Small Fuel Cells 2007

Miami, Fl, USA March 7-9, 2007

by George H. Miley University of Illinois at Urbana-Champaign Urbana, Illinois email: ghmiley@uiuc.edu

This was the 9th international conference in a very successful series on small fuel cells organized and coordinated by The Knowledge Foundation of Brookline, Massachusetts. Held at the Marriott Miami Hotel in Miami, Florida, Small Fuel Cells 2007 featured 27 talks during the main conference program and a half-day pre-conference workshop. Ample time was also provided for individual discussions enhanced by a well-attended company exhibit area and poster displays prepared by individual researchers.

Pre-Conference Workshop

The pre-conference workshop focused on durability. In his welcome to the workshop attendees, Dr. Serge Pan of The Knowledge Foundation stated that the organizers have felt the need to address small and portable fuel cell degradation and durability issues on the materials, the components and the systems level, as a variety of opinions still exist regarding the importance and ways to approach such issues. The workshop was opened by the chairperson, Dr. Michael Stelter of Fraunhofer IKTS in Germany.

Detlef Stolten of the Institute for Materials & Energy Process Engineering, discussed “A 2kW DMFC Development for Light Traction.” The Jülich Research Center has been persuading development of direct methanol fuel cells (DMFC) for power applications. In 2006 it demonstrated a 2kW system with a proven lifetime of more than 500 hours under dynamic operating conditions. The effort is now concentrating on production technology, degradation prevention and quality control procedures.

Yu Seung Kim of Los Alamos National Laboratory presented a paper co-authored with Bryan Pivovar on “Membrane-Electrode Interfacial Degradation in Direct Methanol Fuel Cells: Origin, Diagnosis and Solutions.” They explained how interfacial incompatibility between a polymer electrolyte membrane and the Nafion®-bonded catalyst layer can cause a significant performance loss in DMFC. The origin, diagnosis and solutions for interfacial problems were reviewed, and membrane-electrode assemblies possibly using low permeable alternative membranes were described.

Hyuk Chang of Samsung Advanced Institute of Technology (SAIT), Samsung, Korea, spoke on “Durability and Stability Issues on Mobile DMFC: Analysis & Technical Solution.” In addition to a continued effort to increase power performance of mobile DMFCs, increased attention is now being given to durability and stability issues. Examination of catalysis behavior on the atomic scale shows redeposition of decomposed anode catalyst atoms at the cathode. This phenomena is associated with an intermixture of defective nanocrystalline and amorphous structure. Improvements of the structure are under study. At the same time, a full passive fuel delivery mechanism has been designed along with a stability control system.

Professor George H. Miley of the University of Illinois Urbana-Champaign described “Water Management and MEA Issues Affecting Durability of Direct Borohydride Fuel Cells.” He concentrated on run-time issues for this unique liquid fuel cell. Water recirculation is essential to maintain the solubility of theNaBH4 fuel and the reaction product NaBO2, and avoid clogging of the MEA due to precipitation of either species. In addition, the design of the diffusion layer and the catalyst deposition technique are crucial to prevent small pore holdup or erosion over long run-times. Plasma depositions to improve catalysis deposition on the diffusion layer filters are under study.

Following the talks, a panel discussion , moderated by Emory S. De Castro of E-TEK/PEMEAS Fuel Cell Technologies, addressed “Degradation / Durability Studies and Validation for Micro- and Small Fuel Cells: ‘Should Do’ or ‘Must Do.’” The panelists were Philip Cox of PolyFuel Inc., Jerry Hallmark of Motorola Labs, George Miley of the University of Illinois, Xiaoming Ren of Acta S.p.A, and Detlef Stolten of Research Center Jülich. The gap between what has been achieved for lifetime in small fuel cells and what is needed was discussed. There was general agreement that the gap is closing, but more “field” data is essential. Some expressed the opinion that small fuel cells are closer to commercial goals for durability than are larger cells being developed for automobile use.

The use of higher precious metal (PM) loadings to improve performance/lifetime requirements was noted as an approach under study by some developers, while others are attempting to find alternate catalysts that allow lower loading to reduce cost. Both approaches offer advantages and disadvantages. While progress with catalysis durability is advancing, methods to insure PM recovery poses another aspect of the problem that deserves more attention. Ways to promote consumer recycling must be found. Anode lifetime considerations were also discussed. Improvements are expected through a combination of new materials (e.g., better alloys) and improved engineering methodology. Management of “start-stop” cycles remains a serious challenge since uncontrolled cycling can adversely affect anode lifetime. Down time in particular can promote degradation of components. The search for new anode catalysts to reduce cost and add lifetime was discussed. Some hope was expressed that emerging computational methods for catalyst design will accelerate this search. There was some debate about whether using micro-reformers to produce hydrogen and thus decrease the PM loading while maintaining the power level is offset by increased system complexity, hence higher cost.

