Papers by Keyword: PEM Fuel Cell

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Authors: Pouya Pashaie, Mohsen Shakeri, Reza Miremadeddin
Abstract: Among several hydrogen storage methods for application in fuel cells, on-board hydrogen generation using sodium borohydride (NaBH4; a chemical hydride) for application in proton exchange membrane (PEM) fuel cells can be considered as a low-weight method for portable applications. In this paper, an integrated continuous-flow system for on-demand hydrogen generation from the hydrolysis reaction of the NaBH4 solution in the presence of a low-cost catalyst is proposed. By using the prepared non-noble Co(NO3)2 on porous alpha-alumina support, as catalyst, the cost of the catalyst has cut down considerably. Up to 15 SLPM high-purity hydrogen gas is expected to be generated by this system to supply to a 1 kW-scale proton exchange membrane (PEM) fuel cell stack (H2-air, 40% efficiency).
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Authors: Azizul bin Mohamad
Abstract: This paper evaluate previous experimental studies on sub-freezing start up of proton exchange membrane (PEM) fuel cell system, and identify issues for further investigation. In a successful cold start, product water from electrochemical reaction in the cathode must be removed from the cell before it turns into ice and causing voltage drop and shutdown also leads to permanent damage to fuel cell components. Successful single PEM fuel cell start up was achieved from temperature as low as-30°C. Some researchers found that cold start of a 30 W stack from-20°C was possible only with aid of external energy. Successful self-start up a 2 kW stack from temperature-5°C was reported but the time taken was unacceptably long and attempts to start up the stack at lower temperatures were failed. Based on the current state of research, further research is necessary to fully understand the operation and mechanism of PEM fuel cell cold start.
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Authors: S. M. Javaid Zaidi
Abstract: Fuels are being considered an as environmental friendly technology and are making headlines across the globe as clean and reliable alternate energy source for transportation, stationary and portable power applications. The rapid developments taking place in all the leading research laboratories in the world are making fuel cell closer to the realization. The progress of PEM fuel cell is closely related to the development of solid polymer electrolyte membranes as it defines the properties needed for other components of the fuel cell. So far perfluorosulfonated membranes such as Nafion have been found useful in these fuel cells and are the only material of choice available commercially. But these membranes are very expensive and have other drawbacks, which acts as an impediment for the commercialization of this technology. As a result alternative cheaper membrane materials have been developed. For the development of new or novel membranes mainly three strategies have been used: (1) modifying the currently used ionomer membranes (2) synthesizing new polymeric membranes and (3) develop new polymer composites by blending the two polymers or composting with an inorganic material. The composite membrane approach (3) has been widely used to tackle the problem of methanol crossover and temperature stability.
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Authors: Guo Li, Jin Zhu Tan, Jian Ming Gong
Abstract: Silicon rubber is a potential material for gaskets in proton exchange membrane (PEM) fuel cell. So its long term stability and durability is crucial to the electrochemical performance of fuel cell especially in an acidic, high temperature, humid environment. In present paper, the aging process of silicon rubbers has been studied in one simulated PEM fuel cell medium and two accelerated durability test (ADT) mediums for short time test at 70oC and 90oC, respectively. Effect of exposure time, temperature and exposure medium on aging of silicone rubber is also compared. Weight loss is measured by electronic balance; topographical changes on samples’ surfaces are monitored by optical microscopy; Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was employed to study the surface chemistry of samples before and after exposure over time. The results show that the weight loss increased over time. Surface conditions of samples change over time from initially smooth to rough, crack appearance and finally crack propagation through Optical microscopy. ATR-FTIR results show that the surface chemistry changed significantly via de-crosslinking and chain scission in the backbone for materials over time. The aging degree is severe at high temperature or in high concentration acidic solution over time.
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Authors: Zhi Jun Peng, Pattarapong Choopanya
Abstract: It is the objective of this study to present the 3-dimensional comprehensive computational fuel cell dynamics (CFCD) model of a scaled-down single PEM cell featuring a nominal active surface of 0.0004 m2 for both conventional and serpentine flow field designs. The performance of these two designs are then analysed and compared keeping both anode and cathode inlet gases fully humidified. Then the parallel flow field was modelled under different inlet gas relative humidities (RHa/RHc) representing saturated, moderate, and dry conditions to observe the gain in cell performance. The higher pressure drop of the serpentine flow-field was demonstrated and the magnitude of which might seem to be negligible in the range of 100 Pascal. The simulation results show that a parallel flow-field design with appropriate humidity level can compete with the serpentine counterpart and gives considerably lower pressure drop across the cell. With a grid-independency analysis, it is suggested for the computational power available, the percentage error of important variables (species concentration and averaged current density) between the reference and finer mesh is negligible (< 3%) and the solution time is considerably less.
