Faculty of Chemical Engineering

We have developed a unique method to analyze impedance spectroscopy (EIS) results. Our approach involves transforming the data from the frequency domain to the time domain, using an innovative program based on evolutionary programming. This program is designed to find the most suitable distribution function of relaxation times (DFRT, a.k.a. DRT), a concept we’ll explain briefly here at the end. Moving forward, we want to further develop it in a few directions:

• To transform it from Matlab to Python (in progress already)
• To make it run much faster (in progress already, but can be further improved)
• To adopt it to several electrochemical systems, notably to new kinds of fuel cells, supercapacitors, and batteries.

What is EIS? We take a system and apply ac stimulus to it. The ratio between the voltage and the current is the impedance. For each frequency, it can be presented as a complex number (that is, by real and imaginary parts; other representations are also possible). Scanning the impedance over several orders of magnitude of frequencies is called impedance spectroscopy (or, electrochemical impedance spectroscopy, EIS). Now, once you have the data, the next question is how to interpret it. Most people are looking for an equivalent circuit that could generate similar results. NOT US! We try to do much better than that. Join us and see for yourself.                                                                                                                                   Why is this important? We want to save the world, and for that, humanity must develop new ways to produce and consume energy and reduce greenhouse gas emissions to net zero. Electrochemical devices (fuel cells, batteries, supercapacitors, electrolyzers) must be an essential part of the energy portfolio. EIS is an essential tool for developing those, examining parts of them, examining electrochemical systems, and studying their degradation processes. And who knows how to interpret EIS results correctly? Seriously? Go to start!