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Alkaline fuel cell membrane delivers promise of affordable fuel cells

A major innovation in the world of fuel cells was published in the German Chemical Engineering Journal Angewandte Chemie. Professor Yushan Yan of UC Riverside and associates have developed an alkaline membrane that they believe will one day enable non-precious metal fuel cell catalysts that are composed of elements such as cobalt, nickel, iron and silver.

These metals cost between $2 and $12 per ounce as compared to platinum that currently trades in the range of $1,200/ounce and peaked at over $2,000/ounce last summer. As this innovation is commercialized it will lead to a massive drop in the cost of goods needed to produce fuel cells. This price reduction will allow fuel cells to have a lower price point per watt than internal combustion engines and batteries. Currently fuel cells are considered to be superior to internal combustion engines and batteries in terms of size, weight, temperature, noise, safety, scalability and carbon footprint. However, cost and durability Fuel cells are currently used to power backup generators, unmanned aerial vehicles (UAV’s), scooters, golf carts, cell phones, laptops, emergency generators and in next generation automobiles like the Honda FCX Clarity.

Despite the many advantages and demonstrated uses of fuel cells, they are expensive because they require platinum and other precious metals as catalysts. The best way to eliminate platinum while maintaining the many benefits is through the use of a high performance hydroxide exchange membrane, equivalent for a alkaline fuel cell. Recently, Dr Yan’s lab has demonstrated a power density of 250 mW/cm2 using an alkaline membrane composed of quaternary phosphonium based polymers. His team expects to improve this in the near future.

By switching from an acidic medium to a basic one, hydroxide (OH-) exchange membrane fuel cells (HEMFCs) have the potential to solve the problems of catalyst cost and durability while achieving high power and energy density. In a basic environment, the cathode oxygen reduction over-potential can be significantly reduced, leading to high fuel cell efficiency, and non-precious metals can be used as catalysts which are also more durable in a basic medium. Further, HEMFCs can offer fuel flexibility using hydrogen, methanol, ethanol, ethylene glycol, and other inexpensive, easily produced and biodegradable fuels because of their low overpotential for hydrocarbon fuel oxidation and reduced fuel crossover. “This is a breakthrough that will make fuel cells so efficient and inexpensive that it will revolutionize energy conversion and storage on a global scale.” said Dr. Yan.

Dr. Yan and UC Riverside have licensed this invention to Full Cycle Energy, a California start-up that is leading the revolution in low-cost high-durability fuel cell technology. Currently Full Cycle is commercializing another of Yan’s inventions, a platinum nanotube fuel cell catalyst (PtNT) that reduces cost by 2/3 and increases durability by a factor of 10. Production of PtNT is currently being scaled up for integration into a range of fuel cell products. According to CEO Andrew Behar, “The only thing stopping fuel cells from replacing fossil fuels and batteries is cost and durability. Dr. Yan’s innovations will enable a world powered by inexpensive, clean and abundant energy.”

by S. C.
21 august 2009, Technical Area > Science News