Efficient high-temperature sodium-sulfur batteries

Studies on the Efficiency, Aging, and Safety of Sustainable Sodium–Sulfur Batteries

Motivation: For a secure and climate-friendly electricity supply, electricity from wind and solar sources must be stored more effectively, as it is not always generated when it is needed. In the future, this will require large, stationary battery storage systems in particular. Sodium–sulfur batteries are especially well suited for this application because they are made from readily available and environmentally friendly raw materials. These materials can be sourced and processed in Europe, reducing long transport routes, environmental impacts, and dependencies on other countries. Despite these advantages, such batteries are not yet sufficiently economical. In current price-performance comparisons with lithium-ion batteries based on lithium iron phosphate (LFP), they lag slightly behind. To become price-competitive, the combination of storage capacity and longevity still needs to improve.

Objectives and Approach: The ENAS joint project addresses precisely these challenges. The goal is to make sodium–sulfur batteries more efficient and longer-lasting without compromising safety. To achieve this, several research partners with different areas of expertise work closely together. First, specialized test cells for laboratory use are being developed, as such research platforms do not yet exist in Germany. Subsequently, the negative electrode of the battery will be specifically enhanced to improve energy efficiency. In addition, the batteries will be subjected to accelerated aging in order to better study aging processes and identify potential safety risks at an early stage. Step by step, researchers will analyze how the battery behaves during operation in order to develop targeted optimization strategies.

Innovations and Perspectives: The project closes an important research gap in Germany and Europe and lays the foundation for broader use of this storage technology. The insights gained are intended to enable sodium–sulfur batteries to be used more economically in the future while maintaining reliability. This supports the expansion of renewable energy and simultaneously strengthens Germany as a research and industrial hub by creating new value chains and benefiting existing companies. In the long term, the project contributes to promoting a sustainable, secure, and independent energy supply in Germany and Europe and effectively supports the goals of the funding initiative.