Rechargeable battery tech developed that doubles output of lithium-ion cells

Development could pave the way for the next generation of rechargeable batteries

Researchers at the University of Michigan have developed a rechargeable battery technology that could double the output of modern-day lithium-ion cells, paving the way for "the next generation of rechargeable batteries".

The new battery is said to "drastically" extend electric vehicle ranges and time between cell phone charges, without taking up any added space.

The technology was supposedly created by using a ceramic, solid-state electrolyte that the engineers say can harness the power of lithium metal batteries without the historic issues of poor durability and short-circuiting.

"This could be a game-changer; a paradigm shift in how a battery operates," said Jeff Sakamoto, the institution's associate professor of mechanical engineering, who led the work.

The engineers created the battery via a ceramic layer that stabilises the surface, keeping dendrites from forming and preventing fires. This allows batteries to harness the benefits of lithium metal, such as energy density and high-conductivity, without the dangers of fires or degradation over time.

"What we've come up with is a different approach--physically stabilizing the lithium metal surface with a ceramic," Sakamoto added. "It's not combustible. We make it at over 1,800 degrees Fahrenheit in air. And there's no liquid, which is what typically fuels the battery fires you see.

"You get rid of that fuel, you get rid of the combustion."

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.

But the researchers solved this problem with chemical and mechanical treatments that provided a more pristine surface for lithium to plate evenly and effectively suppress the formation of dendrites or filaments.

Sakamoto explained that this not only does this improve safety, but 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," 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."

That charge/recharge process is what inevitably leads to the eventual death of a lithium ion battery. Repeatedly exchanging ions between the cathode and anode produces visible degradation right out of the box.

In testing the ceramic electrolyte, however, no visible degradation is observed after long term cycling, said Nathan Taylor, a post-doctoral fellow in mechanical engineering at the University.

"We did the same test for 22 days," he said. "The battery was just the same at the start as it was at the end. We didn't see any degradation."

With the material performance verified, the research group has now begun producing thin solid electrolyte layers required to meet solid state capacity targets.

The full research paper will be published in the next issue of the Journal of Power Sources.