Correlation of the electronic structure and Li‐ion mobility with modulus and hardness in LiNi0.6Co0.2Mn0.2O2 cathodes by combined near edge X‐ray absorption finestructure spectroscopy, atomic force microscopy, and nanoindentation

Electrochemical Science Advances, vol. 4

Abstract

Abstract The electrochemical performance of cathode materials in Li‐ion batteries is reflected in macroscopic observables such as the capacity, the voltage, and the state of charge (SOC). However, the physical origin of performance parameters are atomistic processes that scale up to a macroscopic picture. Thus, revealing the function and failure of electrochemical devices requires a multiscale (and ‐time) approach using spectroscopic and microscopic techniques. In this work, we combine near‐edge X‐ray absorption fine structure spectroscopy (NEXAFS) to determine the chemical binding state of transition metals in LiNi0.6Co0.2Mn0.2O2 (NCM622), electrochemical strain microscopy to understand the Li‐ion mobility in such materials, and nanoindentation to relate the mechanical properties exhibited by the material to the chemical state and ion mobility. Strikingly, a clear correlation between the chemical binding, the mechanical properties, and the Li‐ion mobility is found. Thereby, the significant relation of chemo‐mechanical properties of NCM622 on a local and global scale is clearly demonstrated.

Authors 4

1. Florian Hausen corresponding Aachen Institute of Physical Chemistry

   RWTH Aachen University · Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Institute of Energy and Climate Research IEK‐9, Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Physical Chemistry, RWTH Aachen University Aachen Germany

   Jülich Aachen Research Alliance, JARA‐Energy Jülich Germany

   Institute of Energy and Climate Research IEK‐9, Forschungszentrum Jülich GmbH Jülich Germany

2. Niklas Scheer Aachen Institute of Physical Chemistry

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research IEK‐9, Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Physical Chemistry, RWTH Aachen University Aachen Germany

   Institute of Energy and Climate Research IEK‐9, Forschungszentrum Jülich GmbH Jülich Germany

3. Bixian Ying

   University of Münster

   Affiliation as printed

   Münster Electrochemical Energy Technology (MEET) University of Münster (WWU) Corrensstraße 46 Münster Germany

4. Karin Kleiner corresponding

   University of Münster

   Affiliation as printed

   Münster Electrochemical Energy Technology (MEET) University of Münster (WWU) Corrensstraße 46 Münster Germany