J. Electrochem. Sci. Technol., 2022, 13(2), 167-176 - 167 - Electrochemical Impedance Spectroscopy (EIS) Performance Analysis and Challenges in Fuel Cell Applications Bhavya Padha, Sonali Verma, Prerna Mahajan, and Sandeep Arya* Department of Physics, University of Jammu, Jammu, Jammu and Kashmir 180006, India ABSTRACT Electrochemical impedance spectroscopy (EIS) is a unique non-destructive technique employed to analyze various devices in different energy storage applications. It characterizes materials and interfaces for their properties in heterogeneous sys- tems employing equivalent circuits as models. So far, it has been used to analyze the performance of various photovoltaic cells, fuel cells, batteries, and other energy storage devices, through equivalent circuit designing. This review highlights the diverse applications of EIS in fuel cells and specific parameters affecting its performance. A particular emphasis has been laid on the challenges faced by this technique and their possible solutions. Keywords : Electrochemical impedance spectroscopy, Energy storage, Fuel cells Received : 27 December 2021, Accepted : 19 March 2022 1. Introduction The current research on developing efficient energy resources has drawn much interest because of diminishing conventional energy resources (coal and petroleum) and their adverse effects on the environ- ment. Due to environmental degradation and energy problems, a global drive to produce sustainable energy harvesting and storage materials has started. In order to develop clean, environment-friendly, highly efficient, self-sustaining, recyclable, and long service life devices, researchers all around the globe have put dedicated efforts [1]. The most effective methodology for evaluating the performance of energy materials is electrochemical characterization [2]. An electrochemical analyzer is a device that enables electrochemical characterization procedures such as electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge (GCD), and cyclic voltammetry (CV) [3,4]. To acquire the electri- cal response of an electrolytic solution, an electro- chemical cell is employed to host the chemical process and is electrically coupled to the electro- chemical spectrometer. Computer programs particu- larly tailored for EIS testing are used to operate EIS systems. As a result, all system components must be obtained before starting an EIS experiment. A known voltage is transmitted from the working electrode to the counter electrode through an electrolytic solution using a three-electrode setup consisting of working, reference, and counter electrodes. The EIS generates quantitative data that allow for the analysis of small-scale chemical processes at the electrode interface and inside the electrolytic solution. As a result, EIS may be used to determine various dielec- tric and electrical characteristics of components in fuel cells [5]. Electrochemical Impedance Spectroscopy (EIS) is an electrochemical method for measuring a system’s impedance concerning the frequency of an alternat- ing current (ac) potential [6]. EIS is used for identify- ing the electrochemical cell’s impedance [7]. Impedance may be determined by applying a small amplitude sinusoidal (ac) voltage to the electrode arrangement, generating a current wherein amplitude and phase angle are evaluated for the provided sinu- soidal voltage. After that, the impedance is calculated employing Ohm’s law. The latter serves as the basis for the EIS experiment. Studying the various fre- quency ranges is necessary to create an impedance Mini-Review *E-mail address: snp09arya@gmail.com DOI: https://doi.org/10.33961/jecst.2021.01263 This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.