Lithium-ion batteries power everything from our laptops to phones to electric vehicles, but they’re far from perfect. In fact, they were the culprits behind Samsung’s recent exploding Galaxy Note 7 phones.
“The word ‘bomb’ is not out of place here,” says David Pogue, tech columnist for Yahoo Finance and the host of NOVA’s documentary “The Search for the Super Battery.”
As he explains it, lithium-ion batteries are positive and negative electrodes, separated by an electrolyte liquid that happens to be highly flammable. “Lithium-ion is not the best storage device,” Pogue says. “They are explosive, they are expensive … they have a limited amount of hours they can power your phone, and they can only be recharged, let's say, 400 times. So the world really needs something better than this 1991 technology.”
Luckily, he recently scoured research labs all over the country with his documentary team, in search of the “super battery.”
A super battery refers to a single battery that has it all, he explains. “You want it cheap, you want it to last for a long time, you want high-energy density, and you want it to be environmentally friendly — both during its lifetime and after it's done.”
For now, at least, no one battery can do everything we want batteries to do, but Pogue’s travels indicate the research field is booming. “Some of the coolest things we looked at were ice batteries and gravity batteries and flywheel batteries and saltwater batteries and dirt batteries,” he says. “It's just billions of dollars are being poured into this, in research labs all over the world.”
The most promising battery the documentary team came across is being developed by Tufts University Professor Mike Zimmerman, Pogue says. He’s confronted the problem of lithium-ion’s explosive liquids head on — by eliminating the liquids.
“He's made a solid sheet of a special plastic, a special polymer, that lets the ions travel back and forth between the electrodes even better than a liquid electrolyte does,” Pogue says. “And yet, because it's a physical barrier, you can't short out like lithium-ion batteries can. So these are plastic electrode batteries.”
According to Pogue, Zimmerman’s battery can also use lithium metal without risk of short-circuiting. The metal has five times more energy density than the compound we use now, he explains. “But of course, it's five times more explosive as well, so we don't use it. But he can. And already he's getting double the length, the power density of lithium-ion. So think of a car. Now, instead of going 200 miles on a charge, it can go 400 miles on a charge.”
When the documentary team visited Zimmerman’s lab, they turned out to be the first media he’d ever hosted there — the project had been under wraps for several years, Pogue says. “And I said, ‘Why aren’t Samsungs and Apples beating a path to your door?’” Pogue recalls. “He says, ‘You know who was here yesterday? Samsung.’”
Zimmerman had Pogue test the battery in his lab — by slicing pieces of it away with scissors, as it powered a panel of LED lights. “Not only did it not blow up my face, but the light panel stayed on until I cut this thing into a paper doll,” Pogue recalls.
Zimmerman’s startup, Ionic Materials, is working to commercialize the technology. And while solid-electrolyte batteries could someday power our personal electronics, Pogue says there’s another big focus of research: Developing storage systems for our electrical grid.
“Right now, when you turn on your light, that electricity is not waiting in your wires like water waits in your pipes,” he says. “It has to be generated in real time, and that's a problem for solar and wind, which are intermittent sources. So we need a way to capture solar and wind power so that it'll be there when we need it.”
But unlike consumer electronics, the grid doesn’t need lightweight, compact batteries, he says. “They can be saltwater and other chemistries, and really big and ugly and huge because they don't move. But as long as they are environmentally clean, and they store energy and last for many years, that's just what we need.”
And when it comes to designing batteries for the grid, Pogue is excited about flywheels — which store energy in the momentum of fast-spinning rotors. He’s seen them store energy for a minute or so, but a California company called Amber Kinetics has developed one that can store four hours of energy.
“It's a 5,000-lb. steel wheel, spinning at 8500 rpm. There's no friction because it's suspended by a magnet and in a vacuum canister,” Pogue says. California’s Pacific Gas and Electric Company has already ordered 20 megawatts of grid storage using the flywheel, beginning in 2020.
Pogue says the wheel can be “spun up” at night, using cheap electricity — or during the day, using solar power (as he suggests in the documentary). When we need electricity from the flywheel battery, “the motor will reverse and become a generator, and capture that kinetic motion and turn it back into energy,” he explains.
So, while the search for the super battery is technically still on, Pogue is excited about where the field is going. “To be totally honest with you, when NOVA told me they wanted me to host an hourlong show about battery chemistries, I’m like, 'Oh yeah, there's a best-seller right there,” he says, laughing.
The NOVA documentary aired Feb. 1 on PBS. You can watch it for free online, and support David Pogue’s next NOVA special at his Kickstarter. This article is based on an interview that aired on PRI's Science Friday.