In conclusion, the panel generally agreed that progress in lifetime and durability research is bringing fuel cells closer to commercialization. Still, increased “field” experience is essential. This must be combined with research to identify limiting features where significant improvements are possible. A number of questions from the audience were fielded by the panel, showing an intense interest in this topic. This very lively workshop was closed with thanks from Dr. Pan of The Knowledge Foundation.

DoE Fuel Cell and Hydrogen Program

The main conference opened with an invited overview of the Department of Energy fuel cell and hydrogen program. Tim Armstrong of the Oak Ridge National Laboratory represented the DoE in an opening address titled: “The Department of Energy Polymer Electrolyte Membrane Fuel Cell Research and Development Activities.” A major goal of the DoE program is to develop polymer electrolyte membrane (PEM) fuel cells to replace internal combustion engines in light-duty vehicles. In addition, the program supports some work on fuel cells for stationary power, portable power and auxiliary power applications as a way to gain earlier market experience, thus establishing an early fuel cell manufacturing base. DoE’s current technical focus in these areas is on developing materials and components to reduce fuel cell system cost and extend durability.

From System Design and Integration Toward Application and Commercialization

The first session at the conference was chaired by Dr. Deltef Stelter who provided some initial background.

Andrew P. Wallace of Jadoo Power described “Challenges and Opportunities in Deploying Commercial Fuel Cell Systems.” Consumer field data detailing practical impacts of fuel cell system deployment was presented. Jadoo systems have logged over 100,000 hours with over 75,000 start and stops while operated by consumers. Critical design features used to satisfy start/stop reliability and duty cycles include catalyst selection, anode humidification, and open cathode architecture.

Dominique Kluyskens of Angstrom Power Inc. talked about “Infrastructure Options for Micro Hydrogen Systems.” Micro fuel cell systems for portable power use refueling through the use of disposable fuel cartridges. This requires the development of a wide network for cartridge distribution, user adoption of a “primary” cartridge model and consideration of disposal and recycling of cartridges. Infrastructure must be developed while behavioral and environmental hurdles must be overcome. Micro hydrogen systems offer advantages from these points of view by providing a means of incrementally deploying systems and thus leverage off of existing infrastructure. One example is the fast refueling made possible using hydrogen or hydroid kiosks. Angstrom envisions refueling in minutes compared to 45 minutes for batteries.

Ronald J. Kelley of Gecko Energy Technologies Inc. gave a paper entitled “Enabling New Product Designs for Emerging Markets with Fuel Cells.” Fuel cell systems can enable applications that are not economical with conventional battery packs. To do this, fuel cells must take advantage of the unique large charge capability and compact form factors. Opportunities include emerging markets of sensing, wireless networking, remote monitoring, and more. As an example, 31x14x3.7cm Gecko hydrogen battery weighting 2kg can replace a 26 Li D-cell package of 49x14x3.7cm, weighing 2.6kg for powering a 3W wireless sensor. The cell estimated cost is $100 vs. $260 for the battery pack.

Jerry Hallmark of Motorola Labs described “Fuel Cells for Portable Communications.” Motorola is evaluating several fuel cell technologies to possibly exploit the need for extended operation for “remote” portable communications that lack the ability to recharge batteries from the grid. Various system configurations were noted, including external power sources for the charger, hybrid fuel cell/batteries and direct fuel cell power. Some initial opportunities for early introduction of small fuel cells focus on “remote” applications such as first responder, homeland security installations, and military (e.g., soldier power). Motorola is also working on reformed methanol fuel cells using single wall carbon nanotube technology under a National Institute of Standards ATP agreement with BASF and Johnson Matthey.

Yasuhiro Goto of the Advanced Functional Materials Laboratory, Corporate R&D Center, Toshiba Corp., spoke on “Development of DMFC for Mobile Applications at Toshiba.” Flash memory, mobile phones and notebook PCs were described. The audio player with flash memory offers 35 hours play time per fuel cartridge. The phone unit has 2.5 times higher capacity than a normal lithium battery. One fuel cartridge gives ten hours computer time via a docking station. Cartridge exchange is conventionally done while the computer is running. Technical issues still remaining for commercialization include electrode and catalyst activity improvement with lower air rates, membrane barrier strategy and stack integration.

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