The gas diffusion layer (GDL) is an essential element of the electrodes in polymer electrolyte membrane (PEM) fuel cells. The GDL makes electrical contact with the catalyst layers to provide a larger area to carry the electronic current from the catalyst to the bipolar plates reducing the resistance for current flow. The GDL must be porous to permit the flow of reactant gas from the gas flow ch...

In this paper, the wear resistance and antifriction of epsilon phase layer and diffusion layer of gas nitrided D2 steel and M2 steel have been studied. The changes m wear mechanism of epsilon phase under the load from 20N to 200N are analysed. When the load is lighter than 100N, it is mainly oxidizing wear on friction surface. The adhesion, peeling off and abrasive wear appear on friction surfa...

G. Scotti, P. Kanninen, M. Mäkinen, T. Kallio, S. Franssila Department of Micro and Nanosciences, Aalto University School of Science and Technology, P.O. Box 13500, Aalto 00076, Espoo, Finland Department of Chemistry, Aalto University School of Science and Technology, P.O. Box 16100, Aalto 00076, Espoo, Finland Department of Materials Science and Engineering, Aalto University School of Science ...

In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires) as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i) the gas diffusion coefficient inside such arrays, (ii) the time between collisions of molecules with the nano...

output characteristics of fuel cells are affected by a large number of parameters such as geometry, dimensions, construction materials and conditions of supplying fluids. in this paper a mathematical model followed by a two-dimensional numerical approach has been presented to study the fuel cell parametrically. effect of oxygen concentration at gas diffusion layer entrance, temperature and pres...

The POCl3 diffusion process is still a common way to create the pn-junction of Si solar cells. Concerning the screenprinting process, it is necessary to find a compromise between low emitter recombination, low contact resistance and high lateral conductivity. The formation of a homogeneous emitter during the POCl3 diffusion process depends on several diffusion parameters, including duration, te...

A novel metallic porous medium with improved thermal and electrical conductivities and controllable porosity was developed based on micro/nano echnology for its potential application in PEM fuel cells. In this work to demonstrate its applicability, the gas diffusion medium, made of 12.5 m hick copper foil, was tested in an operational fuel cell. The small thickness and straight-pore feature of ...

the thermal diffusion factor, at, for a binary gas mixture is calculated on the basis of nonequilibrium thermodynamics. a new formula for at is derived and this factor is given for several paris of gases according to this formula.

 Recently, special type of fuel cells has been developed that operates in a Dead End mode. Working in this condition, the Dead-End fuel cell is supplied withhydrogen almost at the same rate of consumption. It is noteworthy to mention thatall of the water transport mechanisms have been considered in this simulation.Water accumulation that is directly proportional to the cell current is of a grea...