13:11 25 July 2008/ NewScientist.com news service/ by Colin Barras
A new approach to storing electrical energy can store more energy
than gasoline in the same volume, and could help extend the range of
electric vehicles. But some experts say other approaches are more
practical.
The
biggest technological hurdle facing electric vehicles is their range.
Even the best rechargeable batteries cannot match the density of energy
stored in a fuel tank.
Combining electric power with a combustion engine to make a hybrid electric vehicle sidesteps that problem. But a new take on electrical power storage that is part battery, part chemical fuel cell could ditch gasoline for good.
The new design stores energy more densely than petrol, and was conceived by Stuart Licht of the University of Massachusetts, Boston, and colleagues.
Gasoline beater
Batteries
produce electricity from a closed chemical system that is eventually
exhausted. Fuel cells use a constant supply of fuel, so they are
continually topped up. Licht's cell has features of each.
Its
negative electrode, or anode, is made from vanadium boride, which
serves double-duty as a fuel too. But unlike the flowing fuel of a fuel
cell, the material is held internally, like the anode material of a
battery.
The
vanadium boride reacts with a constant stream of oxygen, as in a fuel
cell, provided by the positive electrode, or cathode. This brings in a
supply of air from outside.
The
cell has a theoretical energy capacity of 27 kilowatt hours per litre,
compared to 9.7 kilowatt hours per litre for gasoline. But both
approaches are limited by practical factors to smaller figures.
Licht
says his new system would likely have a practical energy capacity of
around 5 kilowatt hours per litre. "But that's two-fold higher than the
practical storage capacity of gasoline," he says...
Full article: Fuel battery
