Lithium and sodium-ion technologies are more closely linked than assumed
Batteries are considered a key technology for the global energy and mobility transition. In addition to established lithium-ion batteries, sodium-ion batteries are becoming increasingly important, primarily due to their cost advantages and independence from scarce raw materials such as lithium or cobalt. Until now, policymakers and the media have often viewed such new battery types as an opportunity to quickly catch up with market leaders technologically. However, a study recently published in the journal Nature Energy by a research team from the University of Münster, ETH Zurich (Switzerland), Stanford University (USA), and the Fraunhofer Research Institution for Battery Cell Production (FFB) shows that such a technological restart is more difficult than expected, as the new technologies build heavily on existing knowledge.
Specifically, this means that established market players have structural advantages because they can utilise cross-chemical production and design expertise. As a result, the barriers to market entry for new players are higher than is often discussed. The researchers warn that common forecasts which model different battery technologies as independent learning paths could systematically distort cost developments and competitive dynamics. "Our results show that switching to a new battery technology does not automatically open the door to new market players", explains Dr 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 groundbreaking for industrial policy. "Policy strategies should view batteries as technologically uniform systems", emphasises Prof Tobias Schmidt from ETH Zurich. "A competitive advantage is not gained through isolated expertise, but through the mastery of overarching technological capabilities."
The scientists analysed more than 15,000 patents. Using artificial intelligence (Large Language Models), they automatically classified the patents according to electrode materials and type of innovation (product or process innovation) and reconstructed how the knowledge was passed on. The results show a massive, ongoing exchange of knowledge across different lithium-ion variants and between lithium-ion and sodium-ion batteries. 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.
In addition to the industrial policy implications, the study also sets new standards in terms of methodology: For the first time, the team combined AI-supported patent classification with an analysis of how patents build on one another over time. The approach can be transferred to other technological fields in order to recognise technological dependencies and barriers to market entry at an early stage.
Original publication
André Hemmelder, Anurag Panda, Leopold Peiseler, Simon Lux, Jens Leker, Tobias S. Schmidt (2026): Knowledge interdependencies between lithium- and sodium-ion battery chemistries. Nature Energy 11, 313–323; DOI: 10.1038/s41560-026-01985-z