The reasons for the high power density of fuel cells fabricated with directly deposited membranes

JOURNAL OF POWER SOURCES

卷:326

Article

Vierrath, Severin¹  Breitwieser, Matthias^1,2  Klingele, Matthias¹  Britton, Benjamin³  Holdcroft, Steven³  Zengerle, Roland^1,2  Thiele, Simon^1,2,4 

[1] Univ Freiburg, IMTEK Dept Microsyst Engn, Lab MEMS Applicat, Georges Koehler Allee 103, D-79110 Freiburg, Germany

[2] Hahn Schickard, Wilhelm Schickard Str 10, D-78052 Villingen Schwenningen, Germany

[3] Simon Fraser Univ, Dept Chem, 8888 Univ Dr, Burnaby, BC V5A 1S6, Canada

[4] Univ Freiburg, FIT, Georges Koehler Allee 105, D-79110 Freiburg, Germany

关键词: PEM fuel cell;    Direct membrane deposition;    Membrane;    Nafion;    Droplet-on-demand;    Catalyst-coated-membrane;    Membrane-electrode-assembly;   

DOI  :  10.1016/j.jpowsour.2016.06.132

来源: Elsevier

【 摘 要 】

In a previous study, we reported that polymer electrolyte fuel cells prepared by direct membrane deposition (DMD) produced power densities in excess of 4 W/cm(2). In this study, the underlying origins that give rise to these high power densities are investigated and reported. The membranes of high power, DMD-fabricated fuel cells are relatively thin (12 mu m) compared to typical benchmark, commercially available membranes. Electrochemical impedance spectroscopy, at high current densities (2.2 A/cm(2)) reveals that mass transport resistance was half that of reference, catalyst-coated-membranes (CCM). This is attributed to an improved oxygen supply in the cathode catalyst layer by way of a reduced propensity of flooding, and which is facilitated by an enhancement in the back diffusion of water from cathode to anode through the thin directly deposited membrane. DMD-fabricated membrane-electrode-assemblies possess 50% reduction in ionic resistance (15 m Omega cm(2)) compared to conventional CCMs, with contributions of 9 m Omega cm(2) for the membrane resistance and 6 m Omega cm(2) for the contact resistance of the membrane and catalyst layer ionomer. The improved mass transport is responsible for 90% of the increase in power density of the DMD fuel cell, while the reduced ionic resistance accounts for a 10% of the improvement. (C) 2016 Elsevier B.V. All rights reserved.

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