Research finds breakthrough needed for sodium-ion batteries to compete

Thousands of battery engineers and their supporters have long sought to make batteries cheaper than the dominant lithium-ion technology, hoping to capture a slice of the growing $50 billion annual lithium-ion market. . Sodium-ion batteries, the top contender among researchers, startups and venture capitalists, have received significant attention after lithium prices soared due to mineral supply chain challenges caused by COVID-19. There is.

Still, a new study in the journal Nature Energy says it could take years for sodium-ion batteries to reach low-cost candidates, requiring a series of technological advances and favorable market conditions.

Sodium-ion batteries are considered to have lower costs and more supply chain resilience than lithium-ion batteries. Despite many possibilities, sodium-ion batteries still face challenges. The amount of energy they can hold per pound tends to be lower than lithium-ion batteries.

Therefore, apart from the potential reduction in material prices, the cost per unit of stored energy remains higher for sodium-ion batteries. This could limit widespread commercial use unless breakthrough research is first achieved. The research focuses on areas with the greatest potential for progress, starting with a new collaboration between the Precourt Energy Institute at the Stanford Doerr School of Sustainability and the SLAC-Stanford Battery Center. This is due to a strong partnership.

The new program STEER assesses the technical and economic potential of emerging energy technologies and advises on “what to build, where to innovate and how to invest” for the energy transition. A new study evaluated more than 6,000 scenarios to test the robustness of the sodium-ion battery competitiveness roadmap.

“Lithium-ion battery prices will rise for the first time in 2022, warning that alternative batteries may be needed. Sodium-ion is perhaps the most attractive short-term challenger to lithium-ion, and many of battery companies are planning their next “It promises to significantly enhance sodium ion production and lower prices than existing ones,” said lead author of the study and founder and team leader of STEER, which launched in October. said Adrian Yao. It is scheduled for 2023 with support from three offices within the U.S. Department of Energy.

“It remains largely speculative as to whether, when, and how sodium-ion batteries might undercut lithium-ion in price, especially given that lithium-ion prices continue to fall. We recognized that it was something that could be done,” said Yao, a doctoral candidate who has returned to his doctoral program. For eight years, he was the founder and chief technology officer of a lithium-ion battery startup that now produces batteries on a large commercial scale.

Yao’s PhD co-advisor is the senior author of the new study and co-director of STEER. Sally Benson, Precourt Family Professor in the Department of Energy Science and Engineering, Doerr School of Sustainability; William Chueh is an associate professor of materials science in the School of Engineering, photon science at SLAC, and energy science and engineering in the Doerr School.

“This sodium ion research is the perfect business to launch STEER as a new way to guide research and investment toward the technology roadmaps most worth pursuing, and perhaps more importantly, the potential for success.” and move away from technology roadmaps that have low levels of performance,” Benson said.

Do’s and don’ts regarding sodium ions

The study highlights several important routes for sodium-ion battery developers to compete on price, particularly with lower-cost versions of lithium-ion batteries known as lithium iron phosphate. Most importantly, it increases energy density without using important minerals. Specifically, developers should target the energy density of lithium iron phosphate while moving away from nickel. Currently, most major sodium ion designs rely on relatively expensive metals.

“However, our main objective was not to predict in a particular year when price parity would be, but rather to reveal the impact of different market scenarios on the viability of competing technologies. ” said Chueh.

“As engineers and investors, we cannot assume that economies of scale will always cause prices to plummet once a device reaches commercial production. Yes, there is a learning curve, but we will quantify this curve here and say that it is not enough on its own. “By itself,” said Chue, who is also director of the Precourt Energy Institute. “Advances in engineering are likely to help reduce the cost of sodium-ion batteries beyond simply scaling up production.”

Such advances and new battery chemistries are worth pursuing in general, the researchers said. As the global transition to sustainable energy requires more energy storage, continuing to rely heavily on lithium-ion batteries poses security, economic and geopolitical risks. .

For example, the study examines how the competitiveness of sodium ions would accelerate if a supply shock occurred in graphite, a key material used in lithium-ion batteries, of which China controls more than 90% of global supply. We are simulating what will happen. In fact, on December 3, 2024, China began significantly restricting graphite exports to the United States, while also banning exports of three other important minerals.

The study also identifies market forces and supply chain conditions that could inhibit competition between sodium and lithium ions. For example, if lithium prices remain close to current historical lows, the technology routes through which sodium ion can gain price advantage over the next decade will narrow.

“One of the key things we learned from industry experts is that while battery cell price is important, the technology is only successful at the system level, such as electric vehicles or grid-scale battery energy storage systems. So now we’re expanding our coverage to provide a more holistic view, including understanding the costs of safety and other system considerations,” Yao said.

to the next

STEER is beginning to apply its approach to other technology areas as well. The researchers are investigating the supply chain for graphite, an important and often overlooked mineral. Industry executives and Energy Department leaders advised appropriate questions to ask and answer at a roundtable in Washington, D.C., in September. The workshop brought together more than 40 industry organizations, connecting all graphite manufacturers as well as the value chain from mining companies to car manufacturers.

“Thanks to our collaborators in industry, government and other research institutions, STEER is able to identify the paths that are most likely to contribute to the energy transition and those that are most likely to lead nowhere.” Benson said. “Our team combines commercial deployment experience, technology roadmaps and systems thinking.”

The STEER team will also analyze technology roadmaps in long-term energy storage and other energy transition areas such as hydrogen and industrial decarbonization.