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A pore network model has been applied to a both sides of a fuel cell membrane electrode assembly. The model includes gas transport in the gas diffusion layers and catalyst layers, proton transport in the catalyst layers and membrane, and percolation of liquid water. This paper presents an iterative algorithm to simulate a steady state isothermal cell with a 3D pore network model for constant voltage boundary condition. The proposed algorithm provides a simple method to couple the results of the anode and the cathode sides by iteratively solving the uncoupled equations of the transport processes. It was found that local water blockages at the GDL/CL interface not only affect concentration polarization, but also might change ohmic polarization of the cell. Depending on the liquid water configuration in the porous electrodes, the protons generated in the anode need to travel longer paths to reach the active sites of the cathode; consequently, the IR loss will be increased in the presence of liquid water. This finding highlights the strength of pore network models which resolve discrete water blockages in the electrodes. Polymer electrolyte membrane fuel cells are one of the key technologies required to realize a sustainable energy economy because they provide energy storage. A typical PEMFC is a stack of electrochemical cells, and the heart of each is a sandwich of several porous layers around a thin polymer electrolyte membrane, referred to as a membrane-electrode assembly (MEA). In the typical arrangement each side consists of a gas diffusion layer (GDL), and a catalyst layer (CL). The GDL is usually a carbon-fiber based paper and acts as a spacer to allow gaseous reactants to reach regions of the catalyst layer under the flow field ribs, and as a bridge to allow electron access to catalyst sites over the flow field channels. The CL is composed of a mixture of ionomer such as Nafion and carbon-supported platinum catalyst particles, and is adhered to the surface of the membrane as a porous coating around 10-20 μm thick. The ionomer phase in the CL allows protons to reach the catalyst sites, while the carbon particles provide pathways for electrons, and the porosity allows transport of gaseous reactants (oxygen and hydrogen) and product (water). Under some conditions the cathode produces liquid water, which can accumulate in the pore spaces, blocking the access to the reaction sites. Liquid water can also be found on the anode side, for instance if temperature fluctuations occur since the hydrogen is humidified. Understanding the role of liquid water and its impact on fuel cell operation has been a longstanding challenge for the industry.1-3 Complete water removal from the cell is not an option because the currently used membrane materials must be hydrated to function.When electrical current is drawn, several sources of voltage loss are incurred due to the inefficiencies of current generation and transport processes. Voltage losses can be broken into three categories: activation polarization η act , ohmic polarizat...

A novel way for anion exchange membrane (AEM) preparation has been investigated, avoiding the use of expensive and toxic chemicals. This new synthetic approach to prepare AEMs was based on the use of a porous polybenzylimidazole membrane as support in which functionalized ILs were introduced and subsequently grafted on the polymer backbone. These new AEMs were prepared and their chemical structures and properties including morphology, thermal stability, and ionic conductivity were characterized. The hydroxyl ionic conductivity of the synthesized membranes can reach values upto 6.62 × 10−3 S cm−1 at 20°C. Although the ionic conductivity is not very high yet, the work shows the strength of the concept. Membrane properties can be easily tailored toward specific applications by choosing the proper chemistry, i.e., porous polymer support, ionic liquid, and method of initiation and polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013