Aluminium-ion battery breakthrough promises one-minute charging and batteries that (almost) never die

Stanford University team claims aluminium batteries will outlast lithium-ion - and be much safer, too

Researchers at Stanford University claim that they have devised batteries made from aluminium-ion that can be fully charged in as little as one minute - and which will be safer than conventional lithium-ion batteries currently used in smartphones and laptops.

Aluminium has long been considered an attractive material for use in batteries, mainly because of its low cost, low flammability and high-charge storage capacity, according to the university. However, researchers have unsuccessfully tried for decades to develop a commercially viable aluminium-ion battery - until now.

The claims are made in the journal Nature and the battery technology was developed by a team led by professor Hongjie Dai at the university. The breakthrough, according to the university, was the discovery that graphite could be used with aluminium in the batteries.

An aluminium-ion battery consists of two electrodes: a negatively charged anode made of aluminium 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."

For the experimental battery, the Stanford team placed the aluminium 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 Nature study.

The batteries that professor Dai and his team claim to have developed are also more durable. While a typical lithium-ion battery can last for about 1,000 charging cycles, aluminium batteries developed so far are typically dead within 100. However, the battery developed by Dai can withstand more than 7,500 charging cycles without any loss of capacity.

This could make it suitable for more than just smartphones and laptops, but also for storing renewable energy from solar panels and wind turbines to iron-out their unpredictability. "Another feature of the aluminum battery is flexibility," Gong said. "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."

The batteries are also much more stable compared to conventional lithium-ion batteries. "In our study, we have videos showing that you can drill through the aluminium 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 aluminium battery performance."