A study published in Nature Materials has been conducted to explain why lithium-ion batteries degrade over time and has recommended that manufacturers rethink design to boost efficiency and longevity.
Researchers at Stanford University, the University of Bath (pictured) and MIT used the Slac National Accelerator Lab at Stanford to monitor the movement of ionic lithium through batteries.
The study charted how power flowed between the negatively charged electrode, the positively charged one and a separator in between, creating areas of high and low energy that lithium ions passed through.
And they said they found the commonly held belief of how a lithium-ion battery works was incorrect.
One of the issues could be that understanding of the movements of the lithium compounds inside batteries is poorly understood, especially because looking at the ions at the nanoscale has not been possible until recently.
Instead of charged particles flowing in a single, uniform direction inside a battery, they move back and forth in random patterns.
Dr William Chueh, a materials science specialist at Stanford, said lithium plotted a messy course, leading to areas where it created a hot spot in the battery. This damages the battery, reducing its storage capacity, given how harmful heat is.
The team said the study could be used to create batteries that lasted longer and held their charge without damaging a battery’s lifespan.
“We used very powerful X-rays from an accelerator, and we’re using these X-rays to look into these individual nanoparticles,” Chueh told the media. “Our original expectation was that lithium moves in certain directions only. We actually saw lithium move in the direction it’s not supposed to move.”
Chueh said previous theories did not account for how the liquid interacted with the solid.
The researchers said the study could have applications for the mass production of electric vehicles and improve the lifespan of billions of gadgets.
They believe they will be able to fix the flaw in battery design by altering the transport pathway and allowing more durable batteries to be designed.
Chueh said: “Previous models don’t really explain how the liquid interacts with the solid. Kind of like in space, we think about how the particle behaves in a vacuum. But a battery doesn’t operate in a vacuum—it operates in a liquid.”
Bath. Picture credit: Wikimedia