Scientists at UCLA have developed a powerful new imaging method that could help solve one of the biggest problems holding back next-generation batteries.
These batteries, called lithium-metal batteries, could one day last much longer and store twice as much energy as today’s lithium-ion versions—but they don’t hold up well after repeated recharges.
The UCLA team’s new method, called electrified cryogenic electron microscopy, or eCryoEM, allows researchers to watch what happens inside a lithium-metal battery while it’s charging.
For the first time, they can capture these tiny processes in real time and at a scale smaller than the wavelength of light.
The study was published in the journal Science Advances.
The key issue with lithium-metal batteries is that they wear out too quickly—often after fewer than 200 recharges—compared to thousands of cycles in lithium-ion batteries.
A major cause is a chemical reaction between the lithium metal and the liquid electrolyte, which forms a layer of corrosion that interferes with the battery’s performance.
Until now, scientists could only study this corrosion layer before and after charging, not while it was happening. That left a gap in understanding.
To close this gap, the UCLA team designed a super-thin battery that could be frozen mid-charge in liquid nitrogen. By doing this at different points during the charge process, they created a kind of stop-motion animation showing how the corrosion layer forms and grows.
What they found surprised them. Comparing two different types of electrolyte liquids—one high-performing and one low-performing—they expected the better one to slow down corrosion by limiting how quickly electrons pass through the layer.
But the biggest difference turned out to be in the earliest stage of corrosion, when the lithium metal first reacts with the electrolyte. The better electrolyte was simply less reactive, which slowed down the corrosion process right from the start.
This suggests that researchers should focus more on designing electrolytes that are less chemically reactive, rather than only trying to engineer the corrosion layer itself. While this idea isn’t entirely new, the eCryoEM method finally provides solid data to back it up.
Beyond batteries, this new imaging method could have wide-reaching impact. It may help researchers understand other technologies like supercapacitors and carbon capture systems. Even more exciting, the same approach could be used to study brain cells—by freezing them in the middle of electrical activity—to learn more about how they work and how diseases affect them.
With this powerful tool, scientists are opening new windows into both clean energy and biology, one frozen frame at a time.
