Washington: A new inexpensive aluminum battery that could charge cellphones in just one minute has been developed by Stanford scientists.
The new aluminum battery is much safer than existing lithium-ion and alkaline batteries in wide use today and does not catch fire, researchers 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," said Hongjie Dai, a professor of chemistry at Stanford University.
"Our new battery won't catch fire, even if you drill through it," said Dai. Aluminum has long been an attractive material for batteries, mainly because of its low cost, low flammability and high-charge storage capacity, researchers said.
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," Dai said.
"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," said Dai.
The team placed the aluminum anode and graphite cathode, along with an ionic liquid electrolyte, inside a flexible polymer-coated pouch.
"The electrolyte is basically a salt that's liquid at room temperature, so it's very safe," said Stanford graduate student Ming Gong, co-lead author of the study.
Aluminum batteries are safer than conventional lithium-ion batteries used in millions of laptops and cell phones today, Dai added.
Smartphone owners know that it can take hours to charge a lithium-ion battery. But the team reported "unprecedented charging times" of down to one minute with the aluminum prototype.
Aluminum batteries developed at other laboratories usually died after just 100 charge-discharge cycles. But the Stanford battery was able to withstand more than 7,500 cycles without any loss of capacity.
"This was the first time an ultra-fast aluminum-ion battery was constructed with stability over thousands of cycles," researchers said.
"Another feature of the aluminum battery is flexibility. You can bend it and fold it, so it has the potential for use in flexible electronic devices. Aluminum is also a cheaper metal than lithium," Gong said.
The study was published in the the journal Nature.