Increasing fuel cell durability during prolonged and intermittent fuel starvation using supported IrOx

Tita Labi, Francois Van Schalkwyk, Shuang Ma Andersen, Per Morgen, Sekhar Chandra Ray, Jessica Chamier*

*Kontaktforfatter for dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstrakt

Addition of an oxygen evolution reaction (OER) catalyst is a materials approach to mitigate the impacts of potential reversal caused by fuel starvation. In this study Iridium oxide (IrOx) supported on graphitized Vulcan (GV) black (56 wt% Ir) was added as an OER catalyst into the anode of a membrane electrode assembly (MEA) (0.1 mgIr/cm2). When exposed to intermittent 5-, 10- and 30- minutes of starvation, with 10 min recovery periods, the reversed cell potential was clamped at −0.8 V, mitigating severe carbon degradation. The intermittently starved MEAs regained >95% of their initial performance. After the first event, the performance loss was significant at 4% (0.2 A/cm2) with increases in ohmic resistance, thereafter the performance remained relatively stable. Using SEM and EIS, the increased ohmic resistance was attributed to deformation and contraction of the membrane and ionomer reconfiguration which impacted proton conductive pathways. Thinning of the anode was unavoidable, contributing to contact resistance and decreased performance. The Pt and IrOx/GV catalyst remained relatively stable when subjected to multiple short periods of fuel starvation. The IrOx/GV MEA was reversal tolerant and provided insight into the degradation processes which occur during periodic and prolonged fuel starvation.

OriginalsprogEngelsk
Artikelnummer229568
TidsskriftJournal of Power Sources
Vol/bind490
Antal sider7
ISSN0378-7753
DOI
StatusUdgivet - 1. apr. 2021

Bibliografisk note

Funding Information:
We would like to acknowledge the financial support provided by the South African Department of Science and Innovation (DSI) , Danish International Development Agency (DANIDA) , and Catalysis South Africa (CATSA) .

Publisher Copyright:
© 2021 Elsevier B.V.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

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