解质离子电导率σ2、界面电荷传递电导率gct、单位面积界面电容C、固相扩散系数D、速度常数k、电极厚度d、特征孔深Lp 和单位体积表面积Sc;(2) 解析阻抗谱特征输出参数,包括场扩散常数K,特征频率ω0ω1ω2ω3ωmax,它们分别相关于界面传导反应、有限场扩散、氧化还原反应、孔内扩散和最小特征孔尺寸,以及分别对应于从传导到扩散和从扩散到饱和的转折频率fk1fk2;(3) 当参数XZ同时变化时(X = σ1Z = d,Sc,Lp,C,gct,D,k),通过阻抗谱特征参数的演变规律,分析了电荷转移反应中XΖ参数耦合竞争;(4)为深入分析电荷转移反应中参数XZ的耦合竞争,引入了分叉频率fXZfZXfXZfZX所处位置可以用于表征参数XZ影响电荷转移反应的深度和广度。当分叉频率fXZfZX不存在时,表明电荷转移反应中参数XZ在全频率范围内存在耦合竞争。总之,借助于特征频率和分叉频率,本文一方面研究了动力学参数和微观结构参数对多孔电极中电荷转移反应的影响,另一方面分析谱图的变化及其背后的阻抗谱特征演化规律。本文研究结果可为阻抗谱的系统仿真和辨识提供理论基础,可为多孔电极内电荷转移反应的竞争分析提供技术支撑,还可为电化学储能系统的优化设计提供诊断工具。

关键词: 多孔电极, 电荷转移反应, 电化学阻抗谱, 特征频率, 分叉频率

Abstract:

Electrochemical impedance spectroscopy (EIS) can be used to diagnose charge transfer reactions and mass transport in porous electrodes. The charge transfer reactions include interfacial charge accumulation and charge conduction as well as electrochemical reaction. In this paper, the complex phasor method is developed under the macrohomogeneous assumption to build an impedance model of porous electrodes for clarifying several vague expressions in the traditional approaches. The following researches are carried out: (1) Identifying characteristic parameters for the porous electrodes, including electrode electronic conductivity σ1, electrolyte ionic conductivity σ2, interface charge transfer conductivity gct, unit area interface capacitance C, solid phase diffusion coefficient D, rate constant k, electrode thickness d, characteristic hole depth Lp and unit volume surface area Sc ; (2) elucidating characteristic output parameters for the impedance spectroscopic response, including field diffusion constant K, characteristic frequencies ω0, ω1, ω2, ω3, and ωmax for interface conduction reaction, finite field diffusion, redox reaction, pore diffusion and minimum characteristic pore size, respectively. In addition, the transition frequencies fk1 and fk2 from conduction to diffusion area and from diffusion to saturation area are also defined and studied respectively; (3) defining the parameters X and Z, herein, X = σ1,Z = dSc, Lp , C, gct , D, k,which are responsible for the evolution trend of the characteristic parameters for impedance spectroscopic response, the competition effects of X and Z parameters coupled in charge transfer reaction are analyzed; (4) Further analyzing the competition effects of X and Z parameters coupled in the charge transfer reaction, the diverging frequencies fXZ and fXZ are phenomenologically defined. The locations of fXZ and fXZ can indicate the depth and breadth of the charge transfer reaction affected by the parameters X and Z. The non-existence of fXZ and fXZ indicates that the parameter X or Z can affect the charge transfer reaction over the whole frequency range. With the help of characteristic frequency and diverging frequency, the effects of electrode kinetic and microstructure parameters on the charge transfer reaction in porous electrodes are studied; on the other hand, the shape change and trend evolution of the impedance responses for porous electrodes are analyzed. The research results in this paper should be able to provide theoretical basis for system simulation and system identification of impedance spectroscopy, technical support for competitive analysis of charge transfer reaction in porous electrodes, and diagnostic tool for optimal design of electrochemical energy storage system.

Key words: porous electrode, charge transfer reaction, electrochemical impedance spectroscopy, characteristic frequencies, diverging frequencies