Electric car purchases have been on the rise lately, posting an estimated 60 percent growth rate last year. They’re poised for rapid adoption by 2022, when EVs are projected to cost the same as internal combustion cars. However, these estimates all presume the incumbent lithium-ion battery remains the go-to EV power source. So, when researchers this week at the University of Texas at Austin unveiled a new, promising lithium- or sodium-glass battery technology, it threatened to accelerate even rosy projections for battery-powered cars.
“I think we have the possibility of doing what we’ve been trying to do for the last 20 years,” says John Goodenough, coinventor of the now ubiquitous lithium-ion battery and emeritus professor at the Cockrell School of Engineering at the University of Texas, Austin. “That is, to get an electric car that will be competitive in cost and convenience with the internal combustion engine.” Goodenough added that this new battery technology could also store intermittent solar and wind power on the electric grid.
Yet, the world has seen alleged game-changing battery breakthroughs come to naught before. In 2014, for instance, Japanese researchers offered up a cotton-based (!) new battery design that was touted as “energy dense, reliable, safe, and sustainable.” And if the cotton battery is still going to change the world, its promoters could certainly use a new wave of press and media releases, as an Internet search on their technology today produces links that are no more current than 2014-2015 vintage.
So, on whose authority might one claim a glass battery could be any different?
For starters, Donald Sadoway’s. Sadoway, a preeminent battery researcher and MIT materials science and engineering professor, says, “When John Goodenough makes an announcement, I pay attention. He’s tops in the field and really a fantastic scientist. So, his pronouncements are worth listening to.”
Goodenough himself says that when he first coinvented the lithium-ion battery in the 1980s, almost no one in the battery or consumer electronics industries took the innovation seriously. It was only Japanese labs and companies like Sony that first began to explore the world we all today inhabit—with lithium-ions powering nearly every portable device in the marketplace, as well as electric vehicles and even next-generation airliners.
In other words, who better than Goodenough to cocreate the technology that could one day supplant his mighty lithium-ion battery?
The new battery technology uses a form of glass, doped with reactive “alkali” metals like lithium or sodium, as the battery’s electrolyte (the medium between cathode and electrode that ions travel across when the battery charges and discharges). As outlined in a research paper and recent patent filing (of which Goodenough, 94, says more are forthcoming), the lithium- or sodium-doped glass electrolyte offers a new medium for novel battery chemistry and physics.
They find, for instance, that the lithium- or sodium-glass battery has three times the energy storage capacity of a comparable lithium-ion battery. But its electrolyte is neither flammable nor volatile, and it doesn’t appear to build up the spiky “dendrites” that have plagued lithium-ions as they charge and discharge repeatedly and can ultimately short out, causing battery fires. So, if the glass batteries can be scaled up commercially, which remains uncertain in this still-proof-of-concept-phase research, the frightening phenomenon of flaming or exploding laptops, smartphones, or EVs could be a thing of the past.
Moreover, says lithium-glass battery codeveloper Maria Helena Braga, a visiting research fellow at UT Austin and engineering professor at the University of Porto in Portugal, the glass battery charges in “minutes rather than hours.” This, she says, is because the lithium- or sodium-doped glass endows the battery with a far greater capacity to store energy in the electric field. So, the battery can, in this sense, behave a little more like a lightning-fast supercapacitor. (In technical terms, the battery’s glass electrolyte endows it with a higher so-called dielectric constant than the volatile organic liquid electrolyte in a lithium-ion battery.)
Moreover, Braga says, early tests of their technology suggest it’s also capable of perhaps thousands of charge-discharge cycles, and could perform well in both extremely cold and hot weather. (Initial estimates place its operating range between below -20º C and 60º C.) And if they can switch the battery’s ionic messenger atom from lithium to sodium, the researchers could even source the batteries more reliably and sustainably. Rather than turning to controversial mining operations in a few South American countries for lithium, they’d be able to source sodium in essentially limitless supply from the world’s seawater.
Sadoway says he’s eager to learn more about the technology as it continues to be developed. In particular, he’s paying attention not so much to how quickly the battery charges but how well it can retain its energy. “The issue is not can you do something at a high charge rate,” he says. “My big question is about capacity fade and service lifetime.”
But, Sadoway adds, perhaps the chief innovation behind Goodenough and Braga’s technology is the possibility that they’ve solved the flaming and exploding battery problem.
“Addressing the [battery] safety issue is, I think, a giant step forward,” he says. “People have been talking about solid-state electrolytes for 20 years. But I can’t point to a commercial product yet…. If he can give us an electrolyte that is devoid of these flammable, organic solvents, that’s salutary in my opinion.”
If Goodenough, Braga, and collaborators can ramp up their technology, there would clearly be plenty of upsides. Goodenough says the team’s anode and electrolyte are more or less ready for prime time. But they’re still figuring out if and how they can make a cathode that will bring the promise of their technology to the commercial marketplace.
“The next step is to verify that the cathode problem is solved,” Goodenough says. “And when we do [that] we can scale up to large-scale cells. So far, we’ve made jelly-roll cells, and it looks like they’re working fairly well. So I’m fairly optimistic we’ll get there. But the development is going to be with the battery manufacturers. I don’t want to do development. I don’t want to be going into business. I’m 94. I don’t need the money.”