Towards a Harmonized Accelerated Stress Test Protocol for Fuel Starvation Induced Cell Reversal Events in PEM Fuel Cells: The Effect of Pulse Duration

Abstract

Global fuel starvation is an undesired event during fuel cell operation that results in serious degradations at the anode catalyst layer caused by the concomitant reversal of the cell potentials. Several groups have therefore intensified their research efforts towards the implementation of suitable diagnostic tools and accelerated stress test (AST) protocols that mimic cell reversal events. However, the current number of different test protocols requires consolidation and harmonization to define durability targets towards cell reversal tolerance and to benchmark newly developed materials. To create a basis for harmonization, this study examines the difference between pulsed and quasi-continuous AST protocols at the catalyst-coated membrane level. Utilizing a single-cell setup combined with an on-line mass spectrometer, a 2.5-fold increase in the carbon corrosion rates were found for short-pulsed compared to long-lasting cell reversal events. The enhanced corrosion was associated with a 2.2-fold higher loss of electrochemically active surface area and a 15% higher reduction in anode catalyst layer thickness. By contrast, the overall cell performance decreased additionally by 40–50 mV for samples under long-lasting cell reversal events. The decay is mainly driven by an increased ohmic resistance, presumably originating from a more pronounced surface oxide formation on the carbon support.