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Authors: T.A.B. Santoro, Almir Oliveira Neto, Rubens Chiba, Emília Satoshi Miyamaru Seo, E.G. Franco
Abstract: Pt/rare-earth cathode catalysts were synthesized by the alcohol-reduction process and its structure was investigated by transmission electron microscopy (TEM), energy dispersive analyses (EDS), X-ray Diffraction (XRD). The electrochemical behavior of the cathode catalyst was analyzed by cyclic voltammetry (CV) chronoamperommetry (CA).
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Authors: T. Maiyalagan, Sivakumar Pasupathi
Abstract: Fuel cells, as devices for direct conversion of the chemical energy of a fuel into electricity by electrochemical reactions, are among the key enabling technologies for the transition to a hydrogen-based economy. Among the various types of fuel cells, polymer electrolyte membrane fuel cells (PEMFCs) are considered to be at the forefront for commercialization for portable and transportation applications because of their high energy conversion efficiency and low pollutant emission. Cost and durability of PEMFCs are the two major challenges that need to be addressed to facilitate their commercialization. The properties of the membrane electrode assembly (MEA) have a direct impact on both cost and durability of a PEMFC. An overview is presented on the key components of the PEMFC MEA. The success of the MEA and thereby PEMFC technology is believed to depend largely on two key materials: the membrane and the electro-catalyst. These two key materials are directly linked to the major challenges faced in PEMFC, namely, the performance, and cost. Concerted efforts are conducted globally for the past couple of decades to address these challenges. This chapter aims to provide the reader an overview of the major research findings to date on the key components of a PEMFC MEA.
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Authors: Jun Tan, Yao Chuan Qian, Ru Xin Xing, Zhong Xiang Hu
Abstract: Pb/Ni multilayer coatings, with either Pb or Ni as the top layer, were brush plated on ANSI 304 stainless steel to improve its performance as bipolar plates in polymer electrolyte membrane fuel cells (PEMFC). Surface morphology and cross-sectional microstructure of the coatings were characterized with scanning electron microscope (SEM) and optical microscope, respectively. The corrosion resistance of brush plated coatings in a simulated PEMFC environment was investigated using both three-electrode method and immersion of 300 h. Coating surfaces after the immersion were characterized with energy dispersive X-ray spectrometer (EDS). The results show that the multilayer coatings were smooth, dense, and small in grain size with clear layered structure. In the simulated PEMFC environment, the corrosion of multilayer coatings was mainly uniform corrosion. Coatings with different top layers exhibit different corrosion behaviors. Ni layer was corroded preferentially as the anode while the Pb layer was protected.
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Authors: Thomas Luschtinetz, Andreas Sklarow, Johannes Gulden
Abstract: Liquid organic hydrogen carriers (LOHC) are a promising form to store hydrogen. However, the process of dehydrogenation has to be demonstrated for applications with proton exchange membrane (PEM) fuel cells which require very pure hydrogen. Here we document the measured degradation effects due to CO contamination on a PEM fuel cell that is supplied with hydrogen from a LOHC and we want to use later in a maritime application.
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Authors: Mohammad Javad Jazaeri, John Andrews
Abstract: The focus of this paper is to develop and test a modified design of the conventional parallel flow channel configuration in a proton exchange membrane (PEM) fuel cell. One of the main objectives in designing flow channel configurations is to achieve a uniform distribution of reactants across the catalyst layer of the membrane electrode assembly of the fuel cell. Uniform reactant distribution promotes an even current density distribution, and enhances power output and overall cell performance. A simple method for visualizing the flow distribution is used to study the flow distribution in the flow channels of a PEM fuel cell. In the experiment the principle of dimensional analysis and similitude was employed to study gas distribution by using water instead of gas. The results demonstrate that providing storage volumes before the channels creates a better flow distribution. The results also reveal that channels with the shortest distance between inlet and outlet manifold are reactant rich and are filled prior to the channels with longer such distances.
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