Nov 17 2005
PolyFuel, Inc., a world leader in engineered membranes for fuel cells, announced that it is reprising its real-time shootout between PolyFuel’s hydrocarbon-based fuel cell membrane, and Du Pont’s fluorocarbon-based Nafion® – this time focusing on “passive” direct methanol fuel cells (DMFC). Like last year’s highly revealing contest – which focused on “active” direct methanol fuel cells, PolyFuel is expected to once again demonstrate superior operating performance – in this case, approximately up to 67% more power – under otherwise identical operating conditions. The shootout will occur at the annual Fuel Cell Seminar, being held in Palm Springs, CA.
Fuel cell designs are being readied the world over by the world’s leading battery and consumer electronics manufacturers to replace or augment batteries in increasingly power-hungry mobile electronics devices, and the thin, cellophane-like membrane is the heart of a fuel cell. For portable applications, where high-performance – i.e. long run times – and small size are key considerations, passive fuel cells are preferred, but technically more challenging. Unlike active fuel cells, which may employ small pumps to transfer fuel and water inside the fuel cell and fans to supply air and provide cooling, passive fuel cells depend mainly upon convection for the same purposes, and require higher concentrations of fuel – in this case methanol. This, in turn, places greater performance demands upon the membrane, which must be specifically engineered to withstand such high concentrations.
PolyFuel’s hydrocarbon DMFC membrane was shown last year in an active fuel cell test setup to demonstrate methanol and water crossover advantages over Nafion 117 under identical operating conditions, at Nafion-friendly methanol concentrations of 3%. At this year’s shootout, however, PolyFuel will increase the concentration to 12% – a value increasingly demanded by portable fuel cell designers as a minimum. PolyFuel’s membrane, which has been specifically designed for such high concentrations, routinely produces approximately 67% more power than Nafion at the 12% level. Methanol crossover and membrane swelling – two nagging side effects of high methanol concentrations – are minimal in the PolyFuel membrane. In the Nafion case, the methanol crossover rises to such a high level that it overwhelms the electrochemical reaction, limiting the power in respect to PolyFuel.
Attendees at this important industry seminar will be able to observe these differences for themselves, in real time, in both active – and now passive – designs. Nafion, which has been around for 40 years, is based upon the same fluorocarbon polymer used for Teflon®. PolyFuel’s recently introduced membrane uses a much newer – and to many, more promising technology, based upon a hydrocarbon polymer.
Like last year, the setups will be identical, differing only in the membrane. The passive cells will be operated at 40C, using ambient air, 8 milligrams (mg) total platinum catalyst loading per square centimeter, and SGL carbon gas diffusion layers (GDLs). Fuel concentrations of 3% (1 Molar) and 12% (4 Molar) will be used.
“Since last year’s shootout, we are seeing a significant shift among fuel cell system developers from the older fluorocarbon technology to our hydrocarbon DMFC membrane, as our customers confirm the performance advantages for themselves, in their own labs,” said Jim Balcom, president and CEO of PolyFuel. “The shootout will expose virtually the entire fuel cell community to our performance benefits in the technically more challenging area of passive fuel cells.” Among fuel cell designers, said Balcom, high-performance passive fuel cells are the “brass ring.” “Robustness under high fuel concentrations, fewer moving parts, low weight and small size are the goal, and we believe that we are the only practical way to get there,” he said. “And at an expected 67% performance advantage over Nafion, it’s no contest.”
The market for portable fuel cells is predicted by NanoMarkets LLC to be US$1.1 billion by 2009 and US$2.6 billion by 2012. First commercial shipments are expected in 2006.