Symmetric lithium sulfide – Sulfur cells: A method to study degradation mechanisms of cathode, separator and electrolyte concepts for lithium-sulfur batteries

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Markus Piwko - , Chair of Inorganic Chemistry I, Fraunhofer Institute for Material and Beam Technology (Author)
  • Christine Weller - , Chair of Inorganic Chemistry I, 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)
  • Holger Althues - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Stefan Kaskel - , Chair of Inorganic Chemistry I, Fraunhofer Institute for Material and Beam Technology (Author)

Abstract

Novel cathode, electrolyte and separator concepts are expected to improve the capacity retention and cycle life of lithium-sulfur batteries by avoiding the dissolution of polysulfide-intermediates into the electrolyte or preventing their diffusion to and reaction with the lithium metal anode. However, their intrinsic evaluation is obscured by ill-defined degradation mechanisms of the lithium counter electrode due to electrolyte and polysulfide consumption during reformation of the solid electrolyte interface. Herein, we introduce symmetric lithium sulfide – sulfur cells to study the “cathode" specific degradation mechanisms of the cathode/electrolyte/separator-system in order to differentiate cathode-, separator, and electrolyte and lithium metal anode degradation. Two identical carbon/sulfur-composite cathodes, either of them one at first lithiated versus lithium, are assembled in a coin cell versus each other. The virtue of this test cell design is demonstrated evaluating prime shuttle-suppression concepts, namely a Nafion-coated polyolefin separator and a sparingly polysulfide-solvating electrolyte. We conclude that symmetric lithium sulfide – sulfur cells provide a valuable methodology to analyze the intrinsic capacity decay and cycle life of cathodes for lithium-sulfur cells with limited solvation and/or blocking of polysulfides, and it is an essential strategy to distinguish cathode from lithium anode degradation.

Details

Original languageEnglish
Article numberA1084
JournalJournal of the Electrochemical Society
Volume165
Issue number5
Publication statusPublished - 2018
Peer-reviewedYes