Direct methanol fuel cells,

Fuel cells are electrochemical devices that convert the chemical energy of the fuels directly into electrical energy, and are considered to be the key technology for power generation in stationary, automotive, portable and even microscale systems. Among all kinds of fuel cells, direct methanol fuel cells have really exhibited the potential to replace current portable power sources and micropower sources in the market (Yao et al., 2006). 

Fig. 13.27. Potential vs. current density plots for state-of-the-art fuel cells, o, proton exchange membrane fuel cell , solid oxide fuel cell , pressurized phosphonic acid fuel cell (PAFC) a, direct methanol fuel cell, direct methanol PAFC , alkaline fuel cell. (Reprinted from M. A. Parthasarathy, S. Srinivasan, and A. J. Appleby, Electrode Kinetics of Oxygen Reduction at Carbon-Supported and Un-supported Platinum Microcrystal-lite/Nafion Interfaces, J. Electroanalytical Chem. 339 101-121, copyright 1992, p. 103, Fig. 1, with permission from Elsevier Science.)...

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. 

Platinum has a myriad of practical uses, especially in the field of electrochemistry where it is used as a catalyst and as a reference electrode. In particular, platinum is the most active known pure metal for the oxygen reduction reaction (ORR) in which O2 is split and combined with protons to form H2O. This is an important step in low-temperature fuel cells (polymer electrolyte fuel cells, direct methanol fuel cells, etc.) as it often is what limits the total fuel cell efficiency. Furthermore, platinum is rather expensive with the materials cost of its use in fuel cells being roughly half of the total fuel cell cost. Consequently, a great deal of effort is made in order to optimize its use. 

Key Words Proton exchange membrane fuel cells. Direct methanol fuel cells. Protonconducting materials, NMR, Magic angle spinning NMR, Pulsed field gradient NMR, Rel-... 

The same concept of combination of an acidic solid polymer electrolyte and acid stable precious metal electrocatalysts can also be applied to a methanol-fed fuel cell (Direct Methanol Euel Cell, DMFC). Methanol can be fed in liquid or vapor form, mixed with water. The methanol molecule CH3OH is electrochemically converted at the anode according to... 

Key words polymer electrolyte membrane fuel cell, direct methanol fuel cell, oxygen reduction, reaction mechanism, core-shell, platinum-fiee. 

Zhao,T.S. Xu,C.L. Fuel-cells-Direct alcohol fuel-cells Direct methanol fuel-cell overview performance and operational conditions. In Encyclopedia of electrochemical power sources. Elsevier, 2009, pp. 381-389. 

A polymer electrolyte is also referred to as a solid solvent that possesses ion transport properties similar to that of the common liquid ionic solution. It usually comprises a polymer matrix and electrolyte, wherein the electrolyte such as a lithium salt dissolves in a polymer matrix. The research and development of polymer electrolytes have drawn great attention in the last three decades as they are applied in many electrochemical devices such as hthium batteries, nickel - metal hydride (Ni/MH) batteries, fuel cells/direct methanol fuel cells, supercapadtors, electrochromic devices and the like (Gray, 1991 Stephan, 2006). 

DCL DDGS DEFC DICI DISI DME DMFC DOE DP DPF Direct coal liquefaction Distillers dried grains with solubles Direct ethanol fuel cell Direct-injection compression ignition Direct-injection spark ignition Dimethylether Direct methanol fuel cell Department of Energy (USA) Dynamic programming Diesel particulate filter... 

Figure 3-8 Single Cell Direct Methanol Fuel Cell Data (45)...

Figure 4.14. Laptop computer powered by a direct methanol fuel cell. The methanol cartridge is at the back. (From Y. Kubo, NEC Corp., (2004). Micro fuel cells for portable electronics. In Proc. 15 World Hydrogen Energy Conf., Yokohama. OlPL-22, Hydrogen Energy Soc. Japan. Used with permission.)...

In automotive applications of fuel cells, where methanol is often considered to be a very attractive fuel, it would be advantageous to be able to oxidize methanol directly at the anode, thus avoiding the necessity of reforming it first. The... 

The fuel cell does not contain its own fuel therefore fuel storage and delivery system are very important to a successful system. One of the first questions that needs to be addressed is whether the fuel cell will operate on hydrogen, reformed fuel, or direct methanol. Another important question is whether the system will be active or passive with regard to the oxidant. 

Calabrese Barton, S. Fuller, T.F. West, A. Electrode design for a strip-cell direct methanol fuel cell. ECS Meeting Abstracts, 1998 ECS, MA 98-2, 1089. 

Barton, S.C., Patterson, T., Wang, E., Fuller, T.F., and West, A.C. (2001) Mixed-reactant, strip-cell direct methanol fuel cells. Journal of Power Sources, 96 (2), 329-336. 

Other fuels (e.g., methanol, ethanol, or other organic molecules), which can be oxidized under moderate conditions of PEMFCs (<373 K at ambient pressure), may be utilized in the place of dihydrogen. A fuel cell where methanol is oxidized at the anode is called a direct methanol fuel cell (DMFC). 

Sulfonated PPESK membrane materials have been demonstrated to be useful for various types of fuel cells, such as formic acid fuel cells, and methanol fuel cells. The direct methanol fuel cell has certain advantages over the proton exchange membrane fuel cell because it is more suitable for portable applications. Because of the interest in these cells, many papers focus on materials suitable for membranes. The reactions in a direct methanol fuel cell are ... 

Methanol is a much more realistic fuel for fuel cells. The specific energy content of methanol when electrochemically completely oxidized to CO2 is 0.84 Ah/g. For fuel cells with methanol as a fuel, acidic electrolyte solutions must be used. Alkaline solutions are inappropriate, as the alkali combines with CO2 produced in the fuel cell to insoluble carbonates. In the early 1960s, first laboratory models of methanol-air fuel cells were built. As large amounts of expensive platinum catalysts were used in these fuel cells, work in this direction soon ended and was not taken up again for many years. 

The performance of different t3 pes of membranes in direct alcohol fuel cells, mainly methanol, are summarized and discussed in order to identify the most promissory ones. The lack of correlatirMi between the relative selectivity and fuel ceU performance of the membranes indicates that the architecture of the three... 

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