Fundamentals of Electrochemical Impedance Spectroscopy for Macrohomogeneous Porous Electrodes

Authors

Xiang Li, 1. Shanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi,China;
Qiu-An Huang, 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;Follow
Wei-Heng Li, 2. Institute for Sustainable Energy, Shanghai University, Shanghai 200444, China;
Yu-Xuan Bai, 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;
Jia Wang, 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;
Yang Liu, 2. Institute for Sustainable Energy, Shanghai University, Shanghai 200444, China;
Yu-Feng Zhao, 2. Institute for Sustainable Energy, Shanghai University, Shanghai 200444, China;
Juan Wang, 1. Shanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi,China;Follow
Jiu-Jun Zhang, 2. Institute for Sustainable Energy, Shanghai University, Shanghai 200444, China;Follow

Corresponding Author

Qiu-An Huang(qiuan_huang@shu.edu.cn);
Juan Wang(juanwang168@gmail.com);
Jiu-Jun Zhang(jiujun.zhang@i.shu.edu.cn)

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 g_ct, unit area interface capacitance C, solid phase diffusion coefficient D, rate constant k, electrode thickness d, characteristic hole depth L_p and unit volume surface area S_c ; (2) elucidating characteristic output parameters for the impedance spectroscopic response, including field diffusion constant K, characteristic frequencies ω₀, ω₁, ω₂, ω₃, and ω_max for interface conduction reaction, finite field diffusion, redox reaction, pore diffusion and minimum characteristic pore size, respectively. In addition, the transition frequencies f_k1 and f_k2 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 = d、S_c, L_p , C, g_ct , 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 f_XZ and f_XZ are phenomenologically defined. The locations of f_XZ and f_XZ can indicate the depth and breadth of the charge transfer reaction affected by the parameters X and Z. The non-existence of f_XZ and f_XZ 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.

Graphical Abstract

Keywords

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

DOI Link

https://doi.org/10.13208/j.electrochem.201126

Publication Date

2021-10-28

Online Available Date

2021-02-09

Revised Date

2020-12-25

Received Date

2020-11-26

Recommended Citation

Xiang Li, Qiu-An Huang, Wei-Heng Li, Yu-Xuan Bai, Jia Wang, Yang Liu, Yu-Feng Zhao, Juan Wang, Jiu-Jun Zhang. Fundamentals of Electrochemical Impedance Spectroscopy for Macrohomogeneous Porous Electrodes[J]. Journal of Electrochemistry, 2021 , 27(5): 467-497.
DOI: 10.13208/j.electrochem.201126
Available at: https://jelectrochem.xmu.edu.cn/journal/vol27/iss5/4