Scientists at Stanford University have developed a prototype bendable battery made from aluminum that charges very quickly, is long lasting and offers safety advantages over lithium cells given the materials used are less volatile and do not catch fire if perforated. So, bottom line, aluminum-ion batteries could result in safer consumer electronics in future that also charge faster and can have thinner or even flexible form factors — all of which sounds pretty handy for future generations of wearables.
We’ve seen thin and bendy lithium-ion batteries in research labs before, but aluminum offers cost and safety advantages over lithium — hence researchers’ ongoing interest in the material. And while developing a high performance, commercially viable aluminum-ion battery has proved elusive thus far, the Stanford researchers stumbled on using graphite (a type of carbon) for the cell’s cathode — which they say yields good performance.
Their battery has been able to withstand more than 7,500 charging cycles without any loss of capacity, vs other lab developed aluminum batteries typically lasting around 100 cycles before expiring. “This was the first time an ultra-fast aluminum-ion battery was constructed with stability over thousands of cycles,” the authors write in the journal Nature, where their research has been published.
The ionic liquid electrolyte they’re using for the battery is a salt that’s liquid at room temperature — another safety and environmental advantage for their proto cell — held inside a flexible polymer-coated pouch. Their battery can generate around 2 volts of electricity, which they say is also higher than other researchers have achieved with aluminum. In the video they demo a couple of their prototype batteries being used to charge a smartphone “within a minute”.
Of course it’s early days for the research, with improvements to voltage and energy density required if the tech is to be commercialized. But the researchers seem positive their aluminum-ion battery tech has promise.
“Our battery produces about half the voltage of a typical lithium battery. But improving the cathode material could eventually increase the voltage and energy density. Otherwise, our battery has everything else you’d dream that a battery should have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life. I see this as a new battery in its early days. It’s quite exciting,” Hongjie Dai, a professor of chemistry at Stanford and one of the researchers, told the Stanford Report.
Beyond small electronics devices, one interesting potential use-case mentioned by Dai is for storing renewable energy on the electrical grid. Lithium cells’ durability means they aren’t ideally suited for this application. But aluminum cell’s ability to last for tens of thousands of charges, and their rapid charge and discharge, offers a possible future alternative.