Battery Materials for Lithium-sulfur and Solid-state Batteries

Active and passive materials play a decisive role in the performance of battery cells and serve key functions in the development of new cell technologies. A holistic evaluation of the materials includes their chemical and structural characterization, as well as their processing into electrodes and cells, followed by electrochemical testing. In this way, electrochemical properties can be correlated with structural properties. We set our own standards through the development of new electrode materials for lithium-sulfur and solid-state batteries.
 

Materials Research for the Lithium-sulfur Batteries

Since 2010, the development of Li-S batteries has been a research focus at Fraunhofer IWS. Porous carbon materials, proprietary electrolyte systems, and new anode concepts are used in button and pouch cells and investigated under application-relevant conditions. This approach builds a comprehensive fundamental understanding, while innovations are protected within a patent portfolio. It forms the basis for the development of ultra-light prototype cells for new application areas.

• Kirchhoff, S. et al.: A Small Electrolyte Drop Enables a Disruptive Semisolid High-energy Sulfur Battery Cell Design via an Argyrodite-based Sulfur Cathode in Combination with a Metallic Lithium Anode
  Advanced Energy Materials, August (2024), DOI: 10.1002/aenm.202402204 
  
• Fiedler, M. et al.: The Role of Nanoporous Carbon Materials for Thiophosphate-based All Solid State Lithium Sulfur Battery Performance
  Carbon, June (2024), DOI: 10.1016/j.carbon.2024.119252
  
• Fiedler, M. et al.: Mechanistic Insights into the Cycling Behavior of Sulfur Dry-film Cathodes
  Advanced Sustainable Systems, February (2023), DOI: 10.1002/adsu.202200439 
   

Materials Innovations for Sulfidic Solid-state Batteries

Sulfide solid electrolytes are characterized by high ionic conductivity and good processability. They form the basis for a new generation of high-performance battery cells. At the same time, adaptation to the electrode materials and new concepts – particularly for the anode – are required. This is where Fraunhofer IWS contributes its own innovations, having, for example, demonstrated for the first time the solvent-free processing of cathode composites and the use of 100% silicon anodes in full cells.

• Mörseburg, S. et al.: A Metallic Lithium Anode for Solid-state Batteries with Low Volume Change by Utilizing a Modified Porous Carbon Host
  Carbon, January (2025), DOI: 10.1016/j.carbon.2024.119821  
• Rosner, M. et al.: Toward Higher Energy Density All‐solid‐state Batteries by Production of Freestanding Thin Solid Sulfidic Electrolyte Membranes in a Roll‐to‐roll Process
  Advanced Enery Materials, January (2025), DoI: 10.1002/aenm.202404790 
• Cangaz, S. et al.: Enabling High-energy Solid-state Batteries with Stable Anode Interphase by the Use of Columnar Silicon Anodes
  Advanced Energy Materials, July (2020), DOI: 10.1002/aenm.202001320 
   

Scalable Production of Ultra-thin Lithium Anodes

Lithium layers just a few micrometers thick are a key component for many solid-state battery cells. Developing scalable methods to produce these metallic anodes is a challenge that Fraunhofer IWS addresses with its own approach. A patented melt-coating process enables the deposition of thin lithium layers onto copper and nickel foils. Surface modification or their use for pre-lithiation of anode materials are subjects of ongoing research.

• Schönherr K. et al.: Liquid Lithium Metal Processing into Ultrathin Metal Anodes for Solid State Batteries
  Chemical Engineering Journal Advances, March (2022), DOI: 10.1016/j.ceja.2021.100218 
• Schönerr, K. et al.: Tailored Pre-lithiation Using Melt-deposited Lithium Thin Films
  Batteries, 2023, DOI: 10.3390/batteries9010053