Long-duration energy storage can't wait

The public wish list for battery makers is pretty straightforward. People want batteries that work for days without needing to be recharged, don't leak or catch fire, and provide reliable energy storage for many years.

Our currently available energy storage technology meets those needs for several categories of batteries. But as a nation, the United States has an urgent unmet need for safe and reliable long-duration energy storage on a massive scale. Fulfilling that need will require new kinds of batteries capable of routinely providing energy to our electric grid and hauling heavy freight long distances.

The Energy Storage Research Alliance (ESRA), a new Department of Energy (DOE) Energy Innovation hub, will meet those needs by accelerating the discovery of new battery materials and chemistries that use Earth-abundant components and green manufacturing processes.

The ESRA hub, one of two new energy storage-focused hubs created by DOE, includes leadership from three national laboratories: Pacific Northwest National Laboratory (PNNL), Lawrence Berkeley National Laboratory (Berkeley Lab), and Argonne National Laboratory, which serves as the hub's headquarters. In addition, 12 universities will participate in ESRA research.

"The ESRA will provide a platform for us to deepen our fundamental research in cost-efficient battery materials and affordable technologies," said PNNL's Wei Wang, ESRA deputy director and director of PNNL's Energy Storage Materials Initiative.

Now is the time

The ESRA hub has put into place the scientists, tools, and emerging technologies to rapidly identify the most promising science-based approaches to large-scale energy storage.

"In the last decade, our scientific understanding of how to store and release energy in chemical bonds has advanced dramatically," said Wang. "Now is the time to accelerate that fundamental understanding of the materials, chemistries, and properties that show promise in long-duration energy storage. Working with our partners, PNNL will leverage its investments in redox flow battery technology, high-throughput robotics, nuclear magnetic resonance spectroscopy, and the scientific acumen of our people."

Long-duration grid energy storage expertise

As our electric grid decarbonizes and comes to depend more and more on these intermittent energy sources, safe, dependable long-term energy storage becomes essential. PNNL battery experts have established scientific and technical prowess, and many patented advances, in one of the most promising ways to store intermittent energy: redox flow battery science.

Wang, a global leader in flow battery technology, and his PNNL colleagues are developing an accelerated approach to the discovery of even more efficient and longer-lasting flow battery materials for grid applications. In 2023, his research team provided the first lab-scale demonstration of a flow battery working stably and reliably for more than a year.

Through ESRA, Wang and his colleagues plan to explore a vastly increased number of new battery materials and chemistries, coupled with artificial intelligence, to learn faster and eliminate dead ends and blind alleys in their search.

"The ESRA hub builds upon PNNL's past projects and capabilities for fundamental science in energy storage, which have grown and matured with DOE Office of Science support," said Karl Mueller, director of program development for Physical and Computational Sciences at PNNL.

A molecular digital twin

To speed their effort, the scientists will deploy two tireless colleagues that are always available for more experiments. Dubbed Albert and Beverly, these two custom-built units are part robot, part workstation, part intelligent database. These lab dynamos have already sped the PNNL team's pace of new battery materials discovery.

Now, PNNL scientists will take them to a new level, collaborating with Argonne's artificial intelligence technologies. PNNL will also partner with scientists at Berkeley Lab who have a similar experimental system to look at solid-state batteries. The efforts will complement each other in the new ESRA hub, said Wang.

Together, the team will be able to further accelerate material discovery and move to predictive material design through machine learning insights.

"We can use machine learning to correlate structures to their properties," said Wang. "If the machine learning algorithm learns enough from those data, then the next time we modify a new structure or come up with a new structure, the algorithm would be able to predict with high fidelity whether that new structure would have properties of interest."

In this way, the scientific team can quickly move on from unpromising materials and focus on more productive ideas and prototypes. This combination of the robotic workstation and the machine learning algorithms make a sort of science-based molecular digital twin. The concept of a digital twin is well known in manufacturing, where digital prototypes guide real-world industrial design and manufacturing. Here, the team will extend that concept to their scientific discovery work.

"We know that chemical synthesis and experimental testing are the most time- and labor-intensive steps," said Wang. "The molecular digital twin will help us be more efficient with time and resources."

In addition to the digital twin, PNNL has signature characterization tools that will be housed in PNNL's Grid Storage Launchpad, a new facility dedicated to energy storage research that opened in August 2024.

Advanced nuclear magnetic resonance spectroscopy

Once a promising energy storage prototype is made, the research team will evaluate its ability to efficiently store energy, maintain its ability to charge and discharge, and be long-lasting. Researchers at PNNL have developed a unique facility, housed in PNNL's Energy Sciences Center, to "watch" experimental energy storage systems in action.

Dynamic nuclear polarization solid-state nuclear magnetic resonance allows scientists to obtain signals from a wider range of materials in a dynamic environment close to surfaces that are important for the movement of mass or charge in a battery.

This capability, along with specialized sample chambers developed at PNNL, allows scientists to track the movement of ions—the energy carriers—as they move within a liquid. In addition, the scientists will watch liquids interacting with both positive and negative electrodes. These interfaces are where many battery systems run into problems. Understanding the dynamic there is a huge endeavor.

"One of the biggest challenges in understanding complex chemistries found in energy storage systems is being able to track movement of the energy carriers and how they interact with the other elements of the system," said Vijay Murugesan, a PNNL materials science expert and scientific thrust lead of the new ESRA hub.

"We have developed the scientific and technical capabilities to track these energy storage molecules in real time, using advanced nuclear magnetic resonance spectroscopy."

Wang added, "Achieving ESRA goals requires a team science approach, and we are committed to moving forward not only to achieve scientific goals, but also to train the next generation of energy storage research scientists and engineers with diverse backgrounds. Our partnerships with 12 research universities will help us accomplish that goal."

Provided by Pacific Northwest National Laboratory