Establishing Li-acetylide (Li2C2) as functional element in solid-electrolyte interphases in lithium-ion batteries

Journal of Power Sources Advances, vol. 28, pp. 100152

Abstract

Previously, lithium-acetylide (Li 2 C 2 ) had been identified as electrolyte degradation product on lithium-metal based electrodes using Raman spectroscopy . This raised the question, if Li 2 C 2 is also be formed on graphitic electrodes in lithium-ion batteries without lithium metal present. In order to shed light on this research question, we performed a series of in situ Raman experiments with graphitic electrodes in half- and full-cell configuration. The recorded cell potential dependent spectra clearly prove the presence of Li 2 C 2 in the lithiated state of the electrodes, but the according peak vanishes when delithiating. This observation indicates a somewhat reversible process involving Li 2 C 2 . Several chemical/electrochemical reactions are in question to contribute to this effect. With respect to its properties and potential role in the solid-electrolyte interphase (SEI) DFT calculations of Li 2 C 2 -nanoclusters were performed, which revealed an exceptionally low energy band gap, hence a remarkable electric conductivity . In conjunction with a relatively high ionic conductivity , Li 2 C 2 appears to play a key role in the degradation of lithium-ion batteries, which had not yet been revealed nor taken into account in simulations of the interphase.

Authors 5

1. Viviane Maccio‐Figgemeier Aachen Aging Processes and Lifetime Prediction of Batteries Institute for Power Electronics and Electrical Drives (ISEA)

   Forschungszentrum Jülich · Helmholtz-Institute Münster · RWTH Aachen University

   Affiliation as printed

   Aging Processes and Lifetime Prediction of Batteries, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, Jägerstrasse 17-19,52066 Aachen, Germany

   Helmholtz-Institute Münster (HI MS): Ionics in Energy Storage (IEK-12), Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149 Münster, Germany

2. Gebrekidan Gebresilassie Eshetu

   Forschungszentrum Jülich · Helmholtz-Institute Münster

   Affiliation as printed

   Helmholtz-Institute Münster (HI MS): Ionics in Energy Storage (IEK-12), Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149 Münster, Germany

3. Damian Mroz

   Forschungszentrum Jülich · Helmholtz-Institute Münster

   Affiliation as printed

   Helmholtz-Institute Münster (HI MS): Ionics in Energy Storage (IEK-12), Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149 Münster, Germany

4. Hyunsang Joo Aachen Aging Processes and Lifetime Prediction of Batteries Institute for Power Electronics and Electrical Drives (ISEA)

   RWTH Aachen University

   Affiliation as printed

   Aging Processes and Lifetime Prediction of Batteries, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, Jägerstrasse 17-19,52066 Aachen, Germany

5. Egbert Figgemeier corresponding Aachen Aging Processes and Lifetime Prediction of Batteries Institute for Power Electronics and Electrical Drives (ISEA)

   Forschungszentrum Jülich · Helmholtz-Institute Münster · RWTH Aachen University

   Affiliation as printed

   Aging Processes and Lifetime Prediction of Batteries, Institute for Power Electronics and Electrical Drives (ISEA), RWTH Aachen University, Jägerstrasse 17-19,52066 Aachen, Germany

   Helmholtz-Institute Münster (HI MS): Ionics in Energy Storage (IEK-12), Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149 Münster, Germany