Fuel cell systems application materials

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. 

The PEMFC is technically in quite an advanced status. Fuel cell systems for both transport as well as stationary applications exist in a wide variety and are being operated in demonstration programs under practical conditions [57]. For large-scale market introduction, cost has to be reduced significantly, and durability must be improved. Both items cannot be solved by clever engineering only -new materials are also required. 

In another report, James and Kalinoski [4] performed an estimation of the costs for a direct hydrogen fuel cell system used in automotive applications. The assumed system consisted of an 80 kW system with four fuel cell stacks, each with 93 active cells this represents around 400 MEAs (i.e., 800 DLs) per system. The study was performed assuming that the DL material used for both the anode and cathode sides would be carbon fiber paper with an MPL. In fact, the cost estimate was based on SGL Carbon prices for its DLs with an approximate CEP value of around US 12 m for 500,000 systems per year. Based on this report, the overall value of the DLs (with MPL) is around US 42.98 per kilowatt (for current technology and 1,000 systems per year) and 3.27 per kilowatt (for 2015 technology and 500,000 systems per year). Figure 4.2 shows the cost component distribution for this 80 kW fuel cell system. In conclusion, the diffusion layer materials used for fuel cells not only have to comply with all the technical requirements that different fuel cell systems require, but also have to be cost effective. 

S. Voss, H. Kollmann, and W. Kollmann. New innovative materials for advanced electrochemical applications in battery and fuel cell systems. Journal of Power Sources 127 (2004) 93-97. 

There is increased interest in the use of Ru-based systems as catalysts for oxygen reduction in acidic media, because these systems have potential applications in practicable direct methanol fuel cell systems. The thermolysis of Ru3(CO)i2 has been studied to tailor the preparation of such materials [123-125]. The decarbon-ylation of carbon-supported catalysts prepared from Ru3(CO)i2 and W(CO)6, Mo(CO)is or Rh(CO)is in the presence of selenium has allowed the preparation of catalysts with enhanced activity towards oxygen reduction, when compared with the monometallic ruthenium-based catalyst [126],... 

The critical technology development areas are advanced materials, manufacturing techniques, and other advancements that will lower costs, increase durability, and improve reliability and performance for all fuel cell systems and applications. These activities need to address not only core fuel cell stack issues but also balance of plant (BOP) subsystems such as fuel processors hydrogen production, delivery, and storage power electronics sensors and controls air handling equipment and heat exchangers. Research and development areas include ... 

Many potential applications are under study. Miniature chemical reactors could be used for portable applications in which they provide advantages of rapid startup and shutdown and of increased safety (intensification by requiring only small quantities of hazardous materials). The development of chip-scale chemical and biological analysis systems has the potential to reduce the time and cost associated with conventional laboratory methods. These devices could be used as portable analysis systems for detection of hazardous chemicals in air and water. There is considerable interest in using a microreactor to provide in situ production of hydrogen for small-scale fuel-cell power applications by conducting a reformation reaction from some liquid hydrocarbon raw material (e.g., methanol). 

The price of the fuel cell stack is determined by the cost of the materials and the production technology. These costs are strongly determined by the number of units produced. For various components a strong decrease in the price can be expected as the demand increases. As a consequence, reliable cost estimations are difficult. However, the material expenses and some estimates of production costs can be compared with the actual market prices of the competing technologies, namely primary batteries, rechargeable batteries and the internal combustion engine. The comparison shows that fuel cell systems are still too expensive for most applications and a reduction of the cost by a factor of 10-50 is necessary to achieve competitiveness. 

Small locomotives for material transportation in mines have been built up in the last years. The need for emission-free transport and the necessity to reduce the electric power consumption for the tunnel ventilation have generated quite some demonstration projects. In those projects it was shown that the application of fuel cell systems in small trains can offer a promising approach. 

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