Super battery system may shift balance of powerGovernment researchers develop portable power system that far exceeds best available batteries
By Doug Page
The energy available to small portable devices, compared to today’s batteries, has been substantially increased by a super battery developed by researchers at the Savannah River National Laboratory, near Aiken, S.C.
Among other benefits, the development means that responders may one day have a system that dramatically increases the lifetime of portable devices used at disaster sites.
The Savannah River work is based on the use of alane, or aluminum hydride (AlH3), a lightweight material recently shown to be efficient at storing hydrogen, which has the highest specific energy of any fuel. For instance, portable power equipment manufacturers today are seeking systems that can provide specific energies greater than 1,000 watt-hours per kilogram (Wh/kg).
Currently, the best lithium batteries are only 100 to 200 Wh/kg. Hydrogen, however, is rated at 33,000 Wh/kg, or more than methanol (5,600 Wh/kg), ethanol (7,500 Wh/kg) and gasoline (12,000 Wh/kg) combined.
"Higher specific energy means more energy per weight," said Ted Motyka, Savannah River’s hydrogen program manager. Motyka said the goal of his work is to provide sufficient energy to a system that’s light enough to be carried by a soldier or first responder, or used in unmanned aircraft and other applications where weight is a factor.
The technology combines the alane high-capacity hydrogen storage material along with a portable fuel cell to produce electricity, which powers the portable device the same as a battery.
Alane is not a new material, but in the last few years a handful of scientists around the world, including those at Savannah River, have been investigating how to use it as a hydrogen storage material for fuel cell applications.
"The current status of this work is that a proof-of-concept has been successfully demonstrated," Motyka told Homeland1. "We showed that alane can indeed deliver enough hydrogen to power a portable fuel cell for several hours."
In a bench test, the Motyka team developed a small hydrogen storage vessel containing alane, and demonstrated hydrogen release at delivery rates suitable for powering small commercial fuel cells.
One other significant advantage to alane is that it produces no toxic by-products.
Motyka said that several issues remain, however. "Both material and system cost must be addressed, as well as system design to make sure that when packaged the system demonstrates significant improvement over current commercial battery products," he said.