Powering up to solve challenges in energy storage

Rewind to 2006. Electric vehicles (EVs) were emerging, but—despite mounting pressure to decarbonize the energy sector—the research community had not broadly recognized the importance of energy storage. At Pacific Northwest National Laboratory (PNNL), battery research was practically non-existent.

Today, PNNL is lauded for its battery research, leading several major energy storage programs for the Department of Energy (DOE). So: how did PNNL go from a new player to a leader in state-of-the-art storage for EVs and the grid?

Plugging in

In the mid-2000s, PNNL posed a daunting question: what was the most important problem its researchers could solve with their expertise in materials sciences?

A group led by Jun Liu—at the time, a PNNL materials scientist and laboratory fellow—coordinated a year of brainstorming. Through discussions with experts from laboratories, industry, and government, the group landed on an answer: energy storage. With renewable energy booming and fossil fuel frustration growing, the country needed reliable, powerful batteries—not just for transportation, but for the grid, as well.

The team scoped the initiative, conducting the first-ever quantitative analysis of domestic energy storage needs and mapping the intellectual property landscape to understand where the U.S. and PNNL could play leadership roles.

"PNNL had strengths in materials sciences, characterization tools, and simulations—but we needed a strategy to apply and expand those capabilities to address the scientific challenges in energy storage," said Liu, now a Battelle Fellow who holds a joint appointment with the University of Washington.

In 2007, PNNL launched the Transformational Materials Science Initiative, a five-year, $7 million internal investment led by Liu and Jud Virden, who now serves as Associate Laboratory Director for Energy and Environment.

"The initiative really kickstarted our efforts in grid energy storage," said Virden. "It allowed us to bring researchers from different disciplines together to focus on key scientific challenges."

Powering up

Early research under the initiative—on lithium and silicon anodes, sulfur-based batteries, high-voltage cathodes, functional electrolytes, and more—built fundamental knowledge to support next-generation battery technologies.

Projects ran the gamut from vehicle battery compositions (such as lithium-oxygen and lithium-sulfur) to grid-suited redox flow batteries that prioritized energy capacity (watt-hours) over energy density (watt-hours per cubic meter). PNNL developed capabilities to monitor battery degradation, including the unprecedented ability to use electron microscopes to watch battery capacity fade in real-time.

Other battery work poured in. PNNL conducted research on primary high-energy lithium-air batteries. PNNL won the first award issued under the ARPA-E program for a proposal to reduce the operating temperatures of sodium-based batteries—research that led to those batteries operating at 50% lower temperatures.

DOE's Vehicle Technologies Office (VTO) selected PNNL proposals for competitive battery programs, and the Office of Electricity (OE) chose PNNL for its first major investment in grid energy storage research. Through the latter project, PNNL developed electrolytes that improved batteries' energy densities and operating temperatures. Those electrolytes are now licensed to several companies.

In the early 2010s, PNNL's battery researchers teamed with other national laboratories and the Office of Science to coordinate energy storage research. In 2012, this effort was formalized when the DOE—seeing value in combining this expertise—launched the Joint Center for Energy Storage Research with PNNL as a partner.

Building capacity

As interest in EVs grew, battery range posed concerns. In 2016, the DOE selected a PNNL-led team to lead one of the largest EV battery research programs in the world: the Battery500 Consortium. The program, directed by Liu, aims to help create rechargeable lithium-metal EV batteries, delivering 500 watt-hours per kilogram—twice the current best-in-class—across 1,000 charge-discharge cycles.

The consortium's first phase produced a prototype 350 watt-hour/kilogram lithium-metal battery with a lifetime of 600 cycles—a record-setting step toward lighter, longer-lasting, and less expensive EVs. Now in its second phase, the consortium has started demonstrating 400–450 watt-hour/kilogram batteries with stable cycling, nearing its headline goal.

In 2019, two of the consortium's principal investigators—John Goodenough (a professor at The University of Texas at Austin) and Stan Whittingham—received the Nobel Prize in Chemistry for pioneering battery research.

"Battery500 has been a great collaborative effort, where we are making key breakthroughs without the hype that is all too common these days," said Whittingham, a distinguished professor of chemistry at Binghamton University. "However, I have found the most rewarding part—in addition to the scientific accomplishments—has been watching the junior scientists grow and take key leadership positions."

"The consortium's success isn't just in developing next-generation batteries," Liu added. "It's also in how we identified scientific problems, aligned resources to address challenges, improved how people worked together—even how we set community standards for how to conduct battery research."

Generating momentum

Now far-reaching, PNNL's energy storage programs have produced countless patent applications and high-impact papers. The Lab's breakthroughs—many licensable—address longevity, capacity, and cold-weather performance, and have improved technologies from lithium-ion and lithium-metal batteries to flow and sodium-ion batteries.

"PNNL's approach was to integrate fundamental research with practical applications and collaborate with others," Virden said. "The integration and coordination from scientific discovery to technology development enables PNNL to have an enormous impact in the energy storage community."

PNNL's energy storage laboratories are now packed with highly cited—and frequently lauded—researchers. Some scientists hired through the 2007 initiative are now senior researchers at PNNL, leading national battery programs and cultivating new talent. (To that end, PNNL also offers internships and fellowships in energy storage.)

Current affairs

Increasingly, PNNL works with partners like Albemarle Corporation and Applied Materials to de-risk materials manufacturing and deploy new storage technologies in the real world. "The PNNL thread is there from the high-quality scientific papers all the way to these industrial investments," Virden said.

Other ongoing industrial partnerships include work with GM and the University of Washington to cost-effectively produce single-crystal cathodes and work with ESS, Chemous, Otoro Energy, and the DOE's Advanced Materials & Manufacturing Technologies Office to apply AI to flow battery manufacturing.

PNNL also leads the new Cathode-Electrolyte Interphase Consortium, sponsored by VTO, which focuses on the layers between lithium-ion battery cathodes and electrolytes—a major determinant of battery performance. Jie Xiao, the first postdoc hired under PNNL's 2007 initiative, leads the consortium. Xiao is now a Battelle fellow, heading PNNL's 70+ member Battery Materials & Systems Group.

Last year, PNNL and five other national labs were selected by OE to form the Rapid Operational Validation Initiative, which is applying AI to validate the performance of new energy storage systems.

Soon, PNNL will open the Grid Storage Launchpad—a $75 million facility, with additional investments from the State of Washington, Battelle, and PNNL. Here, PNNL's researchers will test next-generation batteries as big as 100kW under realistic grid conditions. The building will also host PNNL's EV battery research.

"The Grid Storage Launchpad will add a national capability for rigorous testing and battery development," Virden said. "Energy storage remains a critical challenge for the country, and we are excited to continue working with our industry and university partners to accelerate our transition to a resilient and carbon-free energy infrastructure."

All said, a far cry from the state of the lab's energy storage research in 2007, and a paradigm shift in the landscape of grid energy storage.

"Launching a grid battery research program was a bold idea at the time," Virden recalled. "We pushed ourselves to work with the best researchers in the country to identify where we could deliver the greatest national impact—which is exactly what a national lab should do."

Provided by Pacific Northwest National Laboratory