Research direct methanol fuel cells

Despite the uncertainty regarding the exact nature of the active site for oxygen reduction, researchers have managed to produce catalysts based on heat-treated macrocycles with comparable activities to state-of-the-art platinum catalysts. In numerous cases researchers have shown activity close to or better than platinum catalysts.64,71,73,103,109 Since the active site for the ORR in these materials is not fully understood, there is still potential for breakthrough in their development. Another advantage of this class of materials that should be mentioned is their inactivity for methanol oxidation, which makes them better suited than platinum for use in direct methanol fuel cell cathodes where methanol crossover to the cathode can occur.68,102,104,122-124 While the long-term activity of heat treated materials is... 

In electrochemical systems, metal meshes have been widely used as the backing layers for catalyst layers (or electrodes) [26-29] and as separators [30]. In fuel cells where an aqueous electrolyte is employed, metal screens or sheets have been used as the diffusion layers with catalyst layers coated on them [31]. In direct liquid fuel cells, such as the direct methanol fuel cell (DMFC), there has been research with metal meshes as DLs in order to replace the typical CFPs and CCs because they are considered unsuitable for the transport and release of carbon dioxide gas from the anode side of the cell [32]. 

Z. G. Shao, 1. M. Hsing, H. Zhang, and B. Yi. Influence of anode diffusion layer on the performance of a liquid feed direct methanol fuel cell by AC impedance spectroscopy. International Journal of Energy Research 30 (2006) 1216-1227. 

Michael Hickner received his B.S. in Chemical Engineering from Michigan Tech in 1999 and his Ph.D. in Chemical Engineering in 2003 under the direction of James McGrath. Michael s research in Dr. McGrath s lab focused on the transport properties of proton exchange membranes and their structure-property relationships. He has spent time at Los Alamos National Laboratory studying novel membranes in direct methanol fuel cells and is currently a postdoc at Sandia National Laboratories in Albuquerque, NM. 

Direct methanol fuel cell technology is relatively new compared to that of fuel cells powered by pure hydrogen, and research and development are roughly 34 years behind that of other fuel cell types. Nonetheless, the DMFC appears to be the most promising as a battery replacement for portable applications such cellular phones and laptop computers, and a number of manufacturers are already introducing commercial versions of these applications. 

DARPA Defense Advanced Research Project Agency DMFC Direct methanol fuel cell DOE U.S. Department of Energy DR Drain... 

In recent decades, research has intensified to develop commercially viable fuel cells as a cleaner, more efficient source of energy, due to the global shortage of fossil fuels. The challenge is to achieve a cell lifetime suitable for transportation and stationary applications. Among the possible fuel cell types, it is generally believed that PEM fuel cells hold the most promise for these uses [10, 11], In order to improve fuel cell performance and lifetime, a suitable technique is needed to examine PEM fuel cell operation. EIS has also proven to be a powerful technique for studying the fundamental components and processes in fuel cells [12], and is now widely applied to the study of PEM fuel cells as well as direct methanol fuel cells (DMFCs), solid oxide fuel cell (SOFCs), and molten carbonate fuel cells (MCFCs). 

S. C. Thomas, X. Ren, S. Gottesfeld and P. Zelenay, Direct Methanol Fuel Cells Progress in Cell Performance and Cathode Research, Electrochim. Acta 2002, 47, 3741. 

In the past year, we have come considerably closer to the introduction of new ionomeric membranes into direct methanol fuel cells. Most of our membrane/MEA research has focused on the BPSH polymer (collaboration with Virginia Tech). We have found that membrane proeessing, such as boiling in acidic aqueous solutions, greatly affects the polymer morphology, ability to partially block methanol crossover and, consequently, selectivity in DMFC operation. Once proeessed, membranes with... 

DMFC research at LANE in FY 2002 has focused primarily on fundamental issues relevant to potential portable and transportation applications of direct methanol fuel cells, such as cathode and anode electrocatalysis, electrode composition and structure, membrane properties and MEA design. Substantial progress has been achieved in cathode research. 

Patit P. Kundu is Professor in the Department of Polymer Science Technology at Calcutta University, India. He obtained his PhD in 1997 from IIT, Kharagpur, India. He has 67 research papers to his credit in international journals along with ten papers in national/international conferences, contributed 2 book chapters, and one patent. His research interest centers on the fields of synthesis and characterization of oil based rubber and nano-composites, microbial fuel cell, direct methanol fuel cell, microbial biodegradation of waste polyolefin fUm, tissue engineering and gene therapy. 

Intense international academic and industrial research efforts have recently placed the direct methanol fuel cell (DMFC) on the brink of commercialization [xi,xii]. The major advantage of the DMFC relative to other fuel cells is the simplicity of... 

The electrical parameters of varieties supplied with a liquid solution are lower than those of the varieties supplied with gases, but research in direct methanol fuel cells was done mainly with liquid supply. This type of fuel cell is much simpler to design and operate, inasmuch as neither a special evaporator nor dual temperature control (for the evaporator and for the reaction zone of the fuel cell) is needed. With the supply of a liquid methanol solution, all risk of the membrane drying out close to the anode side is eliminated. The elimination of heat is also easier with cells having liquid solution supply. All subsequent information on direct methanol fuel cells in the present chapter refers to the variety supplied with liquid water-methanol solution. 

Quite in contrast to polymer electrolyte fuel cells, and despite the large volume of research performed, direct methanol-type fuel cells are still not in commercial production or wide practical use. Indeed, the true performance of direct methanol fuel cells is hard to assess. The experience gathered in the tests of individual samples, performed under a variety of conditions, does not give a clear reliable picture of fuel cell s performance when used for different needs. For such an assessment, one would need statistical data obtained from tests on a sufficiently large number of cells of any single type, and accounting for all cell parameters and test conditions. 

Another potential field of application for direct methanol fuel cells, that of power sources for electric vehicles, is, so far, very remote. A large amount of research and engineering work still has to be done to master this application, mainly, work aiming at improving their technical and economic parameters to solve the particular problems... 

The production volume of direct methanol fuel cells and their long-term testing results are yet insufficient for an estimate of the lifetime of such fuel cells. Even so, the researchers mainly look at all the major reasons giving rise to the gradual performance drop and/or premature failure of these fuel cells. The reasons for performance drop... 

Park YJ, Lee JH, Kang S, Sauk JH, Song I (2008) Mass balance research for high electrochemical performance direct methanol fuel cells with reduced methanol crossover at various operating conditions. J Power Sources 178 181-187... 

The second aim is the miniaturization of devices, oti which has focused the work of many research groups and companies. Thus, in 2004 Toshiba Inc. presented a direct methanol fuel cell with a size of 22 x 56 x 4.5 nun with a small tank of methanol (2 cm in volume and 8.5 g weight) incorporated, with an output power of 100 mW, which, according to the company is sufficient to maintain a mp3 device operating over 20 h [39]. 

In the first chapter, we introduce the concept of methanol economy, as an alternative to the most popular but still elusive hydrogen economy, and we also provide a brief historical description of fundamental research on electrochemical oxidation of methanol and the development of the first alkaline direct methanol fuel cells more than 60 years ago. The operating principles of PEM and alkaline direct alcohol fuel cells are analyzed, as well as their components, configuration, and operation modes, with a final remark on the state of the art of the technology. 

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