Bendable New Battery Can Charge a Smartphone in One Minute

Aluminium battery developed at Stanford University
Stanford scientists have invented a flexible, high-performance aluminum battery that charges in about 1 minute. Mark Shwartz

Scientists in the U.S. say they have developed an aluminium battery that can charge a smartphone in as little as a minute.

The battery, which is so flexible it can be folded, could replace alkaline and lithium-ion batteries that are used by millions of people every day according to the Stanford University researchers who developed the new device.

Wired magazine reports that the battery can be charged and recharged thousands of times, and is better for the environment than current widely-used batteries because of its durability.

Hongjie Dai - a professor of chemistry at Stanford and one of the authors of a paper on the battery published in the journal Nature - said: "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."

One prototype charged a smartphone in just one minute, which according to the researchers was an "unprecedented" charging time.

The team claim the batteries are also safer than lithium-ion batteries, which are currently used in millions of electronics such as smartphones and laptops, and can be a fire hazard.The Economist reports that in 2006 millions of battery packs made by Sony had to be replaced after hundreds of them caught fire.

"In our study, we have videos showing that you can drill through the aluminum battery pouch, and it will continue working for a while longer without catching fire," Dai said. "But lithium batteries can go off in an unpredictable manner - in the air, the car or in your pocket. Besides safety, we have achieved major breakthroughs in aluminum battery performance."

Aluminium has a high charge storage capacity, is inexpensive and has a low flammability - all characteristics that make it an ideal material to create effective, cheap and safe batteries. However the team say researchers have previously struggled to develop an aluminium battery that creates enough voltage after repeated charging and discharging.

The authors say that while previous aluminium batteries had died after around 100 charge and discharge cycles during testing at other laboratories, theirs lasted 7,500 without any loss of capacity. They also note that a lithium-ion battery usually lasts around 1,000 cycles.

The battery consists of two electrodes - which conduct electricity - held along with liquid electrolyte inside a coated pouch. The secret to the battery, according to the authors, was the materials used in the cathode - the positively charged electrode.

Professor Dai explained: "People have tried different kinds of materials for the cathode. 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."

The battery stores around half as much voltage as a lithium-ion say the researchers, and so more work is needed to match this energy capacity. The BBC report that the prototype is still several years away from commercial development.