Abstract
Low methanol and water crossover with high methanol concentrations are essential requirements for a passive Direct Methanol Fuel Cell (DMFC) to be used in portable applications. Therefore, it is extremely important to clearly understand and study the effect of the different operating and configuration parameters on the cell’s performance and both methanol and water crossover. In the present work, a detailed experimental study on the performance of an in-house developed passive DMFC with 25 cm2 of active membrane area is described. Tailored membrane electrode assemblies (MEAs) with different structures and combinations of gas diffusion layers (GDL) and membranes, were tested in order to select optimal working conditions at high methanol concentration levels without sacrificing performance. The experimental polarization curves were successfully compared with the predictions of a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the passive DMFC developed by the same authors.
Highlights
In the past few years, energy needs for portable electronic devices are rising rapidly due to the increasing amount of applications, especially cell phones
In a previous work Oliveira, Rangel and Pinto (2011) developed a onedimensional model considering the effects of coupled heat and mass transfer, along with the electrochemical reactions occurring in a passive direct methanol fuel cells (DMFC)
The model is a useful tool to predict the influence of the different operating and design parameters on fuel cell performance and to estimate the methanol crossover rate and the water flux through the membrane, quantified in terms of a net water transport coefficient (α)
Summary
In the past few years, energy needs for portable electronic devices are rising rapidly due to the increasing amount of applications, especially cell phones. Conventional batteries are soon becoming inadequate for the increasing power demand and complexity of portable electronics devices. The time these portable devices can operate as truly portable is limited by the quantity of energy that can be stored within the batteries. The DMFC are capable of replacing the conventional batteries due to their high energy density and inherent simplicity of operation with methanol as the liquid fuel. This system is more performant, less expensive, environmentally safer, much more efficient and can be used either in a plane, train, car or in remote areas where there is no electricity. The fuel is supplied to the anode from a fuel reservoir built-in in the anode and the air to the cathode, normally by natural
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