Aluminum ready to take over for lithium.

• Position: Batteries

The first high-performance aluminum battery that is fast-charging, long-lasting, and inexpensive has been invented by scientists at Stanford (Calif.) University. Researchers say the new technology offers a safe alternative to many commercial batteries in wide use today.

"We have developed a rechargeable aluminum battery that may replace existing storage devices, such as alkaline batteries, which are bad for the environment, and lithium-ion batteries, which occasionally burst into flames," says Hongjie Dai, professor of chemistry.

Aluminum long has been an attractive material for batteries, mainly because of its low cost, low flammability, and high-charge storage capacity. For decades, researchers have tried unsuccessfully to develop a commercially viable aluminum-ion battery. A key challenge has been finding materials capable of producing sufficient voltage after repeated cycles of charging and discharging.

An aluminum-ion battery consists of two electrodes: a negatively charged anode made of aluminum and a positively charged cathode. "People have tried different kinds of materials for the cathode," explains Dai. "We accidentally discovered that a simple solution is to use graphite, which is basically carbon. In our study, we identified a few types of graphite material that give us very good performance."

Aluminum batteries are safer than conventional lithium-ion batteries used in millions of laptops and cell phones today, Dai adds. "Lithium-ion batteries can be a fire hazard," he stresses. As an...