EV Batteries Just Keep Getting Better & Better

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The sun is slowly setting on the Age of the Gasmobile, and taxpayers all throughout the US can give themselves a group hug for that. The US Department of Energy has been pumping millions of R&D dollars into new technologies that are making EV batteries charge faster and last longer, while also improving safety. In the latest development, Energy Department scientists are zeroing in on a critical component that could double the energy density of today’s lithium-ion EV batteries.

Your Tax Dollars At Work: Better EV Batteries

The new breakthrough comes under the umbrella of the Energy Department’s Battery500 Consortium, a sprawling Obama-era, public-private energy storage initiative spearheaded by the Energy Department’s Pacific Northwest National Laboratory.

The consortium launched in 2016 with a $50 million, five-year mission to improve the performance and reduce the cost of EV batteries, which topped $500 per kilowatt-hour in 2012. The primary focus is lithium-metal technology, in which lithium replaces the graphite that is commonly used to engineer EV batteries. Lithium-metal batteries also deploy a solid state electrolyte instead of the conventional liquid formula.

“The Battery500 Consortium aims to triple the specific energy (to 500 WH/kg) relative to today’s battery technology while achieving 1,000 electric vehicles cycles. This will result in a significantly smaller, lighter weight, less expensive battery pack (below $100/kWh) and more affordable EVs,” the White House explained.

Lithium anodes can produce a higher density, but the challenge is longevity. As of 2021, the consortium had demonstrated 600 cycles, an important milestone but far short of the goal.

Along with PNNL, the original consortium included the Brookhaven and Idaho national laboratories, the SLAC National Accelerator Laboratory, and universities in New York, California, and Texas along with IBM and Tesla (named Tesla Motors at the time).

The Search For A Better EV Battery Continues

So much for Phase I. Last December, the Battery500 consortium was re-upped for another five-year term at $15 million per year. The Energy Department labs and academic partners from Phase I are continuing into Phase 2, but IBM and Tesla have been replaced by General Motors (more on that in a second). Also joining in are additional universities in Texas, Pennsylvania, and Maryland.

“Phase 2 will allow us to build on the success of the last five years and provide the leadership necessary for developing the next generation of batteries, which will lead to a North American battery manufacturing and electric vehicle industry,” said M. Stanley Whittingham, who is a distinguished professor of chemistry at Binghamton University in New York State. Professor Whittingham received a Nobel Prize in 2019 for his work on lithium-ion batteries.

For the record, Whittingham’s co-recipient was another leader in the energy storage field, Professor John Goodenough of the University of Texas – Austin, which is also a member of the consortium.

The Latest EV Battery Breakthrough

In Phase II, the Battery500 Consortium continues to aim at building up lithium-metal EV batteries to a specific energy goal of up to 500 Wh/kg while reducing the cost below $100 per kilowatt-hour.

The latest development concerns new research led by the Brookhaven lab, where a team has been studying the interphase. The interphase is a “squishy” layer that grows between the anode and the electrolyte with every charging cycle. It is considered to be the “key to stabilizing lithium metal batteries.”

“The interphase influences the cyclability of the whole battery. It’s a very important, but elusive system,” said Brookhaven chemist Enyuan Hu, who led the research team. “Many techniques can damage this small, sensitive sample, which also has both crystalline and amorphous phases.”

Previous studies deployed cryo-electron microscopy and other sophisticated tools to pick apart the mysteries of the interphase, but knowledge gaps still remained. To fill them, the Brookhaven team has been bombarding the sample with ultrabright x-rays from the lab’s National Synchrotron Light Source II. Though intense, the rays enable researchers to get an up-close look at both phases of the sample without damaging it.

Three Big Breakthroughs For Better EV Batteries

The result was not one but three breakthroughs.

The new research identified lithium hydroxide from the anode as the likely contributor to lithium hydride in the interphase. The team anticipates that the discovery will lead to performance improvements in the interphase.

The team also found that a large amount of lithium fluoride can form in the low-concentration electrolytes. That upends previous research indicating that a high concentration is needed. If the new research is borne out, the next generation of batteries could reduce the amount of expensive salts needed to achieve a high concentration.

The third breakthrough involved a better understanding of the mechanisms at work when lithium hydroxide is consumed during charge-discharge cycles.

The US Army Wants Better EV Batteries

There is still a long way to go, but the US Army is now pitching in to help speed things along. Its involvement in the Battery500 Consortium project could have something to do with the appearance of GM. Last September the Consortium put out a call for solid-state “seedling” projects with support from the US Army Ground Vehicle System Center (GVSC).

The solicitation seeks progress in six areas, including the thickness of the solid-state electrolyte (“needs to be thin,” they say) and efficiency at room temperature. Blocking dendrite growth is another priority.

As for the Army’s interest in electric vehicles, the going has been rather slow in past years, but activity has been picking up in recent months. The military contractor Oshkosh is among those promoting the switch to electric drive, and earlier this year the GM Defense branch of GM’s announced that it is providing one of its all-electric GMC Hummers to the Army for demonstration and analysis.

“GM Defense will leverage the GMC HUMMER EV, featuring GM’s Ultium Platform, to meet the U.S. Army’s requirement for a light to heavy duty battery electric vehicle to support reduced reliance on fossil fuels both in the operational and garrison environments,” GM Defense explained, noting that vehicle features “1,000 horsepower, 11,500 lb-ft of wheel torque and is capable of full 350 kilowatt/800-volt DC fast charging, enabling up to nearly 100 miles in 12 minutes.”

The Army is also supporting solid-state energy storage research leading to better portable batteries for soldiers, so stay tuned for more on that.

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The Brookhaven energy storage research team: “Enyuan Hu and Sha Tan are chemistry researchers that used the XPD beamline for their work on batteries. Sanjit Ghose is the lead beamline scientist and a collaborator on this work,” courtesy of Brookhaven National Laboratory.