Electrochemical impedance spectroscopy as a diagnostic tool for passive direct methanol fuel cells

Passive direct methanol fuel cells (pDMFCs) are a promising power source for portable electronic devices since they achieve higher power densities than the traditional batteries, and use a liquid fuel, methanol, which is easy to handle, storage and distribute. However, some key challenges, such as fuel and water crossover through the membrane and the system durability/lifetime and costs, need to be overcome in order to introduce these systems in the market. The electrochemical impedance spectroscopy (EIS) is used in fuel cell systems as a powerful tool to diagnose the cell behaviour and acquire useful information regarding the different losses that negatively affect the cell performance, towards its optimisation. This paper presents a review of the work developed with pDMFCs using the EIS technique as a diagnostic tool, including the EIS fundamentals and the equivalent electric circuit concept. (C) 2022 The Author(s). Published by Elsevier Ltd.