Fuel cell gas diffusion layer

K. T. Jeng, S. E. Lee, G. E. Tsai, and C. H. Wang. Oxygen mass transfer in PEM fuel cell gas diffusion layers. Journal of Power Sources 138 (2004) 41-50. 

Lim, C. Wang, C. Y. Measurement of contact angles of liquid water in PEM fuel cell gas diffusion layer (GDL) by sessile drop and capillary rise methods. Penn State University Electrochemical Engine Center (ECEC) Technical Report no. 2001 03, Perm State University State College, PA, 2001. 

Kramer D et al (2008) Electrochemical diffusimetry of fuel cell gas diffusion layers. J Electroanal Chem 612 63-77... 

Kleemann J, Finsterwalder F, Tillmetz W (2009) Characterisation of mechanical behaviour and coupled electrical properties of polymer electrolyte membrane fuel cell gas diffusion layers. J Power Sources 190 92-102... 

FIGURE 5.4 Calculated electrical conductivity as a function of applied compressive load. The values were calculated based on the data reported by Kleemann et al. (2009). (Reprinted from the Journal of Power Sources, 190, Kleemann, J., Finsterwalder, F., and Tillmetz, W. Characterisation of mechanical behaviour and coupled electrical properties of polymer electrolyte membrane fuel cell gas diffusion layers. Selected Papers presented at the 11th ULM Electrochemical Days, 92-102, Copyright (2009), with permission from Elsevier.)... 

D. P. Das, Liquid water-droplet adhesion-force measurements on fresh and aged fuel-cell gas-diffusion layers,/. Electrochem. Soc., 159, B489-B496 (2012). 

Sadeghi, E., Djilali, N., and Bahrami, M. 2008. Analytic determination of the effective thermal conductivity of PEM fuel cell gas diffusion layers. 1 200-208. 

S. Litster, D. Sinton, and N. DjUah, Ex situ Visualization Liquid Water Transport in PEM Fuel Cell Gas Diffusion Layers, /. Power Sources, Vol. 154, pp. 95-105, 2006. 

Properties of Typical Fuel Cell Gas Diffusion Layers... 

Figure 4.33. Equivalent circuit of a catalyst layer [8]. (Reproduced by permission of the authors and of ECS—The Electrochemical Society, from Lefebvre MC, Martin RB, Pickup PG. Characterization of ionic conductivity within proton exchange membrane fuel cell gas diffusion electrodes by impedance spectroscopy.)...

C. Boyer, S. Gamhurzev, O. Velev, S. Srinivasan, and A.J. Appleby. Measurements of proton conductivity in the active layer of PEM fuel cell gas diffusion electrodes. Electrochimica Acta 43, 3703-3709 1998. 

In polymer electrolyte membrane fuel cells, like in many other kinds of fuel cells, gas-diffusion electrodes are used. They consist of a porous, hydrophobic gas-diffusion layer (GDL) and of a catalytically active layer. The diffusion layers (often called backing layers) usually consist of a mixture of carbon black and about 35% by mass of polytetrafluoroethylene (PTFE) applied to a conducting base (most often a thin graphitized cloth). The GDLs yield a uniform supply of reactant gas... 

The main components of a PEM fuel cell are the flow channels, gas diffusion layers, catalyst layers, and the electrolyte membrane. The respective electrodes are attached on opposing sides of the electrolyte membrane. Both electrodes are covered with diffusion layers, and the flow channels/current collectors. The flow channels collect current from the electrodes while providing the fuel or oxidant with access to the electrodes. The gas diffusion layer allows gases to diffuse to the electro-catalysts and provides electrical contact throughout the catalyst layers. Within the anode catalyst layer, the fuel (typically H2) is oxidized to produce electrons and protons. The electrons travel through an external circuit to produce electricity, while the protons pass through the proton conducting electrolyte membrane. Within the cathode catalyst layer, the electrons and protons recombine with the oxidant (usually 02) to produce water. 

An analysis of the individual PEM components offers evidence of almost unbroken R D see Fig. 13.10 (Jochem et al., 2007). The overall importance of the membrane is striking. Furthermore, the numbers of annual applications for bipolar plates (BPP) and the gas-diffusion layer (GDL) decrease after 2002, while the increase in membrane applications flattens out. This correlates with the equally lower number of fuel cell patents in the field of mobile applications. 

CNF is an industrially produced derivative of carbon formed by the decomposition and graphitization of rich organic carbon polymers (Fig. 14.3). The most common precursor is polyacrylonitrile (PAN), as it yields high tensile and compressive strength fibers that have high resistance to corrosion, creep and fatigue. For these reasons, the fibers are widely used in the automotive and aerospace industries [1], Carbon fiber is an important ingredient of carbon composite materials, which are used in fuel cell construction, particularly in gas-diffusion layers where the fibers are woven to form a type of carbon cloth. 

