Electrochemically Produced Graphene for Microporous Layers in Fuel Cells

• Published in: ChemSusChem Vol. 9; no. 13; pp. 1689 - 1697
• Main Authors: Najafabadi, Amin Taheri, Leeuwner, Magrieta J., Wilkinson, David P., Gyenge, Előd L.
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 07.07.2016; Wiley Subscription Services, Inc
• Subjects: Carbon black; Constraining; Electric Power Supplies; Electrochemistry; Electrodes; Fuel cells; Graphene; Graphite - chemistry; Humidity; Mass transfer; membranes; microporous materials; Oxides - chemistry; Porosity; Relative humidity; Water management; membranes; fuel cells; electrochemistry; microporous materials; graphene
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201600351

The microporous layer (MPL) is a key cathodic component in proton exchange membrane fuel cells owing to its beneficial influence on two‐phase mass transfer. However, its performance is highly dependent on material properties such as morphology, porous structure, and electrical resistance. To improve water management and performance, electrochemically exfoliated graphene (EGN) microsheets are considered as an alternative to the conventional carbon black (CB) MPLs. The EGN‐based MPLs decrease the kinetic overpotential and the Ohmic potential loss, whereas the addition of CB to form a composite EGN+CB MPL improves the mass‐transport limiting current density drastically. This is reflected by increases of approximately 30 and 70 % in peak power densities at 100 % relative humidity (RH) compared with those for CB‐ and EGN‐only MPLs, respectively. The composite EGN+CB MPL also retains the superior performance at a cathode RH of 20 %, whereas the CB MPL shows significant performance loss. Graphene in action: Graphene microsheets are synthesized and incorporated in microporous layers in polymer electrolytic membrane fuel cells. Significant improvements in power density are obtained through the formation of a graphene and carbon black composite layer. The improvement, which is also maintained at low humidity, is attributed to the high conductivity and unique morphological structure of the composite layer.