Saturday science topic: A new hydrogen fuel cell
Two chemists at the Arizona State University, Don Gervasio and Sonja Tasic, have developed a new hydrogen-based fuel cell they say could achieve more than ten times the energy density of conventional lithium-ion batteries found in notebooks and other portable devices.
Gervasio's solution was to use the alkaline compound borohydride. A 30% solution of borohydride in water actually contains one-third more hydrogen than the same volume of liquid hydrogen. . . . "The difference is that the borohydride is at room temperature, and it's stable, non-toxic and cost-effective," Gervasio says.
The borohydride solution releases its hydrogen as it flows over a catalyst made of ruthenium. The hydrogen passes through a membrane and combines with oxygen in the fuel cell, generating electricity and waste water.
Early versions of the fuel cell reportedly became clogged up with boron oxide, but Gervasio and his team were able to get around this problem using ethylene glycol—antifreeze—to dissolve the boron oxide. The fuel cell now runs on a 15% boronhydride solution and has energy density of 600 watt-hours per liter, which is three times greater than conventional batteries. Gervasio reckons the technology could find its way into laptops and digital camcorders "within five years."