Fuel cell evaluation

The bicontinuous-microemulsion polymerization technique has also been used to develop novel proton exchange membranes (PEM) for fuel cell evaluation [97]. A series of hydrocarbon-based membranes were prepared based on the formulation shown in Fig. 5, with additional ionic vinyl monomers such as VB-SLi or bis-3-sulfopropyl-itaconic acid ester. After polymerization, the membranes were treated with dilute H2SO4 (0.5 M) to convert them to PEM membranes. The good performance of these PEM membranes in a single fuel cell is illustrated in Fig. 9. 

M. Ruge and F.N. Btichi, PE fuel cells evaluation of concepts for a bipolar plate design and construction. Proceedings - Electrochemical Society, 2001, pp. 165-173. 

Silva, V.S., Ruffmann, B., Silva, H., Silva, V.B., Mendes, A., Madeira, L.M. and Nunes, S. 2006. Zirconium oxide hybrid membranes for direct methanol fuel cells—Evaluation of transport properties. / Memfo 5cT 284 ... 

Fuel Cell Evaluation ofWC and Pt/WC Nanoparticle Anode Electrocatalysts... 

Stottlemyer AL, Weigert EC, Chen JG (2011) Tungsten carbides as alternative electrocatalysts from surface science studies to fuel cell evaluation. Ind Eng Chem Res 50 16-22... 

Mamlouk M, Kumar SM, Gouerec P, Scott K (2011) Electrochemical and fuel cell evaluation of Co based catalyst for oxygen reduction in anion exchange polymer membrane fuel cells. J Power Sources 196 7594—7600... 

NOj is one of the main air pollutants, emitted mainly from internal eombustion engine vehicles. The NO,c concentration in air fluetuates, espeeially in an urban environment. During rush hour traffic, the NO coneentration is mueh higher than at other times of the day. The eoncentration ehange may result in eonfusion during fuel cell evaluation when comparing data obtained at different sites or different times on the same day. 

Su H, Pasupathi S, Bladergoen B et al (2013) Optimization of gas diffusion electrodes for polybenzimidazole-based high temperature proton exchange membrane fuel cell evaluation of polymer binders in catalyst layer. Int J Hydrogen Energy 38 11370-11378... 

The preparation of MEAs constimtes a vital part of fuel cell evaluation, with the performance of the fuel cell strongly dependent on the quality of the MEA prepared. The MEA consists of the PEM of a given thickness (usually between 25 and 200 pm), two electrodes made from Pt or Pt-Ru alloys (either as unsupported blacks or supported on carbon) combined with an ionomeric binder, and porous gas diffusion layers (GDLs) to facilitate reactant gas transport to the electrodes. The electrodes may be directly apphed on to the surface of the PEM, or may be applied on to the porous carbon gas diffusion layer and subsequently attached by hot-pressing on to the PEM. In the latter case, the combined electrode and GDL is termed a gas diffusion electrode. The presence of an ionomeric binder in the electrode is vital to ensure that proton transport from the reactive sites of the electrocatalyst to the membrane interface and vice versa proceeds with minimal resistive losses. In the interests of membrane electrode interfacial stability, it is advisable to use the same ionomeric material in the PEM and electrode. 

Preliminary fuel cell evaluations were performed on the 2,5-PPBl membrane from the PPA process and are shown in Fig. 20. All of the tests were conducted on non-humidified feed gases and performed rehably imder these completely dry conditions. 

While the objective is an application in fuel cells, most of the studies performed on new materials do not include a fuel cell evaluation. Moreover, when some fuel cell tests are presented, they are restricted to a polarization curve to estimate the fuel cell performance in comparison with Nafion and only scarce works concern the long-term stability. The specifications for automotive application are 5000 h of operation at 80°C over 5-10 years and more than 10,000 start-stop cycles (typically 3 cycles per day over 10 years). The latter constraint is probably the most difficult to achieve since Nafion membranes are able to operate for more than 10,000 h under stationary load and temperature conditions, but the fifetime is reduced to a few hundred hours when operating under cycling conditions [ 145]. The membrane lifetime is defined as the duration of fuel cell operation until a total or partial rupture induces gas mixing. It is well known that the membrane stability can be significantly enhanced by increasing the membrane thickness or decreasing the ion content, but this stability would be obtained at the expense of the fuel cell performance, which is not acceptable. 

