You owe most, if not all, of your digital life to lithium-ion batteries. They power your smartphone, your laptop—pretty much anything that recharges except your car battery is powered by lithium. And you have three newly minted Nobel laureates to thank for that. John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino shared the Nobel Prize in Chemistry today for their contributions to the invention of the lithium-ion battery. Each man built upon the work the previous had done, progressively making the technology better and better.
“We think of it as cellphones or hybrid electric vehicles, but it also has an effect for people who don’t have access to electricity,” says Bonnie Charpentier, President of the American Chemical Society. “I just came back from a trip to Botswana where I was out in the bush with no modern conveniences, but our guide had a cellphone and a solar panel.”
But despite how ubiquitous lithium-ion batteries are, few of us have any real sense of why they work so well. Nerd out with us for a few minutes here:
Batteries are pretty simple at their core. They’ve got two charges ends, called electrodes, which are separated so they can’t touch directly. Electrons move from the negatively charged side to the positive one—that movement is what produces power. You can make a battery out of many things (including, as you probably learned back in a school, a potato) but to make a really effective one you need certain specifications. You’d like it to have plenty of electrons to give up, for one, and ideally it’ll be lightweight as well—having 12 hours of battery life on a phone isn’t worth much if that phone weighs five pounds. Lithium absolutely loves giving up its electrons, and as one of the lightest metals, you can pack it into a small container to make it very energy-dense. Plus, you can recharge it.
M. Stanley Whittingham of Binghampton University in New York discovered a way to make a battery with lithium at the positively charged end and titanium sulfide at the other, but there was a problem with his creation. When he recharged the battery, the lithium metal didn’t deposit in an even sheet across the electrode. Instead, it accumulated in little spikes called dendrites, and when those dendrites grew large enough to pierce the separating material and reach the electrode on the opposite side, the battery short-circuited and could potentially catch fire.
The solution, it turned out, would be to not use lithium metal, but rather to use lithium ions sandwiched between layers of other metals. Essentially, the ions can bind to spots inside the crystalline structure of some metals, stashing them in a neat configuration. The lithium ions move from the positive electrode to the negative to discharge power, then back again to recharge their potential.
But it turns out some materials stash lithium ions better than others. It was John B. Goodenough of The University of Texas at Austin who figured out a new, much better material: cobalt oxide. His battery had twice the voltage of Whittingham’s.
That advance made the positive electrode much more efficient, but there were still improvements to be made on the negative end. Akira Yoshino of Meijo University in Japan took the battery through this final step. He discovered that petroleum coke, a carbon-containing byproduct from the oil industry, worked phenomenally well as a negative electrode, and the resulting battery was much safer than previous iterations. Lithium is an incredibly reactive element, so early batteries made with it could catch fire or explode under strain. Yoshino’s could get hammered by a giant piece of iron without anything terrible happening, which made it appropriate for use in consumer goods. (Can you imagine if your phone ran the risk of exploding every time you dropped it?)
In 1991, the first lithium-ion batteries went into gadgets in Japan, and they’ve remained largely unchanged since. Most positive electrodes are now iron phosphate rather than cobalt oxide, to help make them more environmentally friendly, but the negative electrodes are still carbon-based. Researchers around the globe are constantly searching for new, better materials to make even more energy-dense batteries, but so far lithium is the clear leader.
It’s rare—and lovely—to see a success story come out of such a clear line of successive improvements by researchers building on each other’s work. The Nobel Prize is often criticized for perpetuating the myth of lone geniuses making scientific breakthroughs, when the reality is that most important research is the result of many years of trial and error—and many cooks in the kitchen. The prize is still far from representative of the fields it claims to recognize, especially when it comes to rewarding the work of people of color and women. But at least this year, the committee is in some small way highlighting the fact that science is iterative. “It shows the power of collaboration across generations, and across industry and academia,” says Charpentier. “The devil is always in the detail, and the work and patience and insight of these three prize winners is remarkable.”