4D in situ visualization of mechanical degradation evolution in reinforced fuel cell membranes

February 22, 2020

Dilip Ramani (1), Yadvinder Singh (1), Robin T. White (1), Matthew Wegener (1), Francesco P. Orfino (1), Monica Dutta (2), Erik Kjeang (1)

International Journal of Hydrogen Energy, 45, Issue 16, 20 March 2020:10089-10103. DOI: 10.1016/j.ijhydene.2020.02.013


Reinforced membrane; Fuel cell; Fracture; Crack; Visualization; X-ray computed tomography


Composite ionomer membranes with ePTFE reinforcement have been developed to improve operational durability of polymer electrolyte fuel cells by creating a more mechanically robust membrane electrode assembly. The present objective is to determine the morphological damage evolution of a reinforced membrane subjected to pure mechanical degradation by wet/dry cycling in a fuel cell. Identical-location four-dimensional in situ visualization by X-ray computed tomography is used to reveal the progressive degradation stages from initiation via propagation to failure. The observed degradation process is dominated by fatigue driven membrane fracture which is primarily confined under the channel area. When compared to degradation of non-reinforced membranes, the results for the reinforced membrane demonstrate similar non-linear progression of membrane fracture, but at 2-3x lower rate due to the improved fracture resistance of ePTFE reinforcement. Membrane-catalyst layer delamination and catalyst layer cracks are identified as preceding drivers of local membrane fracture, while wet and dry phase in situ imaging demonstrates hydration induced throughplane swelling of 30% and widespread crack closure at advanced degradation states. Overall, these results provide new understanding of mechanical degradation in composite membranes and prospective directions for further durability enhancements.

How Our Software Was Used

Dragonfly was used to visualize and inspect slice-by-slice 2D images.

Author Affiliation

(1) Fuel Cell Research Lab (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
(2) Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC, V5J 5J8, Canada