Figure 2.1 shows a schematic structure of the fuel cell membrane electrode assembly (MEA), including both anode and cathode sides. Each side includes a catalyst layer and a gas diffusion layer. Between the two sides is a proton exchange membrane (PEM) conducting protons from the anode to the cathode. 

Antoine et al. [28] inveshgated the gradient across the CL and found that the Pt utilization was dependent on the CL porosity. In a nonporous CL, catalyst utilization was increased through the preferential locahon of Pt close to the gas diffusion layer in a porous CL, catalyst utilization efficiency was increased through the preferential location of Pt close to the polymer electrolyte membrane. In PEM fuel cells, fhe CL has a porous structure, and better performance is expected if higher Pf loading is used af preferential locahons close to the membrane/catalyst layer interface. 

For example, if fhe DL is used on the side of fhe cell where fhe fuel or oxidant is in gas phase, then this part can be referred to as gas diffusion layer (GDL). When bofh fhe CL and the DL are mentioned as one component, then the name "diffusion electrode" is commonly used. Because the DL is of a porous nature, it has also been called "diffusion medium" (DM) or "porous transporf layer" (PTL). Sometimes the DL is also referred to as fhe component formed by an MPL and a backing layer. The MPL has also been called the "water management layer" (WML) because one of its main purposes is to improve the water removal inside the fuel cell. In this chapter, we will refer to these components as MPL and DL because these names are widely used in the fuel cell indusfry. 

T. H. Ko, Y. K. Liao, and C. H. Liu. Effects of graphitization of PAN-based carbon fiber cloth on its use as gas diffusion layers in proton exchange membrane fuel cells. New Carbon Materials 22 (2007) 97-101. 

A. Hamada and K. Nakato. Gas diffusion layer for fuel cell and manufacturing method of the same. US Patent 2002068215 (2002). 

F. Y. Zhang, S. G. Advani, and A. K. Prasad. Performance of a metallic gas diffusion layer for PEM fuel cells. Journal of Power Sources 176 (2008) 293-298. 

M. S. Yazici and D. Krassowski. Development of a unique, expanded graphite gas diffusion layer for PEM fuel cells. Fuel Cell Seminar Proceeding Fuel Cell Progress, Challenges and Markets. Fuel Cell Seminar Palm Springs CA, Nov. 14-18 (2005), 117-120. 

K. Jiao and B. Zhou, hmovative gas diffusion layers and their water removal characteristics in PEM fuel cell cathode. Journal of Power Sources 169 (2007) 296-314. 

M. V. Williams, H. R. Kunz, and J. M. Fenton. Operation of Nafion(R)-based PEM fuel cells with no external humidification Influence of operating conditions and gas diffusion layers. Journal of Power Sources 135 (2004) 122-134. 

N. Holmstrom, J. Ihonen, A. Lundblad, and G. Lindbergh. The Influence of the gas diffusion layer on water management in polymer electrolyte fuel cells. Fuel Cells 7 (2007) 306-313. 

C. Xu, T. S. Zhao, and Y. L. He. Effect of cathode gas diffusion layer on water transport and cell performance in direct methanol fuel cells. Journal of Power Sources 171 (2007) 268-274. 

V. Gurau, M. J. Bluemle, E. S. De Castro, et al. Characterization of transport properties in gas diffusion layers for proton exchange membrane fuel cells. 2. Absolute permeability. Journal of Power Sources 165 (2007) 793-802. 

H. Nakajima, T. Konomi, and T. Kitahara. Direct water balance analysis on a polymer electrolyte fuel cell (PEFC) Effects of hydrophobic treatment and microporous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation. Journal of Power Sources 171 (2007) 457-463. 

E. Antolini, R. R. Passos, and E. A. Ticianelli. Effects of the cathode gas diffusion layer characteristics on the performance of polymer electrolyte fuel cells. Journal of Applied Electrochemistry 32 (2002) 383-388. 

A. M. Kannan, A. Menghal, and 1. V. Barsukov. Gas diffusion layer using a new type of graphitized nanocarbon PUREBLAGK(R) for proton exchange membrane fuel cells. Electrochemistry Communications 8 (2006) 887-891. 

A. M. Kannan, L. Cindrella, and L. Munukutla. Functionally graded nanopo-rous gas diffusion layer for proton exchange membrane fuel cells under low relative humidity conditions. Electrochimica Acta 53 (2008) 2416-2422. 

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