Few recent inventions have proven their worth more than the humble lithium-ion battery. It's been only 30 years since they first left the lab, but they're what power smartphones in the world's palms and put electric cars on the road. They'll only become more important as critical components of renewable energy grids.

Since the early 1990s, these batteries' prices have fallen more than thirtyfold, even as they've grown ever more powerful. But they aren't perfect. For one, they struggle in the deep cold. At temperatures that wouldn't be unfamiliar to anyone who experiences particularly harsh winters, these batteries don't hold their charge—or deliver it.

But scientists are trying to make hardier batteries. In a paper published in the journal ACS Central Science on June 8, chemical engineers from several universities in China have worked together to build a better battery that holds up as low as minus 31°F.

From past studies, scientists knew that most lithium-ion batteries start flatlining at about minus 4°F. Below this point, they don't hold as much charge, and they aren't as good as transferring it—meaning that it's harder to use them for power. And the colder they go, the worse they perform.

For most of the world, subzero temperatures aren't a problem. But if you live in, say, the American Midwest, your electric car might have less range in January than you might like. And if you've ever been caught outside in the frozen winter, you might have noticed that your phone's battery tends to drain more quickly.