Proton exchange membrane (PEM) fuel cells hold the promise of environmentally
friendly power generation due to their low/zero emissions in comparison with
internal combustion engines. PEM fuel cells also have several other advantages
over conventional energy converting devices, including both high efficiency and
power density, which make them unique across a wide range of portable,
stationary, and transportation power applications. However, several challenges
remain, including cost and reliability/durability. Intensive R&D is therefore still
needed to address these challenges in order to achieve sustainable
commercialization. In this ongoing R&D, fuel cell testing and diagnostics play a
critical role in material characterization, performance optimization, design
validation, and fundamental understanding for further development. Among the
testing and diagnostic tools used in fuel cell R&D, AC impedance spectroscopy (or
electrochemical impedance spectroscopy, EIS) is regarded by scientists and
engineers as a powerful technique.