Identification of Soluble Degradation Products in Lithium–Sulfur and Lithium-Metal Sulfide Batteries
Fabian Horsthemke,
Christoph Peschel,
Kristina Kösters,
Sascha Nowak,
Kentaro Kuratani,
Tomonari Takeuchi,
Hitoshi Mikuriya,
Florian Schmidt,
Hikari Sakaebe,
Stefan Kaskel,
Tetsuya Osaka,
Martin Winter,
Hiroki Nara,
Simon Wiemers-Meyer
Affiliations
Fabian Horsthemke
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Christoph Peschel
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Kristina Kösters
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Sascha Nowak
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Kentaro Kuratani
Research Institute of Electrochemical Energy, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
Tomonari Takeuchi
Research Institute of Electrochemical Energy, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
Hitoshi Mikuriya
Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan
Florian Schmidt
Department of Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
Hikari Sakaebe
Research Institute of Electrochemical Energy, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
Stefan Kaskel
Department of Chemistry, Technische Universität Dresden, 01062 Dresden, Germany
Tetsuya Osaka
Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan
Martin Winter
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Hiroki Nara
Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan
Simon Wiemers-Meyer
MEET Battery Research Center, University of Münster, Corrensstraße 46, 48149 Münster, Germany
Most commercially available lithium ion battery systems and some of their possible successors, such as lithium (metal)-sulfur batteries, rely on liquid organic electrolytes. Since the electrolyte is in contact with both the negative and the positive electrode, its electrochemical stability window is of high interest. Monitoring the electrolyte decomposition occurring at these electrodes is key to understand the influence of chemical and electrochemical reactions on cell performance and to evaluate aging mechanisms. In the context of lithium-sulfur batteries, information about the analysis of soluble species in the electrolytes—besides the well-known lithium polysulfides—is scarcely available. Here, the irreversible decomposition reactions of typically ether-based electrolytes will be addressed. Gas chromatography in combination with mass spectrometric detection is able to deliver information about volatile organic compounds. Furthermore, it is already used to investigate similar samples, such as electrolytes from other battery types, including lithium ion batteries. The method transfer from these reports and from model experiments with non-target analyses are promising tools to generate knowledge about the system and to build up suitable strategies for lithium-sulfur cell analyses. In the presented work, the aim is to identify aging products emerging in electrolytes regained from cells with sulfur-based cathodes. Higher-molecular polymerization products of ether-based electrolytes used in lithium-sulfur batteries are identified. Furthermore, the reactivity of the lithium polysulfides with carbonate-based solvents is investigated in a worst-case scenario and carbonate sulfur cross-compounds identified for target analyses. None of the target molecules are found in carbonate-based electrolytes regained from operative lithium-titanium sulfide cells, thus hinting at a new aging mechanism in these systems.