As a constituent of synthesis gas, hydrogen is a precursor for ammonia, methanol, Oxo alcohols, and hydrocarbons from Fischer Tropsch processes. The direct use of hydrogen as a clean fuel for automobiles and buses is currently being evaluated compared to fuel cell vehicles that use hydrocarbon fuels which are converted through on-board reformers to a hydrogen-rich gas. Direct use of H2 provides greater efficiency and environmental benefits. ... 

Fuel cell technology probably offers a new emerging area for polyheterocyclic polymers as membranes. Fuel cells are interesting in transport applications and are now being evaluated in Chicago in transit buses with a 275-hp engine working with three 13 kW Ballard fuel cell stacks. 

The single cell thus fabricated was placed in a single chamber station as illustrated in Fig. 2. A humidified mixture of methane and oxygen was supplied to the station so that both electrode compartments were exposed to the same composition of methane and oxygen. For the measurement of the cell temperature, a thermocouple (TC) was placed approximately 4 mm away from the cathode site. For the evaluation of the fuel-cell performance, Ft wires and Inconel gauzes were used as the output terminals and electrical collectors, respectively. 

In order to describe the geometrical and structural properties of several anode electrodes of the molten carbonate fuel cell (MCFC), a fractal analysis has been applied. Four kinds of the anode electrodes, such as Ni, Ni-Cr (lOwt.%), Ni-NiaAl (7wt.%), Ni-Cr (5wt.%)-NijAl(5wt.%) were prepared [1,2] and their fractal dimensions were evaluated by nitrogen adsorption (fractal FHH equation) and mercury porosimetry. These methods of fractal analysis and the resulting values are discussed and compared with other characteristic methods and the performances as anode of MCFC. 

Recently, rhodium and ruthenium-based carbon-supported sulfide electrocatalysts were synthesized by different established methods and evaluated as ODP cathodic catalysts in a chlorine-saturated hydrochloric acid environment with respect to both economic and industrial considerations [46]. In particular, patented E-TEK methods as well as a non-aqueous method were used to produce binary RhjcSy and Ru Sy in addition, some of the more popular Mo, Co, Rh, and Redoped RuxSy catalysts for acid electrolyte fuel cell ORR applications were also prepared. The roles of both crystallinity and morphology of the electrocatalysts were investigated. Their activity for ORR was compared to state-of-the-art Pt/C and Rh/C systems. The Rh Sy/C, CojcRuyS /C, and Ru Sy/C materials synthesized by the E-TEK methods exhibited appreciable stability and activity for ORR under these conditions. The Ru-based materials showed good depolarizing behavior. Considering that ruthenium is about seven times less expensive than rhodium, these Ru-based electrocatalysts may prove to be a viable low-cost alternative to Rh Sy systems for the ODC HCl electrolysis industry. 

It would certainly be desirable to evaluate catalyst performance and understand size and stmctural effects directly under the conditions of fuel cell operation. However, determination of kinetic parameters in a single-cell fuel cell is associated with a number of limitations. Let us consider some of them. 

Leng YJ, Chan SH, Khor KA, and Jiang SP. Performance evaluation of anode-supported solid oxide fuel cells with thin-film YSZ electrolyte. Int J Hydrogen Energy 2004 29 1025-1033. 

Tietz F, Dias FJ, Simwonis D, and Stover D. Evaluation of commercial nickel oxide powders for components in solid oxide fuel cells. J Eur Ceram Soc 2000 20 1023-1034. 

Labrincha JA, Li-Jian M, dos Santos MP, Marques FMB, and Frade JR. Evaluation of deposition techniques of cathode materials for solid oxide fuel cells. Mater Res. Bull. 1993 28 101-109. 

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