In a surprising electrifying twist, researchers have found that charging lithium-ion batteries at high currents during their very first charge significantly improves their lifespan. This new method, developed by scientists at the SLAC-Stanford Battery Center, cuts the initial charging time down from 10 hours to just 20 minutes while boosting battery life by a whopping 50%.
A Counterintuitive Strategy for Better Batteries
Lithium-ion batteries power everything from smartphones to electric vehicles. Their performance hinges on a lot of things but one critical step is often overlooked: the first charge. This initial cycle, known as the “formation charge,” sets the stage for how well a battery will perform and how long it will last, much like the initial steps in a long marathon.
This initial charging process is not merely a matter of topping off the battery. It serves as a foundational event that determines the long-term health and efficiency of a lithium-ion battery.
“Formation is the final step in the manufacturing process,” said Xiao Cui, the lead researcher for the battery informatics team, “so if it fails, all the value and effort invested in the battery up to that point are wasted.”
Traditionally, manufacturers have used low currents for this step, believing it would create a stable, protective layer within the battery. But this slow method is both time-consuming and costly.
Now, a study published in the journal Joule suggests a radical shift in approach. The research team, led by Professor Will Chueh at SLAC/Stanford and in collaboration with the Toyota Research Institute (TRI), tested 186 Li-ion batteries cycled across 62 formation protocols and found that charging new batteries at high currents could be the key to extending their life.
Using machine learning, the team pinpointed two crucial factors — temperature and charging current — that influence the formation of this protective layer on the battery anode’s surface, known as the solid electrolyte interphase (SEI). Surprisingly, charging at high currents didn’t degrade the battery. Instead, it improved its longevity.
Why the First Charge Matters
During the first charge of a lithium-ion battery, some of the lithium becomes part of the SEI, a “squishy layer” that protects the battery’s negative electrode. This layer is vital for preventing side reactions that could degrade the battery over time. Oddly enough, losing a significant portion of lithium during the first charge actually helps in the long run. It’s like a down payment that yields significant returns.
Researchers discovered that charging at higher currents speeds up this initial process, resulting in a better-formed SEI and a more efficient battery. They found that this method deactivates more lithium ions up front — about 30% compared to just 9% with traditional methods. While this might seem counterintuitive, the extra “headspace” created allows the battery to operate more effectively, akin to scooping some water out of a full bucket to prevent spillage.
“Battery manufacturing is extremely capital, energy, and time intensive,” said Steven Torrisi, a senior research scientist at TRI. “The results of this study show a generalizable approach for optimizing this crucial step in battery manufacturing.”
The findings have significant implications. Faster and more efficient battery production could impact a range of technologies that rely on lithium-ion batteries, from consumer electronics to renewable energy storage — but perhaps the most significant boost would be for electric vehicles, where the battery represents about 30% of the vehicle’s entire cost. The study’s insights into the early stages of battery life may lead to new methods and materials for manufacturing more durable and efficient batteries.
While the technique still requires further testing and refinement, it’s not often that you get to hear about such a high-value innovation that does so much at such low cost. As the demand for efficient, long-lasting batteries continues to grow, this new method could become a cornerstone of future battery manufacturing practices, potentially reshaping the landscape of energy storage solutions.
