Extended direct methanol fuel cell

Another important future area for diffusion layers is the use of three-dimensional catalyzed diffusion layers for liquid-based fuel cells. This allows the three-phase active zone to be extended into the diffusion layer to increase performance and utilization and reduce crossover [276,277]. Recent work by Lam, Wilkinson, and Zhang [278] has shown the scaleable use of this concept to create a membraneless direct methanol fuel cell. In other work by Fatih et al. [279], the... 

A. Bauer, E. L. Gyenge, and C. W. Oloman. Direct methanol fuel cell with extended reaction zone anode PtRu and PtRuMo supported on graphite felt. Journal of Power Sources 167 (2007) 281-287. 

Joo and co-workers [22] have discussed a new type of composite membrane, consisting of functionalised carbon nanotubes (CNT) and sulfonated polyarylene sulfone (sPAS) for direct methanol fuel cell applications. The CNT modified with sulfonic acid or platinum-rubidium (PtRu) nanoparticles were dispersed within the sPAS matrix by a solution casting method to give SOs-CNT-sPAS or PtRu-CNT-sPAS composite membranes, respectively. Characterisation of the composite membranes revealed that the functionalised CNT were homogeneously distributed within the sPAS matrix and the composite membranes contained smaller ion clusters than the neat sPAS. The composite membranes exhibited enhanced mechanical properties in terms of tensile strength, strain and toughness, which leads to improvements in ion conductivity and methanol permeability compared with the neat sPAS membrane, which demonstrates that the improved properties of the composite membranes induce an increase in power density. The strategy for CNT-sulfonated composite membranes in this work can potentially be extended to other CNT-polymer composite systems. 

Steckmann, K. (2009) Extending EV range with direct methanol fuel cells. World Electr. Veh.J., 3 (EVS24), 1-4. 

Figure 4.65. Performance comparison of DMFC equipped with extended reaction zone anode composed of pressed graphite felt with PtRu and PtRuMo, obtained by electrodeposition from a colloidal solution [86, 250], a) 333 K, b) 343, and 353 K. Anode catalyst characteristics are given in Table 4.4. Anolyte 1 M CH3OH - 0.5 M H2SO4, 5 mL min, ambient pressure. Cathode 4 mg cm Pt black, O2 flow rate 500 nil min at 2 atm (abs). [86]. (Reprinted from Journal of Power Sources, 167(2), Bauer A, Gyenge EL, Oloman CW, Direct methanol fuel cell with extended reaction zone anode PtRu and PtRuMo supported on graphite felt, 281-7, 2007, with permission from Elsevier.)...

In addition to carbon and graphite-based extended reaction zone supports, Ti mesh has been fairly extensively investigated for direct methanol fuel cells in both acid and alkaline conditions, and also for formic acid cells [218, 305-307, 309-313]. Compared to three-dimensional carbons, Ti mesh has the advantage of a... 

Figure 4.62. Examples of three-dimensional supports for extended reaction zone anodes in direct liquid fuel cells, (a) unpressed graphite felt UGF, (h) pressed graphite felt GF, (c) reticulated vitreous earhon RVC [250, 305]. (Reprinted from Electrochimica Acta, 51(25), Bauer A, Gyenge EL, Oloman CW, Eleetrodeposition of Pt-Ru nanoparticles on fibrous carbon substrates in the presence of nonionie surfactant Apphcation for methanol oxidation, 5356-64, 2006, with permission from Elsevier, and reproduced by permission of ECS— The Electrochemical Society, Gyenge EL, Oloman CW. The surfactant-promoted electroreduction of oxygen to hydrogen peroxide.)...

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