Analysis of the Electrochemical Stability of Sulfide Solid Electrolyte Dry Films for Improved Dry-Processed Solid-State Batteries

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Maria Rosner - , Chair of Inorganic Chemistry I, Fraunhofer Institute for Material and Beam Technology (Author)
  • Sahin Cangaz - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Felix Hippauf - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Susanne Dörfler - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Burak Aktekin - , Justus Liebig University Giessen (Author)
  • Thomas Meyer - , Justus Liebig University Giessen (Author)
  • Anja Henss - , Justus Liebig University Giessen (Author)
  • Thomas Abendroth - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Holger Althues - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Jürgen Janek - , Justus Liebig University Giessen (Author)
  • Stefan Kaskel - , Chair of Inorganic Chemistry I, Fraunhofer Institute for Material and Beam Technology (Author)

Abstract

The solvent-free processing of cell components is attracting growing interest, as it avoids energy-intensive drying and solvent recovery procedures. In solid-state batteries, the dry processing of solid electrolyte (SE) films results in improved ionic conductivities compared to wet processing and eliminates degradation due to residual solvent traces. For dry processing, the binder polytetrafluoroethylene (PTFE) is widely used due to its excellent fibrillation, but it shows poor electrochemical stability at low anode potentials. Here, the influence of processing parameters on the binder structure is evaluated, and the electrochemical degradation of the dry film separators is systematically investigated (e.g., CTTA measurements) at different anode potentials (Si and Li anode). A combination of electrochemical and surface characterization at the SE dry film/anode interface is conducted. The results confirm that processing has a large influence on the stability at the dry film/anode interface. By adapting the SE dry film processing, long-term cycling in Si||NMC pouch cells is demonstrated over more than 1300 cycles. Additionally, a high initial coulombic efficiency of 92% and an average CE of 99.7% are obtained over 100 cycles, highlighting the potential of dry film separators for the application with Si anodes.

Details

Original languageEnglish
Article numbere18517
JournalAdvanced functional materials
Publication statusE-pub ahead of print - 8 Oct 2025
Peer-reviewedYes

Keywords

Keywords

  • all-solid-state batteries, columnar silicon anodes, dry processing, LiPSCl, SE dry films, sulfide electrolytes