Anodes are structures inside batteries storing ions, which in turn are like building blocks of electricity. Prelithiation is a manufacturing process that adds lithium to lithium batteries before they undergo their first charge. Scientists at Rice University’s George R Brown School of Engineering have developed a method for priming battery anodes, that improves lithium battery performance. We investigate because this could be significant.
Rationale Behind Priming Battery Anodes
Chemical and biomolecular engineer Sibani Lisa Biswal and her team were able to improve battery life by up to 44%. And then, in a second stream ‘significantly improved’ energy density by substituting silicon for graphite. Sure, this was under laboratory conditions but read on.
“Silicon is one of those materials that has the capability to really improve the energy density for the anode side of lithium-ion batteries,” Biswal explains. “That’s why there’s currently this push in battery science to replace graphite anodes with silicon ones.” However, she still had one more lock to unpick.
The Challenge of the Solid-Electrolyte Interphase
Using silicon at the anode continues to create challenges for battery scientists. And that’s because it forms a solid layer that Interesting Engineering explains actually consumes lithium.
This phenomenon can irreversibly degrade battery performance. Moreover, this layer can become unstable as the anode expands, and contracts during battery recycling. Therefore, Biswal and her team had to find a way to keep the layer stable. They found their answer in a process named prelithiation.
Priming Battery Anodes Through Prelithiation
The team developed a method to moderate the loss of lithium to the solid interphase layer. This improved its stability, so fewer lithium ions were lost. “Prelithiation is a strategy designed to compensate for the lithium loss that typically occurs with silicon,” Biswal explains.
“You can think of it in terms of priming a surface like when you’re painting a wall, and you need to first apply an undercoat to make sure your paint sticks. Prelithiation allows us to ‘prime’ the anodes, so batteries can have a much more stable, longer cycle life.”
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