A team of Stanford researchers led by chemistry professor Hongjie Dai has developed an aluminum-ion battery that offers many significant advantages over the conventional lithium-ion batteries currently used in most electronic devices and today’s electric cars. Let’s take a look at what makes the Stanford aluminum-ion battery such an important breakthrough.
Not a fire hazard
The aluminum battery won’t burst into flame the way a lithium battery can. “[L]ithium batteries can go off in an unpredictable manner – in the air, the car or in your pocket,” says professor Dai.
That’s important because in automobiles, a lithium-ion battery needs a heavy shield around it to protect the car from damage if the battery ignites. And because of that shielding, a lithium-ion battery needs its own dedicated cooling system, which adds even more weight and cost. Extra pounds mean automobile manufacturers have to specify larger batteries and larger motors to lug around the increased weight. That raises the cost of the car, which raises its price in the marketplace.
The Stanford aluminum battery can be recharged in far less time than a lithium-ion battery — in as little as one minute in some applications. The implications for laptop computers and cell phones are huge, but the impact on electric and hybrid cars could be even bigger.
One of the biggest drawbacks to electric and hybrid cars today, besides high cost, is the number of hours it takes to recharge a depleted battery. If a driver knew recharging the battery would take no longer than the time it takes to pump a tankful of gas, that would break down one of the biggest remaining barriers to the widespread adoption of such environmentally friendly vehicles.
A typical lithium-ion battery usually lasts for about 1000 discharge cycles before it must be replaced. The Stanford aluminum battery shows no sign of losing performance after 7,500 discharge cycles. Lots of drivers have concerns about having to spend a lot of money to replace the battery in their EV after a few years. That worry could now be a thing of the past. The aluminum-ion battery could actually last longer than the car itself.
Aluminum is abundant and costs less than lithium. That could drive down the cost of batteries and that would be another factor working in favor of electric cars going mainstream sooner rather than later.
Lithium is toxic and must be disposed of with care. Aluminum is non-toxic and can be recycled repeatedly. Billions of small lithium batteries power our assortment of electronic gadgets that we can’t live without. Replacing them with aluminum batteries would rid the environment of hazards from discarded lithium batteries.
Another advantage of the aluminum battery is it is flexible, so it can be shaped and molded to fit a variety of applications that can’t use a lithium battery encased in a hard protective shell.
There is no free lunch, of course. For now, the Stanford aluminum battery can only supply about half the voltage of a lithium battery. “But improving the cathode material could eventually increase the voltage and energy density,” professor Dai says.
“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.”
“Exciting” is an understatement.