Dynamic electrochemical impedance spectroscopy of Pt/C-based membrane-electrode assemblies subjected to cycling protocols
By Darab, Mahdi; Dahlstrà¸m, Per Kristian; Thomassen, Magnus Skinlo; Seland, Frode & Sunde, Svein
Published in Journal of Power Sources
2013
Abstract
A PEM fuel cell membrane–electrode assembly (MEA) was characterized by dynamic electrochemical impedance spectroscopy (dEIS) before and after cycling in a single cell configuration. The cell was subjected to 100 cycles between 0.6Â V and 1.5Â V vs. RHE in N2/5% H2 and 80 °C and 100% RH. Initially, the impedance-plane plots contained first- and fourth-quadrant behavior, which is resulting from a reaction mechanism at the cathode involving adsorbed intermediates. After the cycling, the impedance spectra changed to display first-quadrant behavior only. This is suggested to be due to particle growth and possibly the formation of edges between agglomerated particles. The results show that dEIS is a sensitive technique to detect even very moderate changes in electrocatalyst structure.