Exploring the Solvation Sphere and Spatial Accumulation of Dissolved Transition-Metal Ions in Batteries: A Case Study of Vanadyl Ions Released from V2O5Cathodes

ACS Applied Energy Materials, vol. 5, pp. 449–460

Abstract

High Resolution Image Download MS PowerPoint Slide Dissolution of transition-metal ions from Li-ion battery cathodes is a well-known degradation phenomenon. In addition to capacity decrease due to metal loss in the bulk cathode, dissolved transition-metal ions might migrate through the electrolyte and participate in redox reactions resulting in electrolyte decomposition. Aside from the oxidation state and concentration of the transition metal, its ligand sphere and spatial accumulation have to be determined for complete characterization and prediction of possible detrimental impact. Here, pulse electron paramagnetic resonance and density functional theory are exploited to investigate the coordination and location of vanadyl ions, which are a dissolution product of V 2 O 5 cathodes. The solvation sphere is found to be dominated by electrolyte degradation products and also contains contributions from nonelectrolytic sources. Additionally, adjacent lithium and hexafluorophosphate ions are observed.

Authors 3

1. Conrad Szczuka corresponding Aachen Institute of Physical Chemistry

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

   Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany

2. Rüdiger‐A. Eichel Aachen Institute of Physical Chemistry

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

   Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany

3. Josef Granwehr Aachen Institute of Technical and Macromolecular Chemistry

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

   Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52056 Aachen, Germany