Micro porous layer

In-situ measurement technique of water vapor concentration in gas flow channels in PEMFCs using tunable diode laser absorption spectroscopy (TDLAS)31-36 is also shown with fundamental descriptions on its measuring principle and validity of a practical system. Localized current density and through-plane water-back transport index are obtained with variation of vapor concentration along the gas channel taken into account. Demonstrative results showing that effect of the micro porous layer (MPL) on variation of through-plane water-back transport index is shown in an operating PEMFC. 

Pasaogullari, U. and Wang, C.-Y., Two-phase transport and the role of micro-porous layer in polymer electrolyte fuel cells, Electrochim. Acta, 49, 4359, 2004. 

Technology of the reverse meniscus consists in imposition of micro-porous layer to the PIN-structure that provides high intensity of heat transfer. Using of bidisperse wick structure is also instrumental in intensification of heat transfer. 

Wang X, Zhang H, Zhang J, Xu H, Tian Z, Chen J, Zhong H, Liang Y, Yi B (2006) Micro-porous layer with composite carbon black for PEM fuel cells. Electiochim Acta 51 4909-4915... 

Gas Diffusion Layers (GDLs) and the Micro Porous Layers (MPLs). This can affect the alcohol and water management in the cell and thus the electrochemical performance ... 

Wang, X., Zhang, H., Zhang, J. etal (2006) Investigation of the role of the micro-porous layer in polymer electrolyte fuel cells with hydrogen deuterium contrast neutron radiography. J. Power Sources, 162, 474-479. 

Hydrophobic treatment (HT) and micro-porous layer (MPL) in addition to gas diffusion layer (GDL) effect on water balance... 

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

Y. Fujii, S. Tsushima, S. Hirai, Effect of micro porous layer on membrane hydration path under low humidity operation of PEMFC, ECS Trans. 25 (2009) 1783-1789. 

B., Phoenix, A., Halliop, E., and Pharoah, J. (2007) Experimental investigation of the role of a micro-porous layer on the water transport and performance of a PEM fuel cell. J. Power Sources, 170 (1), 111-121. 

The state-of-the-art gas diffusion media are hydrophobized to such an extent that they allow transport of liquid water, an important mechanism at near-saturated conditions, as well as of water vapor and reactant gases. An important role is played by the micro porous layer (MPL). Because of the presence of small hydrophobic pores, a substantial hquid water capillary pressure can be bruit up, enabling a good gradient in the chemical potential of water to drier sections [10]. The optimization of gas diffusion media and the application of the MPL have led to significant improvement of the fuel cell performance at saturated conditions, showing their critical role. 

Tang H, Wang S, Pan M, Yuan R. Porosity-graded micro-porous layers for potymer electrolyte membrane fuel cells. J Power Sources 2007 166(l) 41-6. 

GMPL graded porosity micro-porous layer... 

In this chapter, the electrode construction of a high temperature (HT) polymer electrolyte membrane (PEM) electrode assembly (MEA) will be explained. The different functionalities of the electrode layers like the gas diffusion layer (GDL), the micro porous layer (MPL), and the... 

Dai W, Wang H, Yuan X Z, Martin J, Shen letal. (2009a), Measurement of water transport rates across the gas diffusion layer in a proton exchange membrane fuel cell, and the influence of polytetrafluoroethylene content and micro-porous layer . Journal of Power Sources, 188, 1, 122-126. 

Kang K and Ju H (2009), Numerical modeling and analysis of micro-porous layer effects in polymer electrolyte fuel ceAXs, Journal of Power Sources, 194,2,763-773. 

Wu, R., Zhu, X., Liao, Q., 2010, A pore network study on the role of micro-porous layer in control of liquid water distribution in gas diffusion layer , Int. J. Hydrogen Energy, 35 (14) pp. 7588. 

WATER TRANSPORT THROUGH MICRO-POROUS LAYERS (MPL)... 

As illustrated in Figure 1.2, one side of the cathode GDL facing to the catalyst layer is generally provided with a micro-porous layer (MPL) of polytetrafluoroethylene (PTFE) with hydrophobic characteristics. It has much smaller pores and a much smoother surface than the GDL. The MPL plays an important role in the water management of polymer electrolyte fuel cells however, details of the meehanism that works to suppress water flooding are not fully understood. Questions still remain about whether the water transfer in the MPL occurs in the liquid or vapor phase. 

Chikahisa, T., Tabe, Y. Kadowaki, K. Study on water transport phenomena through micro-porous layers in PEFC. Proceedings of theASME 10th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2012-73063, 2012, pp. 1-7. 

Hizir, RE., Ural, S.O., Kumbur, E.C. Mench, M.M. Characterization of interfacial morphology in polymer electrolyte fuel-cells Micro-porous layer and catalyst layer surfaces. J. Power Sources 195 (2010), pp. 3463-3471. 

Fig. 13.3 Microstructure of MBA interface showing membrane, catalyst and micro porous layer...

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