Are sodium-ion batteries really the chance for a fresh start?

Until now, new battery types such as sodium-ion batteries have often been seen in politics and media as an opportunity to quickly catch up on technological backlogs compared to market leaders. A research team from several battery institutes has examined this in a study and expresses doubts about this opportunity.

Fraunhofer ifam natrium ionen batterie entwicklung — Image: Fraunhofer IFAM

A recent study published in the journal Nature Energy by a research team from the University of Münster, ETH Zurich, Stanford University, and the Fraunhofer Research Institution for Battery Cell Production (FFB) reveals that achieving a technological fresh start is more challenging than anticipated. The study demonstrates that new battery technologies rely heavily on existing knowledge. “Our results show that switching to a new battery technology does not automatically open the door to new market players,” Dr André Hemmelder from the University of Münster stated about the findings.

For the study, scientists from the participating institutes analysed more than 15,000 patents using artificial intelligence. Large language models were employed to automatically classify the patents by electrode materials and type of innovation (product or process innovation). Based on this classification, the team reconstructed how knowledge was transferred over time. In essence, the study examined how patents built upon one another over the years. The researchers see potential in this approach—combining AI-supported patent classification with temporal analysis—to apply it to other technology fields, enabling the early identification of technological dependencies and market entry barriers.

Study reveals “massive, ongoing exchange of knowledge”

According to the press release, the evaluation of the battery sector uncovered “a massive, ongoing exchange of knowledge across different lithium-ion variants and between lithium-ion and sodium-ion batteries.” The University of Münster explained that in particular, “there is a transfer of knowledge from established lithium-ion technology to newer sodium-ion technologies.” “In some cases, such as between different lithium-ion technologies, this cross-technology knowledge exchange is even stronger than further development within the same technology,” the study found.

This means that established market players hold structural advantages, as they can leverage cross-chemistry production and design knowledge. Consequently, the researchers argue that market entry barriers for new players are “higher than often discussed.” They explicitly warn that common forecasts, which model different battery technologies as independent learning pathways, may systematically distort cost developments and competitive dynamics.

The study’s findings align with recent developments in China. Battery giant CATL is pushing its Naxtra brand for sodium-ion batteries into the market, while automakers like Changan plan to validate solid-state cells in vehicles later this year, alongside the continued development of conventional lithium-ion batteries with liquid electrolytes. Meanwhile, European cell factories are still ramping up lithium-ion cell production, and sodium-ion or solid-state batteries remain research projects or are being advanced by startups, but have yet to be commercialised.

“Our results show that switching to a new battery technology does not automatically open the door to new market players,” explained André Hemmelder from the University of Münster. “Established companies continue to extend their lead by simply transferring their existing knowledge of design and production. For new entrants without experience in the field of lithium-ion batteries, this creates significantly higher hurdles than previously assumed.”

These findings are also pivotal for industrial policy. “Policy strategies should view batteries as technologically uniform systems,” emphasised Tobias Schmidt from ETH Zurich. “A competitive advantage is not gained through isolated expertise, but through the mastery of overarching technological capabilities.”