Ceramic substrate stabilizes lithium batteries

August 16, 2018 // By Julien Happich
Researchers from the University of Michigan have created a solid ceramic-based electrolyte that can stabilize lithium as the metal anode through multiple battery charging/discharging cycles, preventing the formation of short-circuiting dendrites.

The rechargeable battery technology described in the Journal of Power Sources under the paper title "Demonstration of high current densities and extended cycling in the garnet Li 7La3Zr2O12 solid electrolyte" could help metal lithium  make its come-back, doubling the output of today's lithium ion cells.

While current lithium ion batteries max out with a total energy density around 600 watt-hours per liter (Wh/L) at the cell level, solid-state batteries could reach 1,200 Wh/L.

In earlier solid state electrolyte tests, lithium metal grew through the ceramic electrolyte at low charging rates, causing a short circuit, much like that in liquid cells. the researchers solved this problem with chemical and mechanical treatments that provide a pristine surface for lithium to plate evenly, effectively suppressing the formation of dendrites or filaments. Not only does this improve safety, it enables a dramatic improvement in charging rates.

"Up until now, the rates at which you could plate lithium would mean you'd have to charge a lithium metal car battery over 20 to 50 hours (for full power)," explained the team leader Jeff Sakamoto said. "With this breakthrough, we demonstrated we can charge the battery in 3 hours or less.

"We're talking a factor of 10 increase in charging speed compared to previous reports for solid state lithium metal batteries. We're now on par with lithium ion cells in terms of charging rates, but with additional benefits."

The researcher anticipates the new findings will displace lithium ion battery technology. Sakamoto and his team report they cycled the battery for 22 days without observing any degradation. Bulk solid state electrolytes enable cells that are a drop-in replacement for current lithium ion batteries and could leverage existing battery manufacturing technology. With the material performance verified, the research group has begun producing thin solid electrolyte layers required to meet solid state capacity targets.

University of Michigan – www.umich.edu


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