Electric Cars: Quickly Recharge Your Lithium-ion Batteries

Maybe the most frustrating constraint of having an electric car is how long it takes to completely charge the battery. For example, a Tesla car needs approximately 30 minutes to charge it to 75% capacity using the most efficacious charging station.

According to Researchers, the laws of physics restricted how fast you could safely recharge a battery. However, a new study by Tao Gao, assistant professor of chemical engineering at the University of Utah has opened the door to designing a battery that can be recharged in just a fraction of the time.

Gao’s analysis was revealed in a new document published in the scientific journal Joule. The research was led by Gao under the direction of MIT chemical engineering professor Martin Z. Bazant when he was a postdoctoral researcher at the Massachusetts Institute of Technology. Gao is now conducting that study at the University of Utah where he is further enhancing the lithium-ion batteries capable of fast charging.

“This understanding set-up the groundwork for the prospective engineering work required to approach this challenge. Now we know in which direction we have to work. We have clear concepts of what needs to be done.” says Gao. 

Lithium-ion batteries for electric vehicles and portable electronics have become a popular choice because of their long life, high energy density, and low weight. Additionally, they are used in portable electric appliances, solar energy storage, and laptop computers.  

But how fast a lithium-ion battery can recharge is hindered by a reaction known as “lithium plating,” a side process that occurs when lithium ions are inserted into graphite particles too fast. Gao relates the method of a lithium-ion battery to a ping pong ball being hit back and forth on a table. During the charging process, the ball, or lithium-ion, moves from the positive electrode to the negative electrode. The charging frequency is similar to how fast the ball travels. 

According to Gao, Lithium plating happens when the lithium-ion moves quickly and the graphite particles in the battery fail to grab it. While charging, this can be dangerous and cause the battery to catch fire or blast. It limits how quickly batteries can be recharged. Further, it also can severely deteriorate the battery, narrowing its life.

Gao’s discovery shows the essential physics that directs the lithium plating phenomena in graphite particles through battery charging and allows the prediction of lithium plating in the process of a battery.

“We composed an analysis that can reflect what happens to the negative electrode during charging. We can see the material in the negative electrode — the graphite particle — — and we can see results when the battery is charging in real-time,” he says. “Now we know the physics. This gives us the way to discuss this restriction and enhance battery charging performance.”

Gao thinks that with this new knowledge, modern technologies could build a car battery that could be completely charged five times quicker than normal, or in just over 15 minutes, without the risk of jeopardy or deteriorating too quickly, he says. Smartphones, which generally take about two hours with the fastest charger, could also be fully charged in just 10 minutes, he says.

Now that Gao and his associates have a more solid grasp of the science behind lithium-ion charging, he believes we could see electric cars with better batteries in five to seven years and on smartphones in the next three to five years.

Journal Reference:

Tao Gao, Dimitrios Fraggedakis, Yu Han, Supratim Das, Che-Ning Yeh, William C. Chueh, Tingtao Zhou, Ju Li, Martin Z. Bazant, and Shengming Xu. The interplay of Lithium Intercalation and Plating on a Single Graphite ParticleJoule, 2021; 5 (2): 393 DOI: 10.1016/j.joule.2020.12.020

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