By Josh Perry, Editor
[email protected]

Researchers at the University of Michigan (Ann Arbor, Mich.) have created a new rechargeable battery design with a ceramic, solid-state electrolyte that could double the output of lithium-ion cells without requiring more space, which could be a breakthrough for cell phones and electric vehicles.

Nathan Taylor, a post-doctoral fellow in mechanical engineering, inspects a piece of lithium metal in the Phoenix Memorial Laboratory building. (Evan Dougherty, Michigan Engineering)

According to an article from the university, the ceramic electrolyte allows engineers to “harness the power of lithium metal batteries without the historic issues of poor durability and short-circuiting. The result is a roadmap to what could be the next generation of rechargeable batteries.”

The move away from potentially flammable liquid electrolytes has been the topic of numerous research papers in the past few years, as public concerns over thermal runaway in cell phone batteries have grown.

Michigan researchers created a ceramic layer that stabilizes the surface of the lithium metal, which prevents dendrites forming that can impair performance over time and also prevents fires. Lithium metal in a solid-state battery has a specific capacity of 3,800 mAh/g, which significantly higher than graphite’s 350 mAh/g. It also has a potential energy density of 1,200 Wh/L, which is double standard lithium-ion cells.

It is also not combustible, as researchers tested it to 1,800°F.

“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 article explained. “U-M 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.”

The researchers were able to charge a car battery in three hours or less and it showed no degradation after repeated charge/discharge cycling for 22 days.

“Bulk solid-state electrolytes enable cells that are a drop-in replacement for current lithium ion batteries and could leverage existing battery manufacturing technology,” the article concluded. “With the material performance verified, the research group has begun producing thin solid electrolyte layers required to meet solid state capacity targets.”

The research will be published at the end of August in Power Sources.