A sieve printing technique has been developed for the preparation of gas diffusion electrodes for proton exchange membrane fuel cells (PEMFCs). The results of the preparation of membrane electrode assemblies (MEAs) are shown to be faster and highly reproducible by using the sieve printing and hot pressing method. These results were compared with those obtained by spray and hot pressing method. The experiments were carried out in a 25 cm2 single PEM fuel cell with platinum loadings of 0.4 mg Pt cm−2 and 0.6 mg Pt cm−2 on the anode and cathode, respectively. Scanning electron microscopy analysis was used to investigate the electrodes’ morphology. The performance of the MEAs was measured by polarization curves. It was observed that the sieve printing technique is highly reproducible and significantly more accurate and faster than the spray one. Sieve printing technique can be easily scaled up and is very adequate for high volume production with low-cost. Such features allow manufacturing large active areas for power stack fabrication. In addition, this deposition technique has produced MEAs with a 39.8% higher power density at 0.6 V when compared with the spray one.

This paper presents a study of single‐channel proton exchange membrane fuel cells (PEMFCs) using computational modeling and simulation. For this analysis, the commercial software COMSOL Multiphysics was used to build a single‐phase isothermal and tridimensional fuel cell model. For the mathematical description of the catalyst layer, the flooded agglomerate model was implemented, and it proved to be more accurate than Butler‐Volmer model, which is the pre‐built model in the software. Such evidence was verified when comparing the polarization curves obtained using both models with an experimental curve. After definition of the model, the main objective of this study was to analyze the influence of the flow channel cross‐section in the water distribution inside the cell, studying rectangular, trapezoidal and hybrid stepped geometries. The fuel cell with stepped channel was equivalent to the trapezoidal cell in all aspects analyzed, and both provided superior water management than the rectangular cell. However, the current generation in the rectangular design was slightly higher. It was noted that the simulation of a tridimensional model provided a better understanding of the regions where higher concentrations of water can occur, and that different flow channel designs can be used to enhance water management.

In the present work two 3‐D models, for the catalytic layer, were employed in order to simulate the responses of a PBI high temperature polymeric membrane fuel cell. The simulations made use of an agglomerate model and a pseudo‐homogenous model, both implemented taking into account the temperature influence over their parameters. The overall simulation was performed also as two models, linked by the variable pressure, one for the whole graphite plate simulating the distribution channels, and the other dealing with the MEA and thereof the catalytic layer. A discussion over the two models was done and the experimental results demonstrated that the pseudo‐homogeneous obtained the better fits.

pelo incentivo e apoio durante o tempo de atividades no CCCH.Ao Mestre Dionísio F. Silva, pelas discussões sobre modelagem, experimentos numéricos e, sobretudo, pela amizade que cultivamos durante o tempo de CCCH.Obrigado pela força e pelo exemplo de otimismo e dedicação.Ao Professor Doutor Douglas Alves Cassiano pelo incentivo e discussões sobre o projeto das placas de distribuição de gases.A Eliana L. Godoi, secretária do CCCH, pelo empenho na solução dos nossos pedidos de compras, impressões de documentos e